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1H- and 13C-nuclear magnetic resonance study of reducing disaccharides of d -xylopyranose
Carbohydrufe Research, 98 (1981) l-9 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands
‘H- AND 13C-NUCLEAR MAGNETIC RESONANCE DISACCHARIDES OF D-XYLOPYRANOSE JEAN-PIERREUTILLE AND
STUDY
OF REDUCING
PHILIPPEJ. A. VIXTERO
Centre de Recherches sur les Macrontoltkules
V&g&ales, C.N.R.S. *, 53 X, 3804I Grenoble (France)
(Received December lOth, 1980; accepted for publication in revised form, June llth,
1981)
ABSTRACT
‘H- and ‘3C-n.m.r. data for the six hexa-0-acetyl, reducing disaccharides composed of D-xylopyranose units are reported_ The chemical shifts were compared with those of some of the penta-0-acetyl or penta-0-acetyl-mono-0-chloroacetyl derivatives. The effects observed on the chemical shifts due to the absence of one 0-acetyl group from the hexa-0-acetyl D-xylobioses are discussed, as well as the effects of the substitution of one 0-acetyl by one 0-chloroacetyl group on the protons of carbon atoms in a close vicinity to the substituted sites. INTRODUCTION Ten D-xylopyranose, reducing disaccharides have been synthesized’, according to the Helferich and Zimer method’, by condensation of 2,3,4-tri-0-acetyl-3, 2+di0-acetyl-3-0-chloroacetyl-‘, and 2,3-di-O-acetyl4O-chloroacetyl-a-D-xylopyranosyl bromide4 with tri-0-acetyl-P-D-xylopyranose derivative?, in the same manner as previously reported 6 for the preparation of the per-0-acetyl derivatives of 4-O-aand -/I-D-xylopyranosyl-@%xylopyranose. Mixtures of the two possible glycoside anomers were separated by silica gel column chromatography; have been prepared’
from
compounds
7 and 12
6 and 11,respectively. This report describes the ‘H-n.m.r.
data of l-7, 9, 11, and 12 for spectra recorded at 250 MHz, of l-12 for spectra recorded at 62.86 MHz.
and the 13C-n.m.r. data
REsUr.Js AND DIsCUSSION ‘H-N.m.r. The ‘H-n.m.r. spectra of 1-7, 9, 11, and 12 (Tables I and II) could be interpreted, in general, by a first-order analysis. The signals for H-4, -5a, and -5b on one hand, and for H-4’, -5’a, and -5’b on the other hand formed ABX spin systems. In order to refine the results of the analysis, experimental spectra were simulated. Successive homo-indor or double irradiation experiments, starting from H-l
or -1’ allowed an unequivocal
*Laboratoire
propre du C.N.R.S.,
ass&6
assignment for ali of the remaining ring-protons. ti I’Universite Scientifique et Medicale de Grenoble.
0008-6215/81/ ooo(Mooo/%02.75,@ 1981-
Elsevler ScientificPublishing Company
2
_ J.-P.
uTILLE,
P. J. A. VOTTERO
*co++_*coeyAc OAc
3R
=
4 R =
AC
SR
=
AC
ClCH&O
6R
=
UCH$O
7R
=
ii
OAc
OAc
8R
=
AC
10R
=
At
SR
=
CICH2C0
11 R
=
CiCH$O
12R
=
H
The spectra of the per-O-acetylated compounds were compared with those of derivatives bearing, in the nonreducing unit, a chloroacetyl or a free hydroxyl group at the same position as that of the glycoside linkage in the reducing unit. In ‘3C-n.m.r. spectroscopy, substitution of an acetyl by a chloroacetyl group results in a downfield shift of the signal of the corresponding, substituted ring carbonatom and in a slight upfield shift of the signals of the two neighboring carbon atoms (see section on 13C-n.m.r. results). In ‘H-n.m.r. spectroscopy, substitution by a chloroacetyl group did not bring any important and characteristic modification of the lH chemical-shifts, and only slight downfield shifts (Ada ~0.8) were displayed- by the signals of the protons in close proximity to the substituent group. However, the removal of one acetyl group in 5 and 10 to give 7 and 12, respectively, resulted in a great upfield shift of the signal for the free hydroxyl geminal proton (cceffect: 6 - 1.11 and -1.37) without significant changes in the other region of the spectrum (B e&ct: 6 -0.10 to -0.20).
