Synthesis and NMR elucidation of novel amino acid cavitand derivatives

Accepted Manuscript Synthesis and NMR Elucidation of Novel Amino Acid Cavitand Derivatives Iman Elidrisi, Pralav V. Bhatt, Thavendran Govender, Hendrik G. Kruger, Glenn E.M. Maguire PII:

S0040-4020(14)00616-4

DOI:

10.1016/j.tet.2014.04.082

Reference:

TET 25532

To appear in:

Tetrahedron

Received Date: 19 February 2014 Revised Date:

8 April 2014

Accepted Date: 25 April 2014

Please cite this article as: Elidrisi I, Bhatt PV, Govender T, Kruger HG, Maguire GEM, Synthesis and NMR Elucidation of Novel Amino Acid Cavitand Derivatives, Tetrahedron (2014), doi: 10.1016/ j.tet.2014.04.082. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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ACCEPTED MANUSCRIPT Graphical Abstract Synthesis and NMR Elucidation of Novel Amino Acid Cavitand Derivatives *Corresponding author: [email protected]

Iman Elidrisi, Pralav V. Bhatt, Thavendran Govender, Hendrik G. Kruger and Glenn E. M.

R'

H6 O H5

H6 O

O

H H6 O 2

R' O

H6

H5

H4 H2

H4

O

R H R

O

H

H

O

H R R H2 O

O H 2 H4

O R'

H6

H4

O

H5

H6

O O

H5

H6

R' R = C11H 23

O

7a-i

7g R' = L-Ser (O t-but) t-butyl ester

7c R' = L-Phe methyl ester

7h R' = L-Glu (OMe) methyl ester

7e R' = L-Pro methyl ester

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7f R' = L-Trp methyl ester

7b R' = L-Ala methyl ester

7d R' = L-Leu methyl ester

O

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7a R' = Gly ethyl ester

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H6

SC

O

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Maguire.*

7i R'= L-Lys (Z) benzyl ester

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ACCEPTED MANUSCRIPT Synthesis and NMR Elucidation of Novel Amino Acid Cavitand Derivatives

ImanElidrisi,[a] Pralav V. Bhatt,[b] Thavendran Govender,[b] Hendrik G. Kruger,[a] and Glenn E. M. Maguire [a]* a

School of Chemistr and Physicsy, University of KwaZulu-Natal, Westville Campus, Private

BagX54001, Durban 4000 South Africa, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag

X54001, Durban 4000 South Africa

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*Email: [email protected]

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b

Abstract

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The synthesis of seven novel protected amino acid cavitands is reported. All have four pendant n-undecyl chains and “headgroups” connected by a two-carbon spacer at four positions on the aromatic rings.

The amino acids employed are glycine, alanine, phenylalanine, leucine,

proline, tryptophan, serine, glutamine and lysine.

The structures of the compounds were

elucidated using one-and two-dimensional NMR techniques which verified that all tetra-

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substituted cavitands have symmetrical C4v conformation. This is the first example of a complete study for amino acid cavitand derivatives.

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Keywords: amino acid cavitands; NMR; 1H-NMR; COSY; HSQC.

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ACCEPTED MANUSCRIPT Introduction

To a large extent, the progress of supramolecular chemistry relies on the diversity of building blocks available for the construction or synthesis of structures with functional properties.1 In this regard, cavitands are certainly one of the most important classes of host molecules possessing well-defined cavities. The original term was coined by Cram, who defined cavitands complementary organic compounds or ions’.2

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as ‘synthetic organic compounds with enforced cavities large enough to complex

One example of a family of these macrocycles employed by Cram are ‘resorcin[4]arenes’ whose phenolic OH groups can be further ‘bridged’ with appropriate bifunctional reagents

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(BrCH2Cl would be the simplest example) to yield the bowl-shaped cavitands.3 The binding properties of these macrocyclics have been intensively studied in the solid state,3 gas phase,4

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and in organic solvents.5,6 Cavitands have been equipped with various substituents at the upper and lower rims.7-9 These derivatives in recent years have been extensively studied as starting materials for the preparation of a wide variety of molecular receptors to recognize metal ions,1014

anions15-17 and organic guest molecules,18,19 forming host-guest or supramolecular

complexes.

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Surprisingly, although they have been widely studied,7-9 cavitands have only been used infrequently as topological templates in combination with amino acids or peptides. Sherman and co-workers have connected amino acids and peptides to a cavitand using a thiol bridge at the upper rim to create helical conformations.20,21

Berghaus and Feigel have connected

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peptides and amino acids to an aminomethylcavitand22 yielding shorter more compact structures. These examples gave clear evidence of intra- and intermolecular hydrogen-bonded

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organization in non-polar solvents.

The present study is an effort to functionalise the upper rim of a cavitand with a range of single amino acid residues while possessing undecyl “feet” at the lower rim. The amino acids chosen for this study have a broad range of side chains. They include non-polar sidechains such as glycine, alanine, phenylalanine, leucine, proline and tryptophan and polar sidechains such as serine, glutamic acid, and lysine.

The alanine and phenylalanine derivatives have been

reported previously but in that case full 2D elucidation was not carried out.23 This is the first example of a complete NMR spectroscopic study for this family of compounds.

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ACCEPTED MANUSCRIPT Results and discussion

Scheme 1, illustrates the proposed synthetic pathway towards the target compounds using the acid chloride of tetra-acid cavitand as an intermediate. The synthesis of the tetra-acid cavitand has been reported to provide adequate yields.24,25 The synthetic route involves alkylation of compound 4 with methyl-2-bromoacetate in dry acetonitrile in the presence of potassium

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carbonate at 82 ºC for two days. The procedure gave compound 5 in 98 % yield. Subsequent hydrolysis of 5 using potassium hydroxide solution in THF at room temperature for 24 hours, gave 6 in essentially quantitative yield.24,25 NBS, 2-butanone

OH

4 C11H23

Br HO

BrClCH2, K2CO3

OH

0°C

O

DMF, 65 °C

4 C11H23

1

Br

O

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HO

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OH

O

O O

2 M KOH THF, rt

O

O

Methyl-2-bromo acetate/ K2CO3

OH O

Dry CH3CN, reflux, 48 h C11H23 4 5 (98%)

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C11H23 4 6 (96%)

-78 °C

OCH3 O

O

4

3 (72%)

2 (87%)

i) Dry THF, n-BuLi, B(OCH3)3 ii) 15% H2O2: 1.5 M NaOH (1:1)

O

C11H23

O

C11H23

4

4 (53%)

i) Oxalyl chloride, dry CH2Cl2, rt

ii) Amino acid ester, Et3N, dry CH2Cl2, 0 °C

R'

7a R' = Gly ethyl ester

7f R' = L-Trp methyl ester

7b R' = L-Ala methyl ester

7g R' = L-Ser (O t-but) t-butyl ester

7c R' = L-Phe methyl ester

7h R' = L-Glu (OMe) methyl ester

7d R' = L-Leu methyl ester

7i R'= L-Lys (Z) benzyl ester

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O

O O

O

AC C

C11H23 4

7e R' = L-Pro methyl ester

7a- i (58-74%)

Scheme 1: The synthetic pathway towards the target compounds using the tetra-acid cavitand as a precursor.

With reference to Figure 1, the various signals present in the 1H NMR spectra of 5 and 6 were assigned. Alkylation of the four hydroxyl groups in 4 with methyl-2-bromoacetate afforded 5, resulting in the appearance of a singlet due to the isotropic nature of the methylene protons at 4.52 ppm (H6), integrating to eight. This signal appears at a higher frequency due to the electronegativity of the neighbouring oxygen atom and carbonyl group.

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ACCEPTED MANUSCRIPT R'

H5

H6 O

H6

O

O

H4 H2 O H 6

H4 O H2

O

H6

R H R H H

O

O

R H R

H6 O

H 2O H4

H4H2 H5

O O H6

R = C11H23

O H6

R'

O

5 R' = OCH3 6 R' = OH

H5

O H6

R'

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R'

H5

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O

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Figure 1: Expanded structure of 5 and 6, showing distinctive protons.

The signal related to the methoxy group of 5 appears as a singlet at 3.76 ppm, integrating to twelve. The signals related to H4 and H5 protons appear as two doublets, both integrating to four; one at 4.39 ppm (for the inner protons, H4) and the other at 5.70 ppm (for the outer protons, H5). The signal for the aromatic cavitand protons appears at 6.77 ppm as a singlet, integrating to four. The signal for the methine protons (H2) appears as a triplet at 4.67 ppm,

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integrating to four. The signals related to the undecyl “feet” are largely unchanged from 4, and maintain the associated multiplicity and integration. Hydrolysis of the tetra-ester cavitand 5 to 6was accomplished in THF under basic conditions

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and confirmed in the 1H NMR spectrum by the disappearance of the signal associated with the methoxy group in 5. The methylene protons (H6, Figure 1) signal of the OCH2CO is observed

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as a singlet at 4.44 ppm, integrating to eight. The signal related to the aromatic cavitand protons appears at 7.23 ppm as a singlet, integrating to four. The signal for H2 appears as a triplet at 4.54 ppm, integrating to four. The signals related to the undecyl “feet” have resolved into three signals: a quartet at 2.20 ppm (the first CH2 group of the undecyl feet attached to the cavitand), integrating to eight, a broad multiplet at 1.20-1.30 ppm, integrating to 72, and a triplet at 0.88 ppm, integrating to twelve. The tetra-acid cavitand 6 was transformed into activated tetra-acyl chloride upon treatment with oxalyl chloride in dry methylene chloride (Scheme 1). Since the acyl chloride is very unstable and undergoes rapid hydrolysis if moisture is present, it was used in the next step without further purification and characterization. This acyl chloride was reacted with five equivalents of the appropriate amino acid ester in the presence of triethylamine as the catalyst in dry methylene chloride at 0 ºC. The reaction mixture was then allowed to equilibrate to

