Structural and conformational study of azabicyclanones

411

Journal of Molecular Structure, 142 (1986) 411-415 Elsevier Science Publishers B.V., Amsterdam -Printed

STRUCTURAL

AND CONFORMATIONAL

in The Netherlands

STUDY OF AZABICYCLANONES.

E. GALVEZ? I. ARDID! L.FUENTESj F. FLORENCIO: S. GARCIA 1 Dpto. Qulmica Orgdnica. Univ. Alcald de Henares. 2 Inst. QuImica-Flsica. "Rocasolano". C.S.I.C. Madrid.

BLANCO?

ABSTRACT 3-Phenethyl-3-azabicyclo(3.2.l.)octan-8-one (I), 3-Phenethyl-3-azabicyclo (3.3.l)nonan-g-one (II), and 8-Phenethyl-8-azabicyclo(4.3.l)decan-lo-one (III) have been studied by k, uC NMR and IR spectroscopy and the crystal structure of compound II has been determined by X-ray diffraction. The ketones studied adopt. in CDCl solution a flattened chair conformation in the piperidine ring. This flattentng increases from I to III. This fact is due to the increasing steric ef feet exerted by the polimethylene chain. X-ray data for compound II have revealed that the compound II has crystallized in a flattened chair-chair conformation.

INTRODUCTION In a previous

paper

(ref.1) we reported

study of diazabicyclanones

and diazabicyclanols.

this paper the structural.and conformational

sis of I-III

(ref. 2)

cycloalkanone clanone

Scheme

the structural

is shown in Scheme

with formaldehyde

and

and conformational

In the same line,

study of compounds

1. From the reaction

a-phenethylamine,

I-III.

we report in The synthe

of the suitable

the corresponding

azabicy

is obtained.

1

+

HCHO

+

PhCH2CH2NH2

n= 2, I n= 3, II n= 4, III EXPERIMENTAL IR spectra were recorded were compressed a Bruker_WM360 Varian

on a Perkin Elmer 599 spectrophotometer. All canpeunds 1 H NMR spectra were obtained at 360 MHz with 13 spectrometer. C NMR spectra were determined at 20 MHz with the into KBr

pellets.

FT 80 in the Fourier transform

CDC13 using TMS as internal

0022-2S60/36/$03.50

mode. All

of the spectra were obtained

reference.

0 1986 Elsevier Science Publishers B.V.

in

412 A prismatic crystal of 0.10 x 0.15 x 0.30 mm was used to determine the cell parameters in a Philips PN 1100 four circle diffractometer.Lattice parameters were refined by a least-squaresfit of 25 reflections. Intensity data were collected from the same crystal in the same diffractometer with graphite-monochromatedCut& radiation for 2te<65 h2a

, Max hkl 12 15 14. The

scan technique was used. Of the 2422 reflections measured, 1670 was consid o being determined from counting statistics.

ered as observed with I >20 (I), The crystal data are given

in Table 1.

RESULTS AND DISCUSSION Description and discussion of the structure Figure 1 shows a view of the molecule and the numberings for the crystallographic study. Bond lengths, valence and torsion angles are given

in Table 2.

TABLE 1 Crystal dataa :'%27(l)A = Ii 451(1)A ,b= 11:939(1)A s= 103.13(1)Q Space group

C16H21No

P21lc

aStandard deviations, given

V = 1422.6(8) i3 2=4 -3 D = l.l36(2)Mg m F'(OO0) = 528 !J=5.115 hMoKa = 1.5418

in parentheses, refer to the least significant

digits.

Fig. 1 Perspective view and numbering of compound II.

413 TABLE 2 Bond distances

( h )

Cl -c2 Cl - c9 N3 - c4

Cl - C8 C2 - N3 N3 - Cl1

l-522(6) 1.490(5) 1.452(5)

;; : ;;

;;

C7 - C8 Cl1 - Cl2 Cl3 - Cl4 Cl4 - Cl5 Cl6 - Cl7

::2--'::3 Cl3 - Cl8 Cl5 - Cl6 Cl7 - Cl8

1.381(6)

c2 - Cl - c9

107-l(3)

1.352(7)

Bond angles

C8 - Cl ;; : ;; C4 - N3 - c5 :: - c5 C6 - C7 ;; I ;; Cl1 - Cl2 Cl2 - Cl3 Cl3 - Cl4 Cl5 - Cl6 Cl3 - Cl8

(')

C9 C8 Cl1 Cl1 c9 c9 C8 c5 010 - Cl3 - Cl4 - Cl5 - Cl7 - Cl7

;: : ;; : ;; N3 C4 C5 Cl c5

-

c4 C5 C6 C8 c9

c5 C6 C7 C7 010 - Cl2 !:2--?;3 - Cl8 Cl4 - Cl3 - Cl8 Cl4 - Cl5 - Cl6 Cl6 - Cl7 - Cl8

112.4(4)

The N3 . ..C7 distance (2.62 1

: ;;

(2.905(5) A

) (ref. 3) between the 3 and 7 positions.

0.715(4)

8, so that the piperidine In the cyclohexane

square plane through the cyclohexane phenethyl

the molecules

The displacements

ring adopts a slightly

ring, the displacements

ring adopts also a slightly the equatorial

in the crystal

takes place through

and

chair confor-

of C7 and C9 from the least and 0.710(4)

flattened

position.

flattened

distance

of N3 and

Cl, C2, C4, C5, are -O-633(3)

Cl, C5, C6, C8 are -O-543(5)

group occupies

125.2(3) 113.1(3) 120.6(4) 116.9(3) 120.3(4) 120.0(4)

) is largest than the theoretical

C9 from the least square plane through

mation.