(8-D-(143)]
[a-D-(1+2)] [@-D-(1 32)] [N-D-(1+3)]
H-2 (dd,’
3.67 3.16 5.02 5.01 4.96 4096 4.96 4.93 4.98 4.98
H-I
(d)”
5.52 5.73 5,79 5,79 5,70 5,72 5.72 5.68 5.66 5.66
(rn)
4.81 4.92 4.87 4.87 4.97 4.98 4.96 3.90 3.90 3.88
5.13 5.20 3.97 3.96 3.89 3.90 3.89 5.21 5.17 5.17
H-4
(t)
H-3
3.93 4.08 4.18 4.18 4.13 4.13 4.14 4.07 4.04 4.03
(dd)
H-5ad
3.38 3052 3.53 3.53 3.53 3.53 3.53 3.62 3.49 3.48
(dd)
H-Sbd
5.20 4.69 5.30 5.29 4.65 4,69 4.65 5.22 4.62 4.56
(d)
H-l’
4.58 4.85 4.78 4.82 4086 4,90 4.74 4.72 4.82 4.80
(dd)
H-2’
5.21 5.10 5.40 5.46 5.10 5.16 3.73 5.42 5.11 4.90
(1)
H-3’
4.83 4.91 4.98 5.01 4.92 4.96 4.81 5.01 4.97 3.79
(I??)
H-4’
3.64 4.14 3.81 3.82 4.13 4.15 4.11 3.85 4.14 4.02
H-5’& (dd)
3.48(t) 3.42(dd) 3.69(t) 3.70(l) 3.4l(dd) 3.43(dd) 3.39(dd) 3.63(t) 3.48(dd) 3.39(dd)
H-5’bd (I ordd)
1.87-2.03 2.00-2.10 2.00-2.16 2.00-2.16 2.04-2.17 2.04-2.16 2.05-2.11 2.04-2.08 2.07-2.11 2.04-2.12
?
4.01 4.08
4.02
3.97
CH2Cl (s)
aFrom the signal of an internal standard of Me&i for solutions in chloroform-d. *lH-n.m.r. data for 8 and 10 are given in ref. 6. CMultiplicity in parentheses. dThesignals for&5band H-5’b are comparatively and respectively at a higher field than those for H-5a and H-5/a. CJH-n,m,r. spectra are given in ref. 8.
T [a-D-(134)] 11” [B-D-(1+4)] 12s
6”
1 2 3 46 5
cotnpo fofd
JH-CHEMICAL SHIFTS”(S) OFD-XYLODJOSES l-7, 9,11, AND 12”
TABLE I
w
1 2 3 4 5 6 7 9 11 12
* 7.25 6.75 5.50 5.40 6.00 6.00 5.50 7.00 7.00 7,25
Jr,2
9.00 8.25 6.50 6.50 7.25 7.25 7.00 8.25 8.50 8.50
Ja,s
9.00 8.25 6,50 6.50 7,25 7.25 6,65 8.25 8050 8.60
534
5.37 5.00 4.00 4.00 4.50 4.50 4.00 5.00
J1,KO
9.30 8.50 6.50 6.50 7.00 7.00 6.50 9.00 9.50 8.85
12.00 11.75 12.50 12.50 12.00 12.00 12.50 12.00 12.00 11.80
Jrin,sb
11, AND 12
J4,sb
1H-N.M,R.COLPLIWO-CONSTANTS (Hz) OFD-XYLODIOSES l-7,9,
TABLE II
3.75 6.00 3.75 3.75 6.25 6825 6.00 3.75 6000 6,OO --_-
J1#,21
10,Oo 7.75 10.00 10.00 7.75 7.75 7,55 WJO 7.50 8.00
J2',3'
-
5,47 4.50 600 6,OO 4,5O 450 4,60 6,OO 4.50 4,70
9.75 7.75 IO,00 10.00 7.75 7.75 7.30 10,OO 7,5O 7.85 -
JS’,ti’l7
J3',4'
11.50 7.50 11.00 11.00 7.75 7.75 7.20 11,Oo 3.00 8.25
Jd,db
---
11.06 12.00 11.00 11.00 12.00 12,oo 12,OO 11.00 12.00 11.80
h’n,5’b
ro’ I ?
“2
H
.” $ g
P
N.M.R.
OF D-XYLOBIOSES
Fig. 1. lH-N.m.r. xylopyranose (1).
spectrum of
1,3,~tri-O-aCetyl-2-0-(2,3,4-tri-0-acety~-~-D-X~~O~~~OS~~)-~-D-
I
I
5.73
Fig. 2. lH-N.m.r. xyloPyrano= (2).
3.42
spectrum of
5.79
Fig. 3. lH-N.m.r. xyloPyrano= (3).
1,3,4-~-0-acetyl-2-O-(2,3,dtri-O-acetyl-~-~xylop~osyl)-~-D-
353
spectrum of
P.P
1,2,Q-tri-O-acetyl-3-O-(2,3,4-tri-O-acetyl-~-~-~lop~nosyl)-~-~
Comparison of the spectra of the six hexa-0-acetyl disaccharides showed a good similarity between the chemical shifts of the protons belonging to nonreducing residues for disaccharides having a 8-D linkage (slightly perturbed, neighbouring giycoside linkage), whereas for compounds having an a-~ linkage differences of 6 0. E-O.20 were observed. It is known that, for a-o-linked disaccharides, the rotational angle 4 around the C-l’-0 bond of the glycoside linkage may be less restricted than that of the /3-D-linked disaccharides, which allows a wider environment_ The differences
pp.1
6
J.-P.UTILLE, P. J. A. VOTTERO
1
5'b
AA
6
5.70
3.41
Fig. 4. lH-N_m.r_ spectrum of xylopyranose (5).