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room temperature and stirred for 18 hours as for similar couplings in the literature.26-28 In this protocol, the amino acids that needed side chain protection (e.g., L-glutamic acid, L-serine, and L-lysine)

were used protected as seen in Figure 2. The resulting residue products were purified

by silica gel chromatography. The target compounds 7a-I are all novel and were obtained in reasonable yields (58-74 %). The amino acids that were chosen as hydrogen-bond forming moieties for this study were glycine 7a, L-alanine7b, L-phenylalanine 7c, L-leucine 7d, L-

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proline 7e, L-trypotophan7f, L-serine 7g, L-glutamic acid7h, and L-lysine 7i. The structures of these compounds were established based on one- and two-dimensional NMR experiments. With reference to Figure 2, the various signals present in the 1H NMR spectra of the tetra-

O

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substituted cavitand derivatives 7a-i were assigned. R'

H6 O

R' O

O

H5

H4 H2

H4 O H2

H6 H6

H6 O

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H5

O

R H R

O

H

H

O

H R R

R'

H4

O

O

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H5

O

H6

H2 O

O H 2 H4

H6

O

H5

H6

H6

R'

R = C11H23

β αO

O

OCH2 CH3

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α

O

7a-i

7a R' =

OCH3

7b R' =

NH

NH

β

AC C

7c R' =

7e R' =

7g R' =

α

O

δ OCH3

δ

δ

t-BuO

α

O

NH β α

4'

7f R' =

OCH3 O Ot-Bu

NH

7i R' =

α

5'

N β

β

OCH 3

NH

β α O

γ

γ

7d R' =

6' 7'

N H O β

7h R' =

H3CO

γ

2'

α

O OCH3

NH O

NH

OCH3

O H δ β O N α ε γ O O NH

Figure 2: Expanded structure of cavitand derivatives 7a-i, showing distinctive protons. Reaction of the tetra-acyl chloride cavitand with glycine ethyl ester afforded 7a in 74 % (Scheme 1).

The

1

H NMR spectrum in CDCl3 at room temperature shows signals

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characteristic of both units. Concerning the glycine unit, the signal related to the methylene protons of the ethyl ester at 4.26 ppm appears as a quartet, integrating to eight. The signal for the methyl protons of this ester at 1.30 ppm is a triplet, integrating to twelve. The signal associated with the α-protons appears as a doublet at 4.12 ppm, integrating to eight. The signal associated with the amide NH protons is deshielded and appears at 8.05 ppm as a triplet,

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integrating to four (Figure 2). The signal for the methylene protons (H6, Figure 2) of the OCH2CO group is observed as a singlet at 4.59 ppm, integrating to eight. H4 and H5 appear as a pair of doublets, both integrating to four; one at 4.48 ppm (for the inner protons, H4) and the other at 6.10 ppm (for integrating to four.

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the outer protons, H5). The aromatic cavitand protons register as a singlet at 6.87 ppm, The methine group (H2) displays a signal at 4.71 ppm as a triplet,

integrating to four. The signals related to the undecyl “feet” (R) have resolved into three

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signals: a quartet at 2.19 ppm, integrating to eight, a broad multiplet at 1.20-1.28 ppm, integrating to 72, and a triplet at 0.88 ppm, integrating to twelve. The rest of these compounds exhibited similar NMR signals and only significant features will be presented. Coupling of L-phenyl alanine methyl ester to the acyl chloride cavitand afforded compound 7c in 70 % yield (Scheme 1). The 1H NMR spectrum in CDCl3 at room temperature exhibits

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signals of both residues. The signal related to the methyl protons of the ester group appears at 3.68 ppm, integrating to twelve. Theα-protons appear at 4.97 ppm as a quartet, integrating to four. For 7c, the diastereomeric β-protons of the L-phenyl alanine unit splits into a pair of

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doublets at 3.21 ppm and 3.11 ppm, due to coupling with the α-protons (registering at 4.97 ppm as a quartet). Each of these signals integrates to four (Figure 2).

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The methylene proton signal of the OCH2CO group (H6) appears as a doublet at 4.51 ppm, integrating to eight. The signals related to H4 and H5 have undergone small changes in terms of chemical shift compared to compounds 7a-b. While both appear as doublets integrating to four, one appears at 4.26 ppm (for H4), and the other at 5.69 ppm (for H5). The change in position can be attributed to the presence of the phenyl group side chains. The 1H NMR spectroscopic data for compounds 7a-c are summarised in Table 1. The

13

C NMR signals were assigned with the aid of the HSQC spectrum and the data are

provided with the supplementary information.

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Table 1: 1H NMR data for compounds 7a-cin CDCl3 at room temperature (400 MHz).

Chemical shift/ppm (multiplicity, coupling constant, integration)

7a

7b

7c

H2

4.71 (t, J = 7.9 Hz,4)

4.62 (t,J = 5.0 Hz, 4)

4.67 (t,J = 7.9 Hz, 4)

H4

4.48 (d, J = 7.1 Hz, 4)

4.39 (d, J = 7.1 Hz, 4)

4.28 (d, J = 7.1 Hz, 4)

H5

6.10 (d, J = 7.1 Hz, 4)

6.03 (d, J = 7.1 Hz, 4)

5.69 (d, J = 7.1 Hz, 4)

H6

4.59 (s, 8)

4.50 (d, J = 5.0 Hz, 8)

4.51 (dd, J = 13.0 Hz, J =

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Proton

8.05 (t, J = 5.0 Hz, 4)

AAH*

4.26 (q, J = 7.1 Hz, 8);

8.08 (d, J = 7.6 Hz, 4)

8.06 (d, J = 8.2 Hz, 4)

4.62 (q, J = 8.56 Hz, 4); 7.10-7.19 (m, 20); 4.97 (q,

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NH

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13.0 Hz, 8)

4.12 (d, J = 5.1 Hz, 8);

3.71 (s, 12); 1.38 (d,

J = 6.3 Hz, 4); 3.68 (s, 12);

1.30 (t,J = 8.7Hz, 12)

J = 7.1 Hz, 12)

3.21 (dd, J=6.0 Hz, J=6.0

“Feet”

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Hz, 4); 3.11 (dd, J=6.4 Hz, J=6.4 Hz, 4)

2.19 (q, J = 6.5 Hz, 8);

2.07 (q, J = 6.5 Hz, 8);

1.20-1.28 (m, 72); 0.88

1.20-1.28 (m, 72); 0.84 1.20-1.28 (m, 72); 0.87 (t,

(t, J = 7.5 Hz, 12)

(t, J = 6.0 Hz, 12)

2.17 (q, J = 7.8 Hz, 8);

J = 6.3 Hz, 12)

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AAH* denotes amino acid ester peaks.

Subsequent COSY and HSQC NMR analysis confirmed the presence of the target compounds,

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showing the expected couplings between the various protons. Figure 3, displaying 1H-1H COSY couplings for compound 7c, is an example of a two-dimensional NMR experiment performed at room temperature (400 MHz). Analysis of the COSY spectrum shows that the α-protons (Phe-CH) at 4.97 ppm are coupled to the amide NH protons at 8.06 ppm as well as the β-protons (Phe-CH2) at 3.21 ppm and 3.11 ppm. The protons for H4 at 4.28 ppm are coupled to the H5 protons at 5.69 ppm. The methine protons (H2) at 4.67 ppm, which bridge the aromatic moieties, are coupled to the methylene protons of the “feet” (-CH2-) at 2.17 ppm. These protons display coupling to that of the “feet” at 1.20-1.28 ppm. The terminal methyl groups of the “feet” at 0.87 ppm are coupled to the methylene groups at 1.20-1.28 ppm.

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ACCEPTED MANUSCRIPT

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Figure 3: The COSY spectrum for compound 7c in CDCl3 at room temperature (400MHz). The β- and γ-protons of 7d appears as a multiplet at 1.60-1.67 ppm, integrating to twelve. The signal for the methyl protons attached to δ-carbon atoms is shielded and appears as a doublet at

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0.95 ppm, integrating to twenty four.

The methylene proton signal of the OCH2CO group (H6) appears as a broad singlet at 4.62

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ppm, integrating to eight. This broadening could be attributed to the slow interconversion of the leucine side chain at room temperature.29 The signals related to the H4 (4.47 ppm) and H5 protons (6.07 ppm) appear as two doublets. The signals for the β- and γ-protons of 7e appear as a multiplet at 2.00-2.14 ppm, integrating to sixteen. The δ-protons signal appears as a multiplet at 3.60 ppm, integrating to eight (Figure 2). The NH protons of the indole ring of 7f appear as a singlet at 8.71, integrating to four. The signal assigned to the tryptophan-H7’ protons appears as a doublet at 7.50 ppm, integrating to four. The signal at 7.27 ppm is a doublet that was assigned to the tryptophan-H4’protons and integrates to four. The signal assigned to the tryptophan-H5’ protons appears as a triplet at 7.10

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ppm, integrating to four. The signal at 6.98 ppm appears as a triplet and was assigned to the tryptophan-H6’protons, integrating to four, and the singlet signal at 6.98 ppm was assigned to the tryptophan-H2’protons, integrating to four. The signal for the diastereotopic methylene protons of the OCH2CO group (H6, Figure 2) appears as a pair of doublets at 4.46 ppm and 4.45 ppm, each integrating to four protons.