-

A

consequently,

chair conformation.

In compound

The

II the packing of

Van der Waals forces.

JR spectra According bands

to the crystal

in the infrared

the axially

oriented

compound

(2850-2600

C - H bonds

(ref. l).The spectroscopy compound

structure,

spectra

in a positions

behavioyr

of compounds

II in the 2850-2600 cm region. -1 1760, 1740, 1730 cm respectively.

II show characteristic

Bohlmann

cm-'). These bands are originated

The

in relation I and III

by

to the nitrogen atuns

are similar to that of

u(C=O) bands of I-III are at

chemical

61.82

45.35

48.75 47.95

I

ka

20.91

C 7

I-III

for compound

reasons, the numbering

aFor homogeneity

34.79

C 6(8)

at 20 MHz. Solvent CDC13.

22.65

C 6(7)

Spectra recorded

59.80 60.42

C 2(4)

C l(5)

(ppm) for compounds

Compound

shifts

chemical

Carbon-13

TABLE 4

H 6(Veq 1.9 m

1.8 m

H Wax

C 6(9)

III

26.54

C 7(8)

is altered.

31.94

1.38 dtt

H 7eq

‘J 13 ‘J 3

2m

H 7ax

CHP

217.94 213.29 58.71 59.20

219.64 57.1

C=O

1.30 m

33.99 33.95

34.0

CH26

2.8 t 3J 7.5

7.81-t )J 7.5

<;7; ;

CH2a

128.61 128.57

128.60

ortho

7.15-7.3

7.18-7.32m

para

C-ipso

t, triplet

2.61 t U 7.7

2.56 t

128.28 125.98 128.29 125.96 140.37 140.25

m

7.18-7.30m

Ph

128.26 125.96 140.34

meta

CH26 2.70 t

m, multiplet;

H 7Weq

1.79 m

H 7(8jax

of doublets;

1.79 m

H 6(9jeq

1.54 m

H 6(9)ax

br, broad; dd, doublet

2.11 dd

H 6Weq

2.0 m ‘J 13.29 ‘J 2.2

H 6(8J,,

(J, Hz) for compounds I-ITT

CDC13. Abbreviations:

2.87 d ‘J 11.31

3t.23 d J 10.88

3.03 d

Solvent

2.43 dd ‘J 11.62 ‘J 2.4

at 360 MHz.

WI/2 17

2.59 brs

Spectra recorded

:IIa

I

111a

II

dd ;J 10 52

2.6

WI/2 10 2.35 brs

WI/2 9

2.56 dd

2.15 brs

I

H 2(41eq

( 6, ppm) and multiplicities

H 2(41ax

shifts

H l(5)

Compound

'H NMR

TABLE 3

415 NMR Spectra The 'H and l3C NMR data of I-III are summarized in Tables 3 and 4 respectively. 13 From the 'H and C NMR data of I-III, the following general features were deduced:

(a) In CDC13 solution

formation; exerted

(b) This flattening

by the polimethylene

atom adopts

an equatorial

The above statements compounds electron

attributed coplanar

to

In compound

pounds

are substantiated signals

o-electron

attached

as follows.

correspond

to the nitrogen

delocalization

In the 'H NMR spectra

of

to protons gauche to the nitrogen

appears

at higher field which

of the nitrogen

is

lone pair in trans-

In II and III, J H2 4 ax is greater than J H2 4 eq;co"sequefltlY

,

angle H2,4 eq- C - C - H,_5 is greater II theAsH

effect exerted

chair con-

from I to III due to the steric effect

(c) the radical

(ref. 1); H 2(4) ax signals

C-H bonds.

the dihedraL

increases

chain;

ring adopts a flattened

position.

I-III, H 2(4)eq pairs

the piperidine

than H2,4 ax- 'C - C - H, 5.

(7)ax -6H (7),; 0.6 ppm is attributed

by the nitrogen

to the deshieldini

lone pair (ref. 1). It is also observed

in com-

I and III.

The sequence increased

SC (2,4) (I)>sC (2,4) (II)> SC (2,4) (III) is consistent

eclipsing

flattening

between

the H 2(4)ax-

from I to III in the piperidine

The N-CH2- aI3 C chemical equatorial

position

H l(5) as a consequence

to the

of the increased

ring.

shifts are consistent

with a phenethyl

group

in an

(ref. 1).

CONCLUSIONS From X-ray diffraction, concluded mational

IR, 'H and l3C data of compounds

that these compounds

occupy

space in both solutions

approximately

and the crystalline

I-III it can be

the same region of conforstate.

ACKNOWLEDGEMENTS We thank the Comisi6n for partial

Asesora

de Investigacidn

Cientifica

y Tecnica

(Grant1750)

support of this research.

REFERENCES

1 E. Galvez, M.S. Arias, J. Bellanato, J.V. Garcia-Ramos, Verdier, S. Garcia-Blanco, J. Mol. Str., 127 (1985) 185. 2 I. Ardid, unpublished results. 3 N. C. Webb, M. R. Becker, J. Chem. Sot. B (1976) 1317.

F. Florencio,

P. Smith