P-P.1
1,2,~tri-O-acetyl-3-O-(2,3,etri-O-acetyl-~-~-xylop~nosyl)-~-~-
reported herein for the proton chemical shifts of the nonreducing unit of a-D-xylobioses may suggest an “exe-anomeric effect”‘. the position of the H-x signal relative For each glycoside linkage (C-l ‘+0-x), to those of H-5 and -5’ is characteristic of the glycoside linkage; for the B-D configuration, the H-x signal is located between those of H-5’a and -5a, and H-5b and -5’b; for the a-D configuration, it is located between that of H-5a and those of the group H-5’a, ..5b, and -5’b. The proton H-5’b exhibited a signal similar to a triplet ( J4ew5sb,N J Sna,Srb)for the a-D, and a doublet of doublets for the /I-D configuration. The chemical shifts of H-l’ or H-x, or of both, are not very characteristic of the nature of the (C-I’-sO-x) linkage, when compared to those observed in ‘3C-n.m.r. spectroscopy. 13C-N.m.r. - The signals of the carbon atcms were assigned by a Aective, heteronuclear-decoupling technique on the basis of ‘H-n.m.r. data (Table III). By TABLE III ‘3c-CHEhXAL
SHIFI-S (6)”
OF REDUCING
XYLOBIOSES
1-12
conlpoluld
C-l
c-2
c-3
c-4
c-5
1 2 3 4 5 6 7 8b 9 1W 11 12
93.84
92.80 91.81 91.98 92.07 92.05 92.22 92.00 91.95 92.41 92.22 92.34
74.38 76.61 69.45 69.72 70.13 70.03 7Q.40 70.15 70.03 70.13 70.01= 70.01
72.34 72.77 73.70 74.08 76.90 77.22 76.71 73.21 73.11 72.19 72.02 72.17
68.98 68.65 69.01 69.23 68.62 68.60 68.87 72.97 73.02 74.33 74.25 74.W
63.06 62.97 61.61 61.73 62.36 62.36 62.41 64.30 64.21 63.50 63.33 63.45
C-l' 95.40 100.86 96.00 96.15 101.03 101.Ol 101.18 96.51 96.4499.74 99-43 100.06
c-2’
c-3’
c-4
c-s
71.07 70.13 71.05 70.91 70.25 70.18 72.70 70.86 70.69 70.66 70.10= 70.61
69.13 70.68 69.21 71.41 70.81 72.73 71.22 69.08 68.82 70.78 69.91 74.47~
68.98 68.77 69.01 68.84 68.62 68.36 71.51 69.01 70.57 68.57 69.91 67.97
58.74 61.73 59.03 59.08 61.83 61.78 61.78 58.82 57.48 61.83 61.15 64.76
“From the siml of an internalstandardof Me&i for soIutions in chloroform-d; Spectra are given in ref. 8. bSeeref. 6. CChemicaEshift values of C-2 and -2’ for 11, and C-4 and -3’ for 12 may be transposed.
-0.27
to.12
-0.15
5 G-D) 10 V-D)
to.07
3’-OAc 4’-
9 @f-D) 11 (8-D) -0.05
to.05
-0.25 -0.22
-0.08
-0.09 -0.17
to.12
C-5
to.05
- 0.02
to.22
c-4
-0.15 -0.32
-0.02 -0.07 -0,31
to.15
C-l’
to.os
-2.93 to.60
-0.41 -3.69
-2.45 -1-0.05
-0.68
-0.05 -0.34
t 0.05
C-5’
-2.89
-1-2.20 -0.17 i-1.92 -0.26 -0.26 $1.56 -0.87 $1.34
-0.14 -0.07 -0.17 -0.56
C-4’
C-3’
C-2’
aDifferencebetweenthe shift position of a particularcarbon atom in any O-chloroacctyl-o-xylobiose derivativeand the resonanceof the equivalentcarbon atom in the parent hexa-O-acetyl-D-xylobiose. “Differencebetweenthe shift position of a particular carbon atom in hexa-CSacetyl-o-xylobioses 5 and 10 and the resonance ofthe equivalent carbon atom in the respectiveparent penta-0-acetyl-D.xylobioses 7 and 12.
to.02
i-o.19
i-O.32 -0.10 -0.17
$0.38
1-0.27 -0.10 -0.12 -0,12
-0.02 -0.05 -0.19
to.17
3’.OCOCHzCl 3’4’4’-
4(&D)
6 @D)
c-3
c-2
C-l
Compound
SubstitNent
CHEMICALSHlFTS(d)INDUCED ~YSUBSTITUTIONWITHCHLOROAC@TYLaORACETYLbOROUPS
TABLEIV
8
J.-P.