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The signals related to H4 and H5 of 7f have undergone changes in terms of chemical shift. They register as a pair of doublets integrating to four, one appears at 3.96 ppm (for H4), and the other at 5.19 ppm (for H5). The shift to lower frequency can be explained by the deshielding nature of the carbonyl groups in OCH2CO. The cavitand aromatic rings were affected by the

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presence of the indole ring. The 1H NMR data for compounds 7d-fare summarised in Table 2. Table 2: 1H NMR data for compounds 7d-fin CDCl3 at room temperature (400 MHz).

4.70 (t, J = 7.5 Hz, 4) 4.68 (t,J = 7.9 Hz, 4) 4.47 (d, J = 7.1 Hz, 4) 4.41 (d, J =6.9 Hz,4) 6.07 (d, J = 7.1 Hz, 4) 5.75 (d, J = 7.0 Hz,4) 4.62 (br s, 8) 4.58 (br s, 8) 8.09 (d, J = 8.4 Hz, 4) 4.70 (q, J = 3.56 Hz, 4); 4.54 (q, J = 5.64 Hz, 4); 3.76 (s, 12); 1.60-1.67 3.71 (s, 12); 3.50-3.85(m, (m, 12); 0.95 (d, J = 7.0 8); 2.00-2.14 (m, 16) Hz, 24)

2.19 (q,J = 6.7 Hz, 8); 2.14 (q,J = 6.2 Hz, 8); 1.20-1.28 (m, 72); 0.88 1.20-1.29 (m, 72); 0.88 (t, J = 7.1 Hz, 12) (t, J = 6.5 Hz, 12) AAH* denotes amino acid ester peaks.

AC C

Feet

7e

TE D

H2 H4 H5 H6 NH AAH*

7d

EP

Proton

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Chemical shift/ppm (multiplicity, coupling constant, integration) 7f

4.53 (t, J = 8.0 Hz 4) 3.96 (d, J = 7.1 Hz, 4); 5.19 (d, J = 7.1 Hz, 4); 4.46 (d, J = 15.8 Hz, 4); 7.80 (d, J = 8.0 Hz, 4) 8.71 (s, 4); 7.50 (d, J = 7.9 Hz, 4); 7.27 (d, J = 7.9 Hz, 4); 7.10 (t, J = 7.4 Hz, 4); 6.98 (t, J = 7.5 Hz, 4); 6.98 (s, 4); 5.09 (q, J = 7.1 Hz, 4); 3.71 (s, 12); 3.303.40(m, 8) 2.10 (q,J = 7.7 Hz, 8); 1.20-1.28 (m, 72); 0.87 (t, J = 6.5 Hz, 12)

The signal related to the t-butyl protons, which protects the carboxylic group of 7g, is a singlet at 1.48 ppm, integrating to thirty six. The t-butyl ether proton signals are registered at 1.15 ppm as a singlet, integrating to thirty six. The methylene proton signal of the OCH2CO group (H6) appears as a pair of doublets at 4.61 ppm and 4.45 ppm, each of these signals integrates to four. This splitting can be attributed to the non-equivalency of the methylene protons affected by the presence of the t-butyl groups in close proximity of the chiral α-carbon. The signals for H4 and H5 appear as a pair of doublets, one at 4.52 ppm (for H4), and the other at 6.09 ppm (for H5).

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The signal associated with the methyl protons of ester 7h, which protect the carboxylic group is a singlet at 3.80 ppm, integrating to twelve. Theα-protons of this amino acid register at 4.72 ppm as a quartet, integrating to four. The signal related to the β-protons appears as two multiplets at 2.13 ppm and 2.20 ppm due to coupling with the α-protons. The γ-proton signal of this acid appears as a multiplet at 2.42 ppm, integrating to eight. The methyl proton signal

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of the protecting group appears as a singlet at 3.61 ppm. The signals for 7i related to the aromatic protons of the Cbz (carboxybenzyl) group and the benzyl ester group (Bn) appear as a multiplet at 7.23-7.43 ppm, integrating to forty. The signal for the methylene protons of the Cbz groups, which protects the amine group at the side chain,

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appears as a doublet at 5.09 ppm due to coupling with the α-protons, and the one associated with the benzyl ester group appears as a singlet at 4.99 ppm. The signals related to the γ- and

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δ-protons are multiplets at 1.39 ppm, integrating to 16. The signal for the ε-protons appears as a quartet at 3.04 ppm, integrating to eight. summarised in Table 3.

The 1H NMR data for compounds 7g-i are

Table 3: 1H NMR data for compounds 7g-iin CDCl3 at room temperature (400 MHz). Chemical shift/ppm (multiplicity, coupling constant, integration) 7d

7e

7f

TE D

Proton

4.72 (t,J = 8.0 Hz, 4) 4.52 (d,J = 7.1 Hz, 4) 6.09 (d, J = 7.1 Hz, 4) 4.61 (d, J = 15.8 Hz, 4); 8.23 (d, J = 8.6 Hz, 4)

4.72 (t, J = 7.2 Hz, 4) 4.71 (t, J = 7.2 Hz, 4) 4.48 (d, J = 6.8 Hz, 4) 4.39 (d, J = 7.0 Hz, 4) 6.12 (d, J = 6.8 Hz, 4) 6.00 (d, J = 7.0 Hz, 4) 4.59 (d, J = 5.0 Hz, 8) 4.50 (d, J = 16.0 Hz, 4)) 8.22 (d, J = 7.7 Hz, 4) 8.07 (d, J = 8.0 Hz, 4)

4.72 (q, J = 5.72 Hz, 4); 3.84 4.72 (q, J = 8.56 Hz, 8); 7.23-7.43 (m, 40); (dd, J = 3.1 Hz, J = 3.1 Hz 4); 3.80 (s, 12); 3.61 (s, 12); 5.09 (d, J = 12.3 Hz, 3.54 (dd, J = 2.6 Hz, J = 2.52 2.30-2.50(m, 8); 1.90-2.20 8); 4.99 (s, 8); 4.65Hz, 4); 1.48 (s, 36); 1.15 (s, 36) (m, 4); 1.90-2.20 (m, 4) 4.75(m, 4); 3.04 (q, J = 5.2 Hz, 8); 1.751.85(m, 4); 1.851.90(m, 4); 1.30-1.40 (m, 16) Feet 2.17 (q,J = 6.4 Hz, 8); 2.19 (q,J = 5.1 Hz, 8); 2.10 (q, J = 6.8 Hz, 8); 1.20-1.28 (m, 72); 1.20-1.28 (m, 72); 1.20-1.28 0.87 (t,J = 6.5 Hz, 12) 0.89 (t, J = 6.5 Hz, 12) (m, 72); 0.83 (t,J = 6.7 Hz 12) AAH* denotes amino acid ester peaks.

AC C

AAH*

EP

H2 H4 H5 H6 NH

To investigate the splitting pattern of the methylene protons of the OCH2CO group (H6, Figure 2), high temperature 1H NMR experiments were recorded for compound 7f in d6-DMSO at 600

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MHz from 25 ºC to 90 ºC as an example for these compounds. At 25 ºC, the 1H NMR spectrum of this compound (Figure 4) maintains the respective signal multiplicity and integration. The signal related to the diastereotopic β-protons are split into a pair of doublets at 3.39 ppm and 3.36 ppm due to coupling with the α-protons. All protons have experienced small changes in terms of chemical shifts compared to the

EP

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SC

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spectrum in CDCl3 at room temperature.

AC C

Figure 4:1H NMR spectrum of compound 7f (600 MHz, DMSO-d6); the methylene (OCH2CO) peak is assigned at 25 ºC.

At 60 ºC, all signals were sharpened (Figure 5), which indicates that rotation around the bonds increased. The signal related to the methylene protons of the OCH2CO group appears as a doublet at 4.52 ppm, integrating to eight protons.

The remaining signals maintain their

respective multiplicity and integration as seen in Figure 4.

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ACCEPTED MANUSCRIPT

Figure 5: 1H NMR spectrum of 7f (600 MHz, DMSO-d6); the methylene (OCH2CO) peak is assigned at 60 ºC.

TE D

Importantly, when compound 7f was heated in d6-DMSO at 90 ºC, further sharpening of the signals was observed. The amide NH protons signal experienced shielding and the signal associated with the methylene protons (H6, Figure 2) appears as a singlet at 4.53 ppm, integrating to eight protons as seen in Figure 6. Thus, as the temperature increased, the

EP

coalescence of the methylene protons signal is observed. This observation can be attributed to

AC C

the increase in the molecular motions which overcome hindrance to bond rotation.30

14

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

Figure 6: Section of the 1H NMR spectrum of 7f (600 MHz, DMSO-d6); the methylene (OCH2CO) peak is assigned at 90 ºC.

TE D

Conclusion

Amphiphilic cavitands 7a-I appended with four amino acid moieties at the upper rim and four undecyl chains at the lower rim were prepared. These compounds were isolated in reasonable yields (58-74%) by connecting nine amino acid moieties to the four acetic acid residues

EP

appended to the upper rim of cavitand 6 in dry methylene chloride in the presence of Et3N. The structures of these compounds were established based on one- and two-dimensional NMR

AC C

experiments, and confirmed by infrared (IR) and mass spectral(MS) analysis. The 1H NMR spectra are generally simple in CDCl3 at room temperature which verified that all tetrasubstituted cavitands have symmetrical C4v conformation structures. High temperature NMR experiments confirmed the stability of these conformations (rigidity). The 1H NMR data in non-polar solvent (CDCl3) shows that the signal associated with the amide protons appear deshielded, indicating the involvement of these protons in hydrogen bonding, except for compound 7e.