UTILLE,
P. J. A.
VOTTERO
use of 62.86-MHz spectroscopy, it was possible to assign almost all the peaks, some tentative interpretations being cotirmed on the basis of ester-group effects. It is well known that substitution of an acetyl group by a more electronegative group, such as the trichloroacetyl groupg, produces a general deshielding effect on the corresponding ring carbon-atom, and a shielding effect on the two neighboring ring carbon-atoms, as was observed for an octa-O-acetylgentiobiose derivative”. Esterification by a chloroacetyl group showed, in smaller magnitudes, an a effect in the range of 6 + 1.3-2.2 and a slight p effect of less than S -0.7 (Table IV). The influence of the substituent located in the nonredilcing residue takes place through bonding electrons rather than space, as no modification of the chemical shifts for the carbon atoms of the reducing part of the disaccharide was observed. On the other hand, comparison (Table IV) of the chemical shifts of carbon atoms of hexa-O-acetyl disaccharides with those of homologous penta-O-acetyl derivatives (free hydroxyl group in the nonreducing unit of 7 and 10) corroborates the effects that have been observed for O-acetyl groups in the D-xylopyranose series” and for L-rhamnose acetatesi’. The availability of all these reducing disaccharides allowed a comparison between the chemical shifts of the signals of C-l ’ atoms, the glycoside configuration, and the nature of the linkage C-1’-O-C-x (Table V). Each C-l and -1’ showed a specific shift relative to the glycoside linkage, with a set of values for the a-D configuration between 6 95.40 and 96.51 and for the B-D configuration between 6 99.74 and 101.03. However, it should be made clear that signals for C-l ’ atoms involved in the /3-D-(l’j2) and p-D-(1’-+3) linkages (2 and 5) are separated by not more than 6 0.17. Nevertheless, taking into account the general pattern of the C-l ’ signals, these signals TABLE
V
13c-CHEhlICAL
SHIFTS
OF c-1’
FOR
A c-l’-o-c-X
LIN?ZAGEO
_
c0nIp011nd
Linkpge
C-Pa
1 2
(1’+2)
95.40
3 4 5 6 7
(1’+3)
8 9
(1’+4j
C-I’~
C-X
100.86
74.38 76.61
101.03 101.Ol 101.18
73.70 74.08 76.90 77.22 76.71
96.00 96.15
96,51 96.44
10 11 12
“For 1-2, x = 2; for 3-7, x = 3; for S-12,x = 4.
99.74 99.43 100.06
72.97 73.02 74.33
74.25 74.55
N.M.R.
OF D-XYLOBIOSES
9
may he used to identify the nature of the glycoside linkages in oligo- or poly-D-xylose structures as per-0-acetyl derivatives. As co&d be expected, substitution at O-2, -3, and -4 of the reducing unit by a D-xylopyranosyl residue resulted in a great downfield shift of the corresponding signal (see Table V). These signaIs, which are generally more difficult to observe than those of the C-l atoms in analysis of mixtures of oligosaccharides or polysaccharides of complex structures, may ,however, bring complementary information and ronsrmation of the assignments. EXPJ3UMENTAL
The ‘H- and ‘3C-n.m.r. spectra were recorded with a Kameca apparatus at the Centre Grenoblois de Resonance Magnetique (France). The disaccharides were examined in solution in chioroform-d at 20”. Chemical shifts were measured relative to the signal of tetramethylsilane, used as internal reference_ For ‘H-n.m.r. spectroscopy, attribution of the signals was made by selective irradiation or Indor experiments; the chemical shifts and coupling constants were measured on a 600-Hz scale-width for spectra recorded at 250 MHz with tubes of 5-mm o.d. Proton-decoupled, 13C-n.m.r. spectra were obtained at 62.86 MHz with tubes of 8-mm o.d. by Fourier-transform experiments (16 k memory; pulse width, 13 ps, z-90”; acquisition time, 0.6; spectral windows, -200 p_p_m.; and enlargement, c-50 p.p_m.). Attribution of 13C signals was made by selective, heteronucleardecoupling experiments. General methods. -
ACKNOWLEDGMENTS
The authors thank Prof. D. Y. Gagnaire for helpful discussions, and the Centre Grenoblois de Resonance Magnetique for recording the ‘H- and ‘3C-n.m.r. spectra. REFERENCES 1 2 3 4
G. E~COFRER AND J.-P. Urru~, unpublished results. B. HELFERICH AND J. ZIRNER, Chem. Ber., 95 (1962)26042611. C. S. HUDSON AND J_ M. JOHNSON, J. Am. Chem. Sot., 37 (1915)2748-2752. J.-P. UTILLE ANDP. J. A. VO’ITERO, Curbohydr_ Res., 52 (1976) 241-245. 5 J.-P. UTILLE AND D. Y. GAGNAIRE, Carbohydr. Res., unpublished results. 6 J.-P. UTILLE ANDP. J. A. Vomo, Carbohydr_ Res., 53 (1977)259-262. Curbohydr_ Res., 65 (1978) 114-120. 7 S.P&EZANDR.H.MAR cHEssAUL.T, 8 J.-P. UTILLE, PGparation par synth& chimique ou par hydrolye aci’de de xy/ane.s, des oligom&es
de la s&ie du D-xylose. &de de ces composks et des polysaccharides correspondants par r.m.n, du proton et du carbone, TJ&e d’lht, Universitede Grenoble(France),1979. 9 M. R. VIGNON ANDP. J. A. Vomo, Tetruhedron I.&t., (1976) 2445-2448. 10 M.R. VIGNONAND P. J. A.V -0, Carbohydr_ Res., 53 (1977) 197-207. 11 J.-P. UW ANDP. J. A. Vomo, Curbohydr_ Res., 85 (1980) 289-297. 12 V. POZSGAY AND A. Neswrf~q Carbohydr. Res., 80 (1980) 196-202.