15

ACCEPTED MANUSCRIPT Experimental

Starting materials obtained from commercial suppliers were used without further purification unless otherwise stated. Air- or moisture-sensitive reactions were performed using oven-dried glassware under an inert atmosphere of dry nitrogen. Tetrahydrofuran (THF) was distilled from sodium benzophenoneketyl and dichloromethane was distilled from calcium hydride. Dimethyl

RI PT

sulfoxide (DMSO) and dimethylformamide (DMF) were stored over 4Å molecular sieves prior to use. Thin layer chromatography (TLC) was performed on aluminium-backed, pre-coated silica gel plates (Merck, silica gel 60 F254, 20 cm x 20 cm). Mobile phases are reported as volume ratios or volume percents. Compounds were visualized using UV light, p-anisaldehyde,

SC

or iodine stains. Column chromatography was performed on silica gel 60 (Merck, particle size 0.040-0.063 mm). Eluting solvents are reported as volume ratios or volume percents. Melting points were recorded and are uncorrected.1H NMR spectra were recorded on a 400 MHz Bruker

M AN U

AVANCE III or 600 MHz Bruker Ultrashield spectrometer, the chemical shifts were referenced to the solvent peak, namely δ= 7.24 ppm for CDCl3,δ=2.50 ppm for (CD3)2SO and δ=2.05 ppm for (CD3)2CO at ambient temperature. The 1H NMR spectra were recorded ata transmitter frequency of 600.1 MHz (spectral width, 12335.5 Hz; acquisition time, 1.328 s;90opulse width, 15 µs; scans, 16; relaxation delay, 1.0 s)for the Bruker AVANCE III 600 instrument while the 1

H NMR spectra were recorded at a transmitter frequency of 400.2 MHz (spectral width, 8223.7

TE D

Hz; acquisition time, 3.98 s; 90o pulse width, 10 µs;scans, 16; relaxation delay, 1.0 s) for the Brucker AVANCE III 400 instrument. The

13

C NMR spectra were recorded at 150.9 MHz

(spectral width, 36057.7 Hz; acquisition time, 0.908 s; 0.908 s, 90o pulse width, 9.00 µs;scans, 13

C NMR

EP

4800; relaxation delay, 2.00s) for the Bruker AVANCE III 600instrument while the

spectra were recorded at 100.6 MHZ(spectral width, 24038.5 Hz; acquisition time, 1.363 s;90o

AC C

pulse width, 8.40 µs, scans,3200;relaxation delay, 2.00 s) for the Bruker AVANCE III 400 instrument.

The 2D experimental data parameters obtained on the Bruker AVANCE III 400 were as follows: 90o pulse width, 10µs for all spectra, spectral width for 1H, 3731.3, 3521.1, 3401.3, 3676.4, 3125.0 and 4065.0, 4065.0, 3731.3, 3546.1 Hz for 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h and 7i, respectively, (COSY and HSQC) spectral width for 13C, 166670.4 Hz (HSQC) for 7a-i, number of data points per spectrum, 2048 (COSY), 1024 (HSQC) for compounds 7a-i; number of time incremental spectra 128 (COSY), 256 (HSQC) for compounds 7a-i; relaxation delays for compounds for compounds 7a, 7f, 7g, 7h and 7i was 1.4s and 7b, 7c, 7d and 7e was 1.3s for COSY experiments while the relaxation delay for HSQC experiments had 1.4s for 7a-i respectively. Data are reported as positions in parts per million (δ in ppm), multiplicity (s = singlet, d = doublet, dd = double of doublets, t = triplet, q = quartet, m = multiplet, br = broad),

16

ACCEPTED MANUSCRIPT coupling constant (J in Hz) and integration (number of protons).

13

C NMR spectra were

recorded on a 400 MHz Bruker AVANCE (100 MHz) or 600 MHz BrukerUltrashield spectrometer (150 MHz). Data are reported as positions in parts per million (δ in ppm). Optical rotation data was acquired on a Perkin Elmer Model 341 Polarimeter using a 1 mL cell with a path length of 100 mm. Infrared (IR) spectra were recorded on a Perkin Elmer spectrum 100 instrument with a universal attenuated total reflection (ATR) attachment at room temperature.

RI PT

Wave numbers are reported in units of cm-1. Mass spectra were recorded using a Bruker micrOTOF-Q II Electron Spray Ionization (ESI) Mass Spectrometer (MS).

5,11,17,23-Tetrabromo- 2,8,14,20-tetraundecyl-pentacyclo[19.3.1.13,7.19,13.115,19]octacosa-

SC

1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene-4,6,10,12,16,18,22,24-octol, Stereoisomer (2)31,32

M AN U

To a stirring solution of octol, 1, (55 g, 50 mmol) in 2-butanone (300 mL) was added Nbromosuccinimide (NBS) (42.70 g, 240 mmol) over 30 minutes; the temperature was maintained below 25 ºC by cooling on an ice-bath. Once addition was complete, the resulting solution was stirred for 18 hours at 25 ºC in the dark under a nitrogen atmosphere, then poured directly into boiling methanol (1.00 L) to remove excess succinimide, reheated to boiling, and filtered while hot. The solid was washed with hot methanol and dried, to yield compound 8, as an off-white

TE D

powder. The compound was pure enough for use in subsequent reactions. (62 g, 87 %); mp 286289 ºC [Literature mp >265-275 ºC (dec)];31,32 1H NMR [acetone-d6, 400 MHz]: δ = 8.28 (s, 8 H, ArOH), 7.60 (s, 4 H, ArH), 4.45 (t, 4 H, CH (methine)), 2.30 (q, 8 H, CH2(CH2)9CH3), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 0.89 (t, 12 H, CH3) ppm;

13

C NMR [acetone-d6, 100 MHz]: δ =

EP

150.05, 126.01, 124.49, 101.21, 36.43, 34.56, 32.69, 30.55, 29.82, 29.63, 29.44, 29.25, 28.84, 23.36, 14.38 ppm; FT-IR/ATR: 3383, 2921, 2851, 1664, 1535, 1468, 1434, 1313, 1246, 1151,

AC C

1088, 968, 773, 720, 644, 579, 438 cm-1. 7,11,15,18-Tetrabromo-1,21,23,25-tetraundecyl-2,20:3,19-dimetheno-1H,21H,23H,25Hbis[1,3] dioxocino[5,4-i:5’,4’-i’] benzo[1,2-d:5,4-d’]-bis[1,3]benzodioxocin, Stereoisomer (3)33 To a solution of octol, 2 (42.50 g, 30 mmol) and oven-dried (110 ºC) K2CO3 (62.10 g, 450 mmol) in dry degassed DMF (800 mL), bromochloromethane (29.30 mL, 450 mmol) was added over 30 minutes. The mixture was refluxed at 65 ºC under a nitrogen atmosphere. After 24 hours, more bromochloromethane (4 mL, 60 mmol) was added. After 48 hours, the DMF was removed in vacuo to give a dark brown gum. The residue was dissolved in diethyl ether (250 mL), and then 2M HCl (400mL) was slowly added with stirring to neutralise K2CO3. After stirring the mixture for 20 minutes, the ether phase was collected and the aqueous phase was extracted with more ether. The combined ether phases were washed with saturated brine, then

17

ACCEPTED MANUSCRIPT

dried over anhydrous MgSO4, and filtered. The diethyl ether was evaporated to give a clear brown gum. The crude gum was purified on silica gel chromatography by using hexanedichloromethane (1:1) as a mobile phase. The eluent was concentrated with a rotary evaporator to give a cream-coloured residue. Trituration of this residue with methanol yielded a creamcoloured solid, which was re-crystallized from THF-methanol (1:1) to yield the title compound as white solid (31.70 g, 72 %); mp 74-76 ºC [Literature mp 80-83 ºC]; 1H NMR [CDCl3, 400

RI PT

MHz]: δ = 7.02 (s, 4 H, ArH), 5.96 (d, J = 7.4 Hz, 4 H, outer of OCH2O), 4.84 (t, J = 8.1 Hz, 4 H, CH (methine)), 4.39 (d, J = 7.4 Hz, 4 H, inner of OCH2O), 2.30 (q, 8 H, CH2(CH2)9CH3), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 0.88 (t, 12 H, CH3) ppm; 13C NMR [CDCl3, 100 MHz]: δ = 152.05, 139.28, 119.07, 113.51, 98.48, 37.63, 31.94, 29.87, 29.70, 29.68, 29.40, 27.73, 25.61,

SC

22.70, 14.12 ppm; FT-IR/ATR: 2921, 2851, 1466, 1450, 1416, 1299, 1228, 1181, 1091, 960, 790, 728, 650, 619, 581 cm-1.

M AN U

1,21,23,25-Tetraundecyl-2,20:3,19-dimetheno-1H,21H,23H,25H-bis[1,3]dioxocino[5,4-i:5’,4’i’]benzo[1,2-d:5,4-d’]-bis[1,3]benzodioxocin-7,11,15,18-tetrol, Stereoisomer (4)34,35 A solution of vacuum-dried, 3 (15 g, 10.20 mmol) in dry THF (900 mL) was set to stir in an oven-dried round-bottomed flask under a nitrogen atmosphere, sealed with a septum. The solution was cooled to -78 ºC, and treated with n-butyllithium (1.6 M solution in hexane, 96 mL,

TE D

153 mmol), which was slowly added via a septum using a syringe over 30 minutes. After 20 minutes, trimethylborate (34.20 mL, 306 mmol) was added slowly over 15 minutes, so turning the solution into a yellow emulsion. The flask and its contents were removed from the cooling bath, and allowed to attain room temperature slowly, during which time the emulsion

EP

disappeared to yield a yellow solution. After stirring at room temperature for two hours, the solution was again cooled to -78 ºC, and treated with a 1:1 mixture of 15% H2O2 and 1.5 M

AC C

NaOH (300 mL) to give a viscous, white mixture. The solution was allowed to warm to room temperature and stirred for 18 hours. Na2S2O5 (60 g) was carefully added to the stirring solution, resulting in the formation of two layers. The THF layer was subsequently removed in vacuo to yield a yellow solid in the residual water, which was filtered and air-dried. The mixture of alcohols was pre-adsorbed onto silica before chromatography on silica. The chromatography column was gradient eluted, starting with 1:2 ethyl acetate-hexane, accompanied by slow addition of ethyl acetate towards a final ethyl acetate-hexane ratio of 8:2. The title compound was exclusively isolated as the most polar fraction (Rf = 0.30, by TLC in 8:2 ethyl acetate : hexane) and found to be pure. (6.60 g, 53 %); mp 188-190 ºC [Literature mp 190-192 ºC];34,35 1H NMR [CDCl3, 400 MHz]: δ = 6.60 (s, 4 H, ArH), 5.94 (d, J = 6.9 Hz, 4 H, outer of OCH2O), 5.35 (s, 4 H, ArOH), 4.68 (t, J = 8.1 Hz, 4 H, CH (methine)), 4.42 (d, J = 6.9 Hz, 4 H, inner of OCH2O), 2.20 (q, 8 H, CH2(CH2)9CH3), 1.20-1.30 (m, 72 H, CH2(CH2)9CH3), 0.88 (t, 12 H,

CH3) ppm;

13

18

ACCEPTED MANUSCRIPT

C NMR [CDCl3, 100 MHz]: δ = 141.95, 140.77, 138.52, 110.17, 99.79, 36.79,

31.94, 29.84, 29.76, 29.72, 29.60, 29.40, 27.86, 22.70, 14.12 ppm; FT-IR/ATR: 3425, 2921, 2851, 1588, 1465,1444, 1319, 1242, 1152, 1097, 975, 721, 685, 590, 515 cm-1. 7,11,15,18-Tetrakis[(methoxycarbonyl)methoxy]-1,21,23,25-tetraundecyl-2,20:3,19dimetheno-1H,21H,23H,25H-bis[1,3]dioxocino[5,4-i:5’,4’-i’]benzo[1,2-d:5,4-d’]-

RI PT

bis[1,3]benzodioxocin, Stereoisomer(5)24,25 To a stirring solution of tetrol, 4 (3.10 g, 2.55 mmol) and oven-dried (110 ºC) K2CO3 (3.50 g, 25.50 mmol) in dry CH3CN (350 mL), methyl-2-bromoacetate (1.50 mL, 12.75 mmol) was added and the reaction mixture refluxed at 82 ºC for 24 hours under a nitrogen atmosphere, then

SC

the reaction mixture was cooled to room temperature and the solvent was removed in vacuo. The residue was dissolved in CH2Cl2 (200 mL). The organic layer was washed with 1M HCl

M AN U

(50 mL) followed by water (100 mL, 3 times), and then washed with saturated brine (100 mL), and dried over anhydrous MgSO4. After filtration, the solution was evaporated under reduced pressure to yield the title compound, which was triturated with methanol to give a white solid. (3.80 g, 98 %); mp 184-187ºC [Literature mp 188-190 ºC];24,25 1H NMR [CDCl3, 400 MHz]: δ = 6.77 (s, 4 H, ArH), 5.70 (d, J = 7.4 Hz, 4 H, outer of OCH2O), 4.67 (t, J = 8.0 Hz, 4 H, CH (methine)), 4.52 (s, 8 H, ArOCH2), 4.39 (d, J = 7.4 Hz, 4 H, inner of OCH2O), 3.76 (s, 12 H,

ppm;

13

TE D

OCH3), 2.18 (q, 8 H, CH2(CH2)9CH3), 1.20-1.30 (m, 72 H, CH2(CH2)9CH3), 0.88 (t, 12 H, CH3) C NMR [CDCl3, 100 MHz]:δ = 169.75, 147.35, 143.93, 138.86, 114.37, 99.91, 69.99,

51.91, 36.85, 31.94, 29.90, 29.86, 29.75, 29.72, 29.41, 27.41, 22.69, 14.11 ppm; FT-IR/ATR: cm-1.

EP

2919, 2851, 1758, 1737, 1576, 1444, 1365, 1293, 1207, 1132, 1081, 972, 741, 720, 686, 587

AC C

7,11,15,18-Tetrakis[(hydroxycarbonyl)methoxy]-1,21,23,25-tetraundecyl-2,20:3,19dimetheno-1H,21H,23H,25H-bis[1,3]dioxocino[5,4-i:5’,4’-I’]benzo[1,2-d:5,4-d’]bis[1,3]benzodioxocin, Stereoisomer(6)24,25 To a solution of compound 5 (1.5 g, 1.0 mmol) in THF (70 mL) was added 2M KOH (30 mL), and the reaction mixture was stirred at room temperature for 24 hours. The reaction mixture was acidified with 2M HCl (60 mL), and the THF layer was removed in vacuo. The precipitate was filtered and thoroughly washed with water. The solid obtained was dried at 80 ºC under vacuum for 3 hours, and then suspended in THF solvent and filtered.

The solution obtained was

evaporated to dryness to yield the title compound as a white solid. (1.38 g, 96 %); mp 214-216 º

C [Literature mp 218-220 ºC];24,25 1H NMR [DMSO-d6, 400 MHz]: δ = 7.23 (s, 4 H, ArH), 5.70

(d, J = 7.5 Hz, 4 H, outer of OCH2O), 4.54 (t, J = 7.9, 4 H, CH (methine)), 4.44 (s, 8 H, ArOCH2), 4.27 (d, J = 7.5 Hz, 4 H, inner of OCH2O), 2.29 (q, 8H, CH2(CH2)9CH3), 1.20-1.30

19

ACCEPTED MANUSCRIPT (m, 72 H, CH2(CH2)9CH3), 0.87 (t, 12 H, CH3) ppm;

C NMR [DMSO-d6, 100 MHz]: δ =

13

171.95, 146.24, 143.44, 138.63, 115.38, 99.62, 69.40, 36.86, 31.30, 29.20, 29.05, 28.73, 27.64, 22.06, 21.00, 13.86 ppm; FT-IR/ATR: 3353, 3182, 2922, 2852, 1665, 1535, 1445, 1346, 1316, 1225, 1149, 1052, 966, 762, 687, 587, 438 cm-1. General procedure for the synthesis of amino acid-cavitand derivatives(7a-i)26-28

RI PT

To a suspension of 6(0.50 g, 0.35 mmol) in dry CH2Cl2 (20 mL) was added freshly distilled oxalyl chloride (0.60 mL, 7.00 mmol), and the mixture was refluxed for 18 hours under a nitrogen atmosphere. The unreacted oxalyl chloride and solvent were removed in vacuo, and the product obtained was dried under vacuum for 1 hour. Subsequently, it was dissolved in dry

SC

CH2Cl2 (10 mL), and slowly added to a cooled solution (0 ºC) of amino acid ester hydrochloride (1.75 mmol) and triethylamine (Et3N) (0.25 mL, 1.75 mmol) in dry CH2Cl2 (20 mL). The

M AN U

reaction mixture was allowed to warm up to room temperature and stirred under a nitrogen atmosphere for 18 hours. The solution mixture was treated with 1M HCl (20 mL), and the organic layer was separated, washed with water (30 mL), and brine (30 mL). The organic layer was dried over anhydrous Na2SO4. The solution was filtered, and the solvent was removed under vacuum pressure, yielding a sticky residue. The residue obtained was purified on silica gel chromatography using 3% methanol in chloroform as a mobile phase.

The fractions

TE D

collected were concentrated with a rotary evaporator to give a white residue. Methanol was added to precipitate the purified products.

7,11,15,28-Tetrakis[((O-ethyl-L-glycinyl)carbonyl)methoxy]-1,21,23,25-tetraundecyl

EP

cavitand(7a)

Glycine ethyl ester hydrochloride (0.25 g, 1.75 mmol) was used as in the general procedure.

AC C

White solid. (0.46 g, 74 %), Rf = 0.40 (3 % MeOH/CH3Cl), mp 87-90ºC; 1H NMR [CDCl3, 400 MHz]: δ = 8.05 (t,J = 5.0 Hz, 4 H, NH), 6.87 (s, 4 H, ArH), 6.10 (d, J = 7.1 Hz, 4 H, outer of OCH2O), 4.71 (t, J = 7.9 Hz, 4 H, CH (methine)), 4.59 (s, 8 H, ArOCH2), 4.48 (d, J = 7.1 Hz, 4 H, inner of OCH2O), 4.26 (q,J = 7.1 Hz, 8 H, COOCH2CH3), 4.12 (d, J = 5.1 Hz, 8 H, GlyCH2), 2.19 (q,J = 6.5 Hz, 8 H, CH2(CH2)9CH3), 1.30 (t, J = 8.7 Hz, 12 H, COOCH2CH3), 1.201.28 (m, 72 H, CH2(CH2)9CH3), 0.88 (t,J = 7.5 Hz, 12 H, CH3) ppm; 13C NMR [CDCl3, 100 MHz]: δ = 170.12, 169.67, 146.96, 143.96, 139.10, 114.85, 99.66, 72.97, 61.64, 41.02, 40.88, 36.98, 31.94, 29.93, 29.74, 29.72, 29.41, 27.92, 22.69, 14.18, 14.11 ppm; FT-IR/ATR: 3365, 2918, 2850, 1738, 1679, 1526, 1468, 1444, 1374, 1316, 1206, 1152, 1101, 1017, 967, 718, 686, 587 cm-1; MS (ESI-TOF) Calculated for C100H148O24N4Na [M+Na]+: m/z = 1813.0409, Found: m/z = 1813.0387.