‘H- AND 13C-NUCLEAR MAGNETIC RESONANCE DISACCHARIDES OF D-XYLOPYRANOSE JEAN-PIERREUTILLE AND
STUDY
OF REDUCING
PHILIPPEJ. A. VIXTERO
Centre de Recherches sur les Macrontoltkules
V&g&ales, C.N.R.S. *, 53 X, 3804I Grenoble (France)
(Received December lOth, 1980; accepted for publication in revised form, June llth,
1981)
ABSTRACT
‘H- and ‘3C-n.m.r. data for the six hexa-0-acetyl, reducing disaccharides composed of D-xylopyranose units are reported_ The chemical shifts were compared with those of some of the penta-0-acetyl or penta-0-acetyl-mono-0-chloroacetyl derivatives. The effects observed on the chemical shifts due to the absence of one 0-acetyl group from the hexa-0-acetyl D-xylobioses are discussed, as well as the effects of the substitution of one 0-acetyl by one 0-chloroacetyl group on the protons of carbon atoms in a close vicinity to the substituted sites. INTRODUCTION Ten D-xylopyranose, reducing disaccharides have been synthesized’, according to the Helferich and Zimer method’, by condensation of 2,3,4-tri-0-acetyl-3, 2+di0-acetyl-3-0-chloroacetyl-‘, and 2,3-di-O-acetyl4O-chloroacetyl-a-D-xylopyranosyl bromide4 with tri-0-acetyl-P-D-xylopyranose derivative?, in the same manner as previously reported 6 for the preparation of the per-0-acetyl derivatives of 4-O-aand -/I-D-xylopyranosyl-@%xylopyranose. Mixtures of the two possible glycoside anomers were separated by silica gel column chromatography; have been prepared’
from
compounds
7 and 12
6 and 11,respectively. This report describes the ‘H-n.m.r.
data of l-7, 9, 11, and 12 for spectra recorded at 250 MHz, of l-12 for spectra recorded at 62.86 MHz.
and the 13C-n.m.r. data
REsUr.Js AND DIsCUSSION ‘H-N.m.r. The ‘H-n.m.r. spectra of 1-7, 9, 11, and 12 (Tables I and II) could be interpreted, in general, by a first-order analysis. The signals for H-4, -5a, and -5b on one hand, and for H-4’, -5’a, and -5’b on the other hand formed ABX spin systems. In order to refine the results of the analysis, experimental spectra were simulated. Successive homo-indor or double irradiation experiments, starting from H-l
or -1’ allowed an unequivocal
*Laboratoire
propre du C.N.R.S.,
ass&6
assignment for ali of the remaining ring-protons. ti I’Universite Scientifique et Medicale de Grenoble.
0008-6215/81/ ooo(Mooo/%02.75,@ 1981-
Elsevler ScientificPublishing Company
2
_ J.-P.
uTILLE,
P. J. A. VOTTERO
*co++_*coeyAc OAc
3R
=
4 R =
AC
SR
=
AC
ClCH&O
6R
=
UCH$O
7R
=
ii
OAc
OAc
8R
=
AC
10R
=
At
SR
=
CICH2C0
11 R
=
CiCH$O
12R
=
H
The spectra of the per-O-acetylated compounds were compared with those of derivatives bearing, in the nonreducing unit, a chloroacetyl or a free hydroxyl group at the same position as that of the glycoside linkage in the reducing unit. In ‘3C-n.m.r. spectroscopy, substitution of an acetyl by a chloroacetyl group results in a downfield shift of the signal of the corresponding, substituted ring carbonatom and in a slight upfield shift of the signals of the two neighboring carbon atoms (see section on 13C-n.m.r. results). In ‘H-n.m.r. spectroscopy, substitution by a chloroacetyl group did not bring any important and characteristic modification of the lH chemical-shifts, and only slight downfield shifts (Ada ~0.8) were displayed- by the signals of the protons in close proximity to the substituent group. However, the removal of one acetyl group in 5 and 10 to give 7 and 12, respectively, resulted in a great upfield shift of the signal for the free hydroxyl geminal proton (cceffect: 6 - 1.11 and -1.37) without significant changes in the other region of the spectrum (B e&ct: 6 -0.10 to -0.20).