20

ACCEPTED MANUSCRIPT 7,11,15,28-Tetrakis[((O-methyl-L-alaninyl)carbonyl)methoxy]-1,21,23,25-tetraundecyl cavitand(7b) L-Alanine

methyl ester hydrochloride (0.25 g, 1.75 mmol) was used as in the general

procedure. White solid. (0.42 g, 68 %); Rf = 0.42 (3 % MeOH/CH3Cl); mp 76-79ºC; [α]20D = +41.67 (c = 1.20, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.08 (d, J = 7.6 Hz, 4 H, NH), 6.81

RI PT

(s, 4 H, ArH), 6.03 (d, J = 7.1 Hz, 4 H, outer of OCH2O), 4.62 (t, J = 5.0 Hz,4 H, CH (methine)), 4.62 (q, J = 8.5 Hz, 4 H, Ala-αH), 4.50 (d, J = 5.0 Hz, 8 H, ArOCH2), 4.39 (d, J = 7.1 Hz, 4 H, inner of OCH2O), 3.71 (s, 12 H, OCH3), 2.07 (q,J = 6.5 Hz,J = 7.1 Hz, 8 H, CH2(CH2)9CH3), 1.38 (d, J = 7.1 Hz, 12 H, Ala-CH3), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3),

SC

0.84 (t,J = 6.0 Hz, 12 H, CH3) ppm; 13C NMR [CDCl3, 100 MHz]: δ = 173.24, 168.66, 147.03, 146.81, 143.98, 139.30, 138.88, 114.83, 99.64, 73.05, 52.52, 47.64, 36.91, 31.94, 29.86, 29.74, 29.72, 29.40, 27.87, 22.69, 18.56, 14.11 ppm; FT-IR/ATR: 3355, 2923, 2852, 1742, 1680,

M AN U

1524, 1445, 1315, 1210, 1151, 1052, 1017, 967, 854, 720, 686, 588, 548 cm-1; MS (ESI-TOF) Calculated for C100H148O24N4Na [M+Na]+: m/z = 1813.0409, Found: m/z = 1813.0458. 7,11,15,28-Tetrakis[((O-methyl-L-phenylalaninyl)carbonyl)methoxy]-1,21,23,25tetraundecyl cavitand(7c)

methyl ester hydrochloride (0.38 g, 1.75 mmol) was used as in the general

TE D

L-Phenylalanine

procedure. White solid. (0.51 g, 70 %); Rf = 0.52 (3 % MeOH/CH3Cl); mp 72-74ºC; [α]20D = +36.36 (c = 1.10, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.06 (d, J = 8.2 Hz, 4 H, NH), 7.10-7.19 (m, 20 H, Phe-ArH). 6.82 (s, 4 H, ArH), 5.69 (d, J = 7.1 Hz, 4 H, outer of OCH2O),

EP

4.97 (q, J = 6.3 Hz,4 H,Phe-αH), 4.67 (t,J = 7.9 Hz, 4 H, CH (methine)), 4.51 (dd, J = 13.0 Hz,J = 13.0 Hz, 8 H, ArOCH2), 4.28 (d, J = 7.1 Hz, 4 H, inner of OCH2O), 3.68 (s, 12 H,

AC C

OCH3), 3.21 (dd,J = 6.0 Hz,J = 6.0 Hz, 4 H, Phe-ArCH2), 3.11 (dd, J = 6.4 Hz,J = 6.4 Hz,4 H, Phe-ArCH2), 2.17 (q,J = 7.8 Hz, 8 H, CH2(CH2)9CH3), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 0.87 (t,J = 6.3 Hz, 12 H, CH3) ppm; 13C NMR [CDCl3, 100 MHz]: δ = 171.80, 168.59, 146.96, 146.68, 143.89, 139.15, 138.88, 135.92, 129.32, 128.40, 126.97, 114.70, 99.30, 72.85, 52.93, 52.34, 38.42, 36.93, 31.93, 29.97, 29.80, 2976, 29.71, 29.41, 28.01, 22.69, 14.11 ppm; FTIR/ATR: 3355, 2923, 2852, 1742, 1680, 1524, 1446, 1315, 1210, 1151, 1051, 1017, 967, 720, 686, 588, 549 cm-1.

MS (ESI-TOF) Calculated for C124H164O24N4Na[M+Na]+: m/z =

2117.1661, Found: m/z = 2117.1660.

21

ACCEPTED MANUSCRIPT 7,11,15,28-Tetrakis[((O-methyl-L-leucinyl)carbonyl)methoxy]-1,21,23,25-tetraundecyl cavitand(7d) L-Leucine

methyl ester hydrochloride (0.32 g, 1.75 mmol) was used as in the general

procedure. White solid. (0.48 g, 70 %); Rf = 0.52 (3 % MeOH/CH3Cl); mp 68-71ºC; [α]20D = +66.67 (c = 1.10, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.09 (d, J = 8.4 Hz, 4 H, NH), 6.86

RI PT

(s, 4 H, ArH), 6.07 (d, J = 7.1 Hz, 4 H, outer of OCH2O), 4.70 (t,J = 7.5 Hz, 4 H, CH (methine)), 4.70 (q, J = 3.56 Hz , 4 H, Leu-αH), 4.62 (br s, 8 H, ArOCH2), 4.47 (d, J = 7.1 Hz, 4 H, inner of OCH2O), 3.76 (s, 12 H, OCH3), 2.19 (q,J = 6.7 Hz, 8 H, CH2(CH2)9CH3), 1.601.67 (m, 12 H, Leu-CH and Leu-CH2), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 0.95 (d,J = 7.0

SC

Hz, 24 H, Leu-CH3), 0.88 (t,J = 7.1 Hz, 12 H, CH3) ppm; 13C NMR [CDCl3, 100 MHz]: δ = 173.22, 168.79, 147.03, 146.67, 143.80, 139.40, 138.79, 114.80, 99.62, 72.87, 52.30, 50.26,

M AN U

41.75, 37.01, 31.92, 29.96, 29.89, 29.39, 27.94, 24.84, 22.97, 22.85, 22.67, 22.02, 14.09, 14.03 ppm; FT-IR/ATR: 3365, 2918, 2850, 1738, 1678, 1527, 1468, 1445, 1374, 1316, 1206, 1153, 1054, 1017, 968, 860, 807, 718, 686, 587 cm-1.

MS (ESI-TOF) Calculated for

C112H172O24N4Na [M+Na]+: m/z = 1981.2287, Found: m/z = 1981.2171. 7,11,15,28-Tetrakis[((O-methyl-L-prolinyl)carbonyl)methoxy]-1,21,23,25-tetraundecyl

L-Proline

TE D

cavitand(7e)

methyl ester hydrochloride (0.30 g, 1.75 mmol), was used as in the general

procedure. White solid. (0.43 g, 65 %); Rf = 0.33 (3 % MeOH/CH3Cl); mp 78-81ºC;[α]20D = −40.48 (c = 1.30, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 6.79 (s, 4 H, ArH), 5.75 (d,J = 7.0

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Hz, 4 H, outer of OCH2O), 4.68 (t,J = 7.9 Hz, 4 H, CH (methine)), 4.58 (br s, 8 H, ArOCH2), 4.54 (q,J = 5.64 Hz, 4 H, Pro-αH), 4.41 (d, J = 6.9 Hz, 4 H, inner of OCH2O), 3.71 (s, 12 H,

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OCH3), 3.50-3.85 (m, 8 H, Pro-δH), 2.14 (q, J = 6.2 Hz, 8 H, CH2(CH2)9CH3), 2.00-2.14 (m, 4 H, Pro-βH), 2.00-2.14 (m, 4 H, Pro-βH), 2.00-2.14 (m, 8 H, Pro-γH), 1.20-1.29 (m, 72 H, CH2(CH2)9CH3), 0.88 (t, J = 6.5 Hz, 12 H, CH3) ppm;

13

C NMR [CDCl3, 100 MHz]: δ =

172.58, 167.04, 147.59, 143.92, 138.86, 114.38, 99.99, 72.14, 59.01, 52.29, 46.86, 36.90, 31.95, 31.49, 29.98, 29.92, 29.75, 29.41, 28.84, 27.97, 24.94, 21.95, 14.12 ppm; FT-IR/ATR: 3364, 2918, 2850, 1738, 1677, 1527, 1445, 1316, 1206, 1153, 1055, 1017, 968, 860, 807, 718, 686, 587 cm-1. MS (ESI-TOF) Calculated for C108H156O24N4Na[M+Na]+: m/z = 1917.1035, Found: m/z = 1917.0982.