(8-D-(143)]
[a-D-(1+2)] [@-D-(1 32)] [N-D-(1+3)]
H-2 (dd,’
3.67 3.16 5.02 5.01 4.96 4096 4.96 4.93 4.98 4.98
H-I
(d)”
5.52 5.73 5,79 5,79 5,70 5,72 5.72 5.68 5.66 5.66
(rn)
4.81 4.92 4.87 4.87 4.97 4.98 4.96 3.90 3.90 3.88
5.13 5.20 3.97 3.96 3.89 3.90 3.89 5.21 5.17 5.17
H-4
(t)
H-3
3.93 4.08 4.18 4.18 4.13 4.13 4.14 4.07 4.04 4.03
(dd)
H-5ad
3.38 3052 3.53 3.53 3.53 3.53 3.53 3.62 3.49 3.48
(dd)
H-Sbd
5.20 4.69 5.30 5.29 4.65 4,69 4.65 5.22 4.62 4.56
(d)
H-l’
4.58 4.85 4.78 4.82 4086 4,90 4.74 4.72 4.82 4.80
(dd)
H-2’
5.21 5.10 5.40 5.46 5.10 5.16 3.73 5.42 5.11 4.90
(1)
H-3’
4.83 4.91 4.98 5.01 4.92 4.96 4.81 5.01 4.97 3.79
(I??)
H-4’
3.64 4.14 3.81 3.82 4.13 4.15 4.11 3.85 4.14 4.02
H-5’& (dd)
3.48(t) 3.42(dd) 3.69(t) 3.70(l) 3.4l(dd) 3.43(dd) 3.39(dd) 3.63(t) 3.48(dd) 3.39(dd)
H-5’bd (I ordd)
1.87-2.03 2.00-2.10 2.00-2.16 2.00-2.16 2.04-2.17 2.04-2.16 2.05-2.11 2.04-2.08 2.07-2.11 2.04-2.12
?
4.01 4.08
4.02
3.97
CH2Cl (s)
aFrom the signal of an internal standard of Me&i for solutions in chloroform-d. *lH-n.m.r. data for 8 and 10 are given in ref. 6. CMultiplicity in parentheses. dThesignals for&5band H-5’b are comparatively and respectively at a higher field than those for H-5a and H-5/a. CJH-n,m,r. spectra are given in ref. 8.
T [a-D-(134)] 11” [B-D-(1+4)] 12s
6”
1 2 3 46 5
cotnpo fofd
JH-CHEMICAL SHIFTS”(S) OFD-XYLODJOSES l-7, 9,11, AND 12”
TABLE I
w
1 2 3 4 5 6 7 9 11 12
* 7.25 6.75 5.50 5.40 6.00 6.00 5.50 7.00 7.00 7,25
Jr,2
9.00 8.25 6.50 6.50 7.25 7.25 7.00 8.25 8.50 8.50
Ja,s
9.00 8.25 6,50 6.50 7,25 7.25 6,65 8.25 8050 8.60
534
5.37 5.00 4.00 4.00 4.50 4.50 4.00 5.00
J1,KO
9.30 8.50 6.50 6.50 7.00 7.00 6.50 9.00 9.50 8.85
12.00 11.75 12.50 12.50 12.00 12.00 12.50 12.00 12.00 11.80
Jrin,sb
11, AND 12
J4,sb
1H-N.M,R.COLPLIWO-CONSTANTS (Hz) OFD-XYLODIOSES l-7,9,
TABLE II
3.75 6.00 3.75 3.75 6.25 6825 6.00 3.75 6000 6,OO --_-
J1#,21
10,Oo 7.75 10.00 10.00 7.75 7.75 7,55 WJO 7.50 8.00
J2',3'
-
5,47 4.50 600 6,OO 4,5O 450 4,60 6,OO 4.50 4,70
9.75 7.75 IO,00 10.00 7.75 7.75 7.30 10,OO 7,5O 7.85 -
JS’,ti’l7
J3',4'
11.50 7.50 11.00 11.00 7.75 7.75 7.20 11,Oo 3.00 8.25
Jd,db
---
11.06 12.00 11.00 11.00 12.00 12,oo 12,OO 11.00 12.00 11.80
h’n,5’b
ro’ I ?
“2
H
.” $ g
P
N.M.R.
OF D-XYLOBIOSES
Fig. 1. lH-N.m.r. xylopyranose (1).
spectrum of
1,3,~tri-O-aCetyl-2-0-(2,3,4-tri-0-acety~-~-D-X~~O~~~OS~~)-~-D-
I
I
5.73
Fig. 2. lH-N.m.r. xyloPyrano= (2).
3.42
spectrum of
5.79
Fig. 3. lH-N.m.r. xyloPyrano= (3).
1,3,4-~-0-acetyl-2-O-(2,3,dtri-O-acetyl-~-~xylop~osyl)-~-D-
353
spectrum of
P.P
1,2,Q-tri-O-acetyl-3-O-(2,3,4-tri-O-acetyl-~-~-~lop~nosyl)-~-~
Comparison of the spectra of the six hexa-0-acetyl disaccharides showed a good similarity between the chemical shifts of the protons belonging to nonreducing residues for disaccharides having a 8-D linkage (slightly perturbed, neighbouring giycoside linkage), whereas for compounds having an a-~ linkage differences of 6 0. E-O.20 were observed. It is known that, for a-o-linked disaccharides, the rotational angle 4 around the C-l’-0 bond of the glycoside linkage may be less restricted than that of the /3-D-linked disaccharides, which allows a wider environment_ The differences
pp.1
6
J.-P.UTILLE, P. J. A. VOTTERO
1
5'b
AA
6
5.70
3.41
Fig. 4. lH-N_m.r_ spectrum of xylopyranose (5).
P-P.1
1,2,~tri-O-acetyl-3-O-(2,3,etri-O-acetyl-~-~-xylop~nosyl)-~-~-
reported herein for the proton chemical shifts of the nonreducing unit of a-D-xylobioses may suggest an “exe-anomeric effect”‘. the position of the H-x signal relative For each glycoside linkage (C-l ‘+0-x), to those of H-5 and -5’ is characteristic of the glycoside linkage; for the B-D configuration, the H-x signal is located between those of H-5’a and -5a, and H-5b and -5’b; for the a-D configuration, it is located between that of H-5a and those of the group H-5’a, ..5b, and -5’b. The proton H-5’b exhibited a signal similar to a triplet ( J4ew5sb,N J Sna,Srb)for the a-D, and a doublet of doublets for the /I-D configuration. The chemical shifts of H-l’ or H-x, or of both, are not very characteristic of the nature of the (C-I’-sO-x) linkage, when compared to those observed in ‘3C-n.m.r. spectroscopy. 13C-N.m.r. - The signals of the carbon atcms were assigned by a Aective, heteronuclear-decoupling technique on the basis of ‘H-n.m.r. data (Table III). By TABLE III ‘3c-CHEhXAL
SHIFI-S (6)”
OF REDUCING
XYLOBIOSES
1-12
conlpoluld
C-l
c-2
c-3
c-4
c-5
1 2 3 4 5 6 7 8b 9 1W 11 12
93.84
92.80 91.81 91.98 92.07 92.05 92.22 92.00 91.95 92.41 92.22 92.34
74.38 76.61 69.45 69.72 70.13 70.03 7Q.40 70.15 70.03 70.13 70.01= 70.01
72.34 72.77 73.70 74.08 76.90 77.22 76.71 73.21 73.11 72.19 72.02 72.17
68.98 68.65 69.01 69.23 68.62 68.60 68.87 72.97 73.02 74.33 74.25 74.W
63.06 62.97 61.61 61.73 62.36 62.36 62.41 64.30 64.21 63.50 63.33 63.45
C-l' 95.40 100.86 96.00 96.15 101.03 101.Ol 101.18 96.51 96.4499.74 99-43 100.06
c-2’
c-3’
c-4
c-s
71.07 70.13 71.05 70.91 70.25 70.18 72.70 70.86 70.69 70.66 70.10= 70.61
69.13 70.68 69.21 71.41 70.81 72.73 71.22 69.08 68.82 70.78 69.91 74.47~
68.98 68.77 69.01 68.84 68.62 68.36 71.51 69.01 70.57 68.57 69.91 67.97
58.74 61.73 59.03 59.08 61.83 61.78 61.78 58.82 57.48 61.83 61.15 64.76
“From the siml of an internalstandardof Me&i for soIutions in chloroform-d; Spectra are given in ref. 8. bSeeref. 6. CChemicaEshift values of C-2 and -2’ for 11, and C-4 and -3’ for 12 may be transposed.
-0.27
to.12
-0.15
5 G-D) 10 V-D)
to.07
3’-OAc 4’-
9 @f-D) 11 (8-D) -0.05
to.05
-0.25 -0.22
-0.08
-0.09 -0.17
to.12
C-5
to.05
- 0.02
to.22
c-4
-0.15 -0.32
-0.02 -0.07 -0,31
to.15
C-l’
to.os
-2.93 to.60
-0.41 -3.69
-2.45 -1-0.05
-0.68
-0.05 -0.34
t 0.05
C-5’
-2.89
-1-2.20 -0.17 i-1.92 -0.26 -0.26 $1.56 -0.87 $1.34
-0.14 -0.07 -0.17 -0.56
C-4’
C-3’
C-2’
aDifferencebetweenthe shift position of a particularcarbon atom in any O-chloroacctyl-o-xylobiose derivativeand the resonanceof the equivalentcarbon atom in the parent hexa-O-acetyl-D-xylobiose. “Differencebetweenthe shift position of a particular carbon atom in hexa-CSacetyl-o-xylobioses 5 and 10 and the resonance ofthe equivalent carbon atom in the respectiveparent penta-0-acetyl-D.xylobioses 7 and 12.