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methyl ester hydrochloride (0.45 g, 1.75 mmol), was used as in the general

procedure. White solid. (0.48 g, 61 %), Rf = 0.36 (3 % MeOH/CH3Cl), mp 110-113ºC; [α]20D = +38.46 (c = 1.30, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.71 (s, 4 H, NH-Indole), 7.80

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(d, J = 8.0 Hz, 4 H, NH), 7.50 (d,J = 7.9 Hz, 4 H, H7-Indole), 7.27 (d, J = 7.9 Hz, 4 H, H4Indole), 7.10 (t,J = 7.4 Hz, 4 H, H5-Indole), 6.98 (t,J = 7.5 Hz, 4 H, H6-Indole), 6.98 (s, 4 H, H2-Indole), 6.73 (s, 4 H, ArH), 5.19 (d, J = 7.1 Hz,4 H, outer of OCH2O), 5.09 (q,J = 7.1 Hz,4 H, Trp-αH), 4.53 (t,J = 8.0 Hz 4 H, CH(methine)), 4.46 (d, J = 15.8 Hz, 4 H, ArOCH2), 4.45

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(d, J = 15.8 Hz, 4 H, ArOCH2), 3.96 (d, J = 7.1 Hz, 4 H, inner of OCH2O), 3.71 (s, 12 H, OCH3), 3.30-3.40 (m, 8 H, Trp-βH), 2.10 (q,J = 7.7 Hz, 8 H, CH2(CH2)9CH3), 1.20-1.28 (m, 72 C NMR [CDCl3, 100 MHz]: δ =

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H, CH2(CH2)9CH3), 0.87 (t,J = 6.5 Hz, 12 H, CH3) ppm;

172.52, 168.87, 146.87, 143.37, 138.94, 138.80, 136.13, 127.62, 122.80, 122.14, 119.54, 118.46, 114.59, 111.30, 109.59, 99.08, 72.45, 52.54, 52.52, 36.79, 31.94, 29.93, 29.82, 29.76, 29.74, 29.71, 29.41, 27.92, 27.83, 22.69, 14.11 ppm; FT-IR/ATR: 3333, 2922, 2852, 1738, 1668, 1528, 1441, 1317, 1211, 1150, 1053, 1016, 966, 802, 739, 686, 588, 554, 425 cm-1. MS (ESI-TOF) Calculated for C132H168O24N8Na[M+Na]+: m/z =2273.2096, Found: m/z =

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7,11,15,28-Tetrakis[((O-t-butyl-(O-t-butyl)L-serinyl)carbonyl)methoxy]-1,

21,

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25-

tetraundecyl cavitand(7g)

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O-t-Butyl-L-serine t-butyl hydrochloride (0.44 g, 1.75 mmol), was used as in the general method. White solid. (0.46 g, 59 %), Rf = 0.55 (3 % MeOH/CH3Cl), mp 60-63ºC; [α]20D =

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+60.48 (c = 1.00, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.23 (d, J = 8.6 Hz, 4 H, NH), 6.82 (s, 4 H, ArH), 6.09 (d, J = 7.1 Hz, 4 H, outer of OCH2O), 4.72 (q, J = 5.7 Hz, 4 H, Ser-αH), 4.72 (t,J = 8.0 Hz, 4 H, CH (methine)), 4.61 (d, J = 15.8 Hz, 4 H, ArOCH2), 4.52 (d, J = 7.1 Hz, 4 H, inner of OCH2O), 4.45 (d, J = 15.8 Hz, 4 H, ArOCH2), 3.84 (dd,J = 3.1 Hz, J= 3.1 Hz,4 H, Ser-β CH2), 3.54 (dd, J = 2.6 Hz, J = 2.52 Hz, 4 H, Ser-β CH2), 2.17 (q, J = 6.4 Hz, 8 H, CH2(CH2)9CH3), 1.48 (s, 36 H, Ser-t-But), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 1.15 (s, 36 H, Ser- t-But), 0.87 (t,J = 6.5 Hz, 12 H, CH3) ppm; 13C NMR [CDCl3, 100 MHz]: δ = 169.10, 168.95, 147.32, 146.99, 144.23, 139.14, 138.70, 114.57, 99.49, 81.81, 73.12, 72.95, 62.44, 53.22, 52.95, 36.91, 31.94, 29.87, 29.76, 29.72, 29.40, 28.05, 27.93, 27.32, 23.20, 22.68, 14.10 ppm; FT-IR/ATR: 3339, 2922, 2852, 1738, 1667, 1529, 1440, 1316, 1211, 1150, 1053, 1016, 966, 802, 738, 685, 588, 557, 425 cm-1. MS (ESI-TOF) Calculated for C128H204O28N4Na [M+Na]+: m/z = 2269.4587, Found: m/z = 2269.4587.

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7,11,15,28-Tetrakis[((O-methyl-(Oγ-methoxy)-L-gulamylacid)carbonyl)methoxy]-1, 21, 23, 25-tetraundecyl cavitand(7h) L-Glutamic

acid dimethyl ester hydrochloride (0.37 g, 1.75 mmol), was used as in the general

method. White solid. (0.42 g, 58 %), Rf = 0.42 (3 % MeOH/CH3Cl), mp 56-59ºC; [α]20D =

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+63.33 (c = 1.00, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.22 (d, J = 7.7 Hz, 4 H, NH), 6.87 (s, 4 H, ArH), 6.12 (d, J = 6.8 Hz, 4 H, outer of OCH2O), 4.72 (q, J = 8.56 Hz, 4 H, Glu-αH), 4.72 (t,J = 7.2 Hz, 4 H, CH (methine)), 4.59 (d, J = 5.0 Hz, 8 H, ArOCH2), 4.48 (d, J = 6.8 Hz, 4 H, inner of OCH2O), 3.80 (s, 12 H, OCH3), 3.61 (s, 12 H, OCH3), 2.30-2.50 (m, 8 H, Glu-

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γH), 1.90-2.20 (m, 4 H, Glu-βH), 2.19 (q,J = 5.1 Hz, 8 H, CH2(CH2)9CH3), 1.90-2.20 (m, 4 H, Glu-βH), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 0.89(t,J = 6.5 Hz, 12 H, CH3) ppm; 13C NMR

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[CDCl3, 100 MHz]: δ = 172.88, 172.03, 169.00, 147.02, 146.67, 143.95, 139.34,138.93, 114.82, 99.67, 72.94, 55.34, 52.62, 51.70, 51.02, 37.01, 31.93, 29.99, 29.76, 29.72, 29.41, 27.93, 27.71, 24.73, 22.69, 14.10 ppm; FT-IR/ATR: 3332, 2923, 2853, 1735, 1678, 1528, 1435, 1375, 1317, 1205, 1152, 1099, 1044, 1016, 967, 803, 686, 589, 501, 434 cm-1. MS (ESITOF) Calculated for C112H164O32N4Na[M+Na]+: m/z = 2101.1254, Found: m/z = 2101.1455.

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7,11,15,28-Tetrakis[((O-benzyl-Nεε-benzyloxyl-L-lysinyl)carbonyl)methoxy]-1,21,23,25tetraundecyl cavitand(7i)

N-ε-Cbz-L-lysine benzyl ester hydrochloride (0.71 g, 1.75 mmol), was used as in the general

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procedure. White solid. (0.65 g, 65 %), Rf = 0.45 (3 % MeOH/CH3Cl), mp 55-57ºC; [α]20D = +30.00 (c = 1.00, CHCl3); 1H NMR [CDCl3, 400 MHz]: δ = 8.07 (d, J = 8.0 Hz, 4 H, NH),

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7.23-7.43 (m, 40 H, Lys-ArH), 6.80 (s, 4 H, ArH), 6.00 (d, J = 7.0 Hz, 4 H, outer of OCH2O), 5.09 (d, J = 12.3 Hz, 8 H, Lys-cbz-CH2O), 4.99 (s, 8 H, Lys-Bn-CH2O), 4.71 (t,J = 7.2 Hz, 4 H, CH (methine)), 4.65-4.75 (m, 4 H, Lys-αH), 4.50 (d, J = 16.0 Hz, 8 H, ArOCH2), 4.39 (d, J = 7.0 Hz, 4 H, inner of OCH2O), 3.04 (q, J = 5.2 Hz, 8 H, Lys-ε CH2), 2.10 (q,J = 6.8 Hz, 8 H, CH2(CH2)9CH3), 1.75-1.85 (m, 4 H, Lys-β CH2), 1.85-1.90 (m, 4 H, Lys-β CH2), 1.30-1.40 (m, 8 H, Lys-δ CH2), 1.30-1.40 (m, 8 H, Lys- γ CH2), 1.20-1.28 (m, 72 H, CH2(CH2)9CH3), 0.83 (t,J = 6.7 Hz, 12 H, CH3) ppm, 13C NMR [CDCl3, 100 MHz]: δ = 172.07, 168.85, 156.33, 147.04, 146.73, 143.98, 139.32, 138.85, 136.62, 135.19, 128.68, 128.55, 128.48, 128.24, 128.04, 114.79, 99.69, 73.02, 67.21, 66.56, 51.49, 40.80, 37.08, 32.46, 31.94, 30.01, 29.82, 29.80, 29.77, 29.74, 29.42, 29.37, 28.04, 22.70, 22.32, 14.12 ppm; FT-IR/ATR: 3348, 3033, 2924, 2853, 1720, 1677, 1523, 1445, 1316, 1242, 1182, 1146, 1081, 1049, 1015, 966, 802,

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735, 696, 587, 456 cm-1. MS (ESI-TOF) Calculated for C168H216O32N8Na[M+Na]+: m/z = 2881.5445, Found: m/z = 2881.5395 References

6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31.

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Lehn, J. M., Ed. Supramolecular Chemistry Concepts and Perspective; VCH, Weinheim, 1995. Cram, D. J., Cram, J .M, Ed. Container Molecules and Their Guests, Monographs in Supramolecular Chemistry; RSC, 1994. Tunstad, L. M.; Tucker, J. A.; Dalcanale, E.; Weiser, J.; Bryant, J. A.; Sherman, J. C.; Helgeson, R. C.; Knobler, C. B.; Cram, D. J. J. Org. Chem.1989,54, 1305-1312. Vincenti, M.; Minero, C.; Pelizzetti, E.; Secchi, A.; Dalcanale, E. Pure Appl. Chem.1995,67, 1075-1084. Haino, T.; Rudkevich, D. M.; Shivanyuk, A.; Rissanen, K.; Rebek, J. Chem. Eur. J.2000,6, 3797-3805. Dalcanale, E.; Soncini, P.; Bacchilega, G.; Ugozzoli, F. J. Chem. Soc., Chem. Commun.1989, 500-502. Timmerman, P.; Verboom, W.; Reinhoudt, D. N. Tetrahedron1996,52, 2663-2704. Jasat, A.; Sherman, J. C. Chem. Rev.1999,99, 931-967. Botta, B.; Cassani, M.; D'Acquarica, I.; Subissati, D.; Zappia, G.; Delle Monache, G. Curr. Org. Chem.2005,9, 1167-1202. Boerrigter, H.; Verboom, W.; Reinhoudt, D. N. J. Org. Chem.1997,62, 7148-7155. Yoon, J.; Paek, K. Tetrahedron Lett.1998,39, 3161-3164. Hamada, F.; Ito, S.; Narita, M.; Nashirozawa, N. Tetrahedron Lett.1999,40, 1527-1530. Pellet-Rostaing, S.; Nicod, L.; Chitry, F.; Lemaire, M. Tetrahedron Lett.1999,40, 87938796. Paek, K.; Yoon, J.; Suh, Y. J. Chem. Soc., Perkin Trans. 22001, 916-922. Boerrigter, H.; Grave, L.; Nissink, J. W. M.; Chrisstoffels, L. A. J.; van der Maas, J. H.; Verboom, W.; de Jong, F.; Reinhoudt, D. N. J. Org. Chem.1998,63, 4174-4180. Dumazet, I.; Beer, P. D. Tetrahedron Lett.1999,40, 785-788. Lucking, U.; Rudkevich, D. M.; Rebek, J. Tetrahedron Lett.2000,41, 9547-9551. Ahn, D. R.; Kim, T. W.; Hong, J. I. Tetrahedron Lett.1999,40, 6045-6048. Tucci, F. C.; Rudkevich, D. M.; Rebek, J. J. Org. Chem.1999,64, 4555-4559. Gibb, B. C.; Mezo, A. R.; Causton, A. S.; Fraser, J. R.; Tsai, F. C. S.; Sherman, J. C. Tetrahedron1995,51, 8719-32. Mezo, A. R.; Sherman, J. C. J. Am. Chem. Soc.1999,121, 8983-8994. Berghaus, C.; Feigel, M. Eur. J. Org. Chem.2003, 3200-3208. Elidrisi, I.; Negin, S.; Bhatt, P. V.; Govender, T.; Kruger, H. G.; Gokel, G. W.; Maguire, G. E. M. OBC2011,9, 4498-4506. Higler, I.; Timmerman, P.; Verboom, W.; Reinhoudt, D. N. J. Org. Chem.1996,61, 5920-5931. Lee, S. B.; Hwang, S.; Chung, D. S.; Hong, J.-I. Tetrahedron Lett.1997,38, 8713-8716. Sansone, F.; Barboso, S.; Casnati, A.; Fabbi, M.; Pochini, A.; Ugozzoli, F.; Ungaro, R. Eur. J. Org. Chem.1998, 897-905. Frkanec, L.; Visnjevac, A.; Kojic-Prodic, B.; Zinic, M. Chem.-Eur. J.2000,6, 442-453. Ree, M.; Kim, J.-S.; Kim, J. J.; Kim, B. H.; Yoon, J.; Kim, H. Tetrahedron Lett.2003,44, 8211-8215. Batchelder, L. S., Sullivan, C.E, Jelinski, L.W, Torchia, D.A. Proc. Natl. Acad. Sci. U.S.A1982,79, 386-389. Iwanek, W. Tetrahedron-Asymmetry1998,9, 3171-3174. Bryant, J. A., Blanda, M.T, Vincenti, M, Cram, D.J. J. Am. Chem. Soc.1991,113, 2167-2172.

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Paek, K.; Joo, K.; Kwon, S.; Ihm, H.; Kim, Y. Bull. Korean Chem. Soc.1997,18, 80-86. Irwin, J. L.; Sherburn, M. S. J. Org. Chem.2000,65, 602-605. Timmerman, P.; Nierop, K. G. A.; Brinks, E. A.; Verboom, W.; van Veggel, F. C. J. M.; van Hoorn, W. P.; Reinhoudt, D. N. Chem.-Eur. J.1995,1, 132-43. Irwin, J. L.; Sherburn, M. S. J. Org. Chem.2000,65, 5846-5848.

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Supporting Information

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Synthesis and NMR Elucidation of Novel Amino Acid Cavitand Derivatives Iman Elidrisi,[a] Pralav V. Bhatt,[a] Thavendran Govender,[b] Hendrik G. Kruger,[a] and

a

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Glenn E. M. Maguire,[a]*

School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Private Bag

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X54001, Durban 4000 South Africa, b

School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000 South Africa

S3: COSY NMR spectrum of 7a-i S4: HSQC NMR spectrum of 7a-i S5: Infrared Spectrum 5,6 and 7a-i

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S2: 13C NMR spectrum of 5,6 and 7a-i

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*Email: [email protected]

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S1: 1H NMR spectrum of 5 in CDCl3 (400 MHz)

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13

C NMR shifts for compounds 7a-i 7d 7e 7f 143.8 143.92 143.37 139.40 138.86 138.94 114.8 114.38 114.59 146.67 147.56 146.87 37.01 36.90 36.79 72.87 72.14 72.45 168.79 167.04 168.87 99.62 99.99 99.08

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7h 143.95 138.93 114.82 147.02 37.01 72.94 169.0 99.76

7i 143.98 138.85 114.79 147.04 37.08 73.02 168.85 99.69

172.58 52.29 59.01 46.86 24.94 28.84 31.95,31.49,

172.52 109.59, 111.3 118.46,119.54, 122.8,127.62, 136.13,138.3 52.52 52.54 27.92 31.9,29.93,

169.1 81.8 52.95 53.22 62.44 23.2 31.94,29.87,

172.03,172.88 52.62, 51.7 51.02 29.99 29.41 31.93,29.76,

172.07, 156.33 136.62,135.19, 128.68,128.55, 66.56,67.21 128.48,128.24, 128.04 51.49 29.42 22.7 29.37 40.8 32.46,31.94,

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27.71,24.73,

29.77,29.74,

29.41,27.83,

27.32,22.68,

22.69,14.1

29.8,28.04,

22.69,14.11

14.11

TE D

AC C

29.41,27.92,

7g 144.23 138.7 114.57 147.32 36.91 72.95 168.95 99.49

173.22 52.30 50.26 31.75 24.84 22.85 14.03 31.92,29.96,

EP

Carbon 7a 7b 7c C1/C5 143.96 143.98 143.89 C2/C4 139.1 139.36 139.15 C3 114.85 114.83 114.7 C6 146.96 146.81 146.67 C7 36.98 36.91 36.93 C8 72.97 73.05 72.85 C9(C=O) 169.67 168.66 168.51 C10 99.66 99.64 99.3 AAC* (C=O) 169.33 173.24 170.12 Aromatic 126.97,128.40, t-BuO 129.32 -OCH2 61.64 -OCH2Ph -OCH3 52.52 52.34 Ot-Bu α-C 40.88 47.64 52.92 β-C 18.56 38.42 Υ-C δ-C ε-C -CH3 14.18 “Feet” 31.94,29.93, 31.94,29.86, 31.93,29.97, AAC* denotes amino acid carbon peaks 29.72,29.74, 29.74,29.72, 29.80,29.76,

RI PT

Table-1:

29.71,29.41,

27.94,22.97,

28.01,22.69,

22.67, 22.02,

14.11

14.09

14.11

22.32,14.11

ACCEPTED MANUSCRIPT

101.8

RI PT

95 90 85

SC

80

M AN U

75 70 65 60

TE D

55 50

EP

45 40 35

 

28.0 4000.0

3600

3200

AC C

%T

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 5

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

101.8 100

RI PT

95 90

SC

85

M AN U

80 75 70 65

TE D

60 55

EP

50 45

 

40 38.0 4000.0

AC C

%T

3600

3200

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 6

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

102.0 100

RI PT

95 90 85

SC

80

M AN U

75 70 %T 65 60

TE D

55 50

EP

45

35

 

30.0 4000.0

AC C

40

3600

3200

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7a

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

102.9 100

RI PT

95 90 85

SC

80

M AN U

75 70 65 60

TE D

55 50 45

35

 

30

23.0 4000.0

3600

3200

EP

40

AC C

%T

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7b

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

102.7 100

RI PT

95 90 85

SC

80

M AN U

75 70 65 60

TE D

55 50

40 35

 

30 27.0 4000.0

3600

3200

EP

45

AC C

%T

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7c

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

101.7

RI PT

95 90 85

SC

80

M AN U

75 70 65 60

TE D

55 50

EP

45 40 35

 

29.0 4000.0

3600

3200

AC C

%T

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7d

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

101.7

RI PT

95 90

SC

85 80

M AN U

75 70 %T 65 60

TE D

55 50

EP

45

35

 

30.0 4000.0

AC C

40

3600

3200

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7e

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

100.5

RI PT

95 90 85

SC

80

M AN U

75 70 %T 65

TE D

60 55 50

EP

45 40

4000.0

3600

3200

AC C

 

35 33.0

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7f

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

99.6

RI PT

95 90

SC

85 80

M AN U

75 70 65

TE D

60 55

EP

50 45

 

40 36.0 4000.0

3600

3200

AC C

%T

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7g

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

RI PT

101.7 100

95

SC

90

85

75

TE D

70

65

EP

60

55

 

50 48.0 4000.0

AC C

%T

M AN U

80

3600

3200

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7h

1200

1000

800

600

380.0

ACCEPTED MANUSCRIPT

101.3

RI PT

95 90

SC

85 80

M AN U

75 70 %T 65

TE D

60 55

EP

50

40

 

36.0 4000.0

AC C

45

3600

3200

2800

2400

2000

1800

1600

1400

cm-1

S5: Infrared spectrum of 7i

1200

1000

800

600

380.0