to.02
i-o.19
i-O.32 -0.10 -0.17
$0.38
1-0.27 -0.10 -0.12 -0,12
-0.02 -0.05 -0.19
to.17
3’.OCOCHzCl 3’4’4’-
4(&D)
6 @D)
c-3
c-2
C-l
Compound
SubstitNent
CHEMICALSHlFTS(d)INDUCED ~YSUBSTITUTIONWITHCHLOROAC@TYLaORACETYLbOROUPS
TABLEIV
8
J.-P.
UTILLE,
P. J. A.
VOTTERO
use of 62.86-MHz spectroscopy, it was possible to assign almost all the peaks, some tentative interpretations being cotirmed on the basis of ester-group effects. It is well known that substitution of an acetyl group by a more electronegative group, such as the trichloroacetyl groupg, produces a general deshielding effect on the corresponding ring carbon-atom, and a shielding effect on the two neighboring ring carbon-atoms, as was observed for an octa-O-acetylgentiobiose derivative”. Esterification by a chloroacetyl group showed, in smaller magnitudes, an a effect in the range of 6 + 1.3-2.2 and a slight p effect of less than S -0.7 (Table IV). The influence of the substituent located in the nonredilcing residue takes place through bonding electrons rather than space, as no modification of the chemical shifts for the carbon atoms of the reducing part of the disaccharide was observed. On the other hand, comparison (Table IV) of the chemical shifts of carbon atoms of hexa-O-acetyl disaccharides with those of homologous penta-O-acetyl derivatives (free hydroxyl group in the nonreducing unit of 7 and 10) corroborates the effects that have been observed for O-acetyl groups in the D-xylopyranose series” and for L-rhamnose acetatesi’. The availability of all these reducing disaccharides allowed a comparison between the chemical shifts of the signals of C-l ’ atoms, the glycoside configuration, and the nature of the linkage C-1’-O-C-x (Table V). Each C-l and -1’ showed a specific shift relative to the glycoside linkage, with a set of values for the a-D configuration between 6 95.40 and 96.51 and for the B-D configuration between 6 99.74 and 101.03. However, it should be made clear that signals for C-l ’ atoms involved in the /3-D-(l’j2) and p-D-(1’-+3) linkages (2 and 5) are separated by not more than 6 0.17. Nevertheless, taking into account the general pattern of the C-l ’ signals, these signals TABLE
V
13c-CHEhlICAL
SHIFTS
OF c-1’
FOR
A c-l’-o-c-X
LIN?ZAGEO
_
c0nIp011nd
Linkpge
C-Pa
1 2
(1’+2)
95.40
3 4 5 6 7
(1’+3)
8 9
(1’+4j
C-I’~
C-X
100.86
74.38 76.61
101.03 101.Ol 101.18
73.70 74.08 76.90 77.22 76.71
96.00 96.15
96,51 96.44
10 11 12
“For 1-2, x = 2; for 3-7, x = 3; for S-12,x = 4.
99.74 99.43 100.06
72.97 73.02 74.33
74.25 74.55
N.M.R.
OF D-XYLOBIOSES
9
may he used to identify the nature of the glycoside linkages in oligo- or poly-D-xylose structures as per-0-acetyl derivatives. As co&d be expected, substitution at O-2, -3, and -4 of the reducing unit by a D-xylopyranosyl residue resulted in a great downfield shift of the corresponding signal (see Table V). These signaIs, which are generally more difficult to observe than those of the C-l atoms in analysis of mixtures of oligosaccharides or polysaccharides of complex structures, may ,however, bring complementary information and ronsrmation of the assignments. EXPJ3UMENTAL
The ‘H- and ‘3C-n.m.r. spectra were recorded with a Kameca apparatus at the Centre Grenoblois de Resonance Magnetique (France). The disaccharides were examined in solution in chioroform-d at 20”. Chemical shifts were measured relative to the signal of tetramethylsilane, used as internal reference_ For ‘H-n.m.r. spectroscopy, attribution of the signals was made by selective irradiation or Indor experiments; the chemical shifts and coupling constants were measured on a 600-Hz scale-width for spectra recorded at 250 MHz with tubes of 5-mm o.d. Proton-decoupled, 13C-n.m.r. spectra were obtained at 62.86 MHz with tubes of 8-mm o.d. by Fourier-transform experiments (16 k memory; pulse width, 13 ps, z-90”; acquisition time, 0.6; spectral windows, -200 p_p_m.; and enlargement, c-50 p.p_m.). Attribution of 13C signals was made by selective, heteronucleardecoupling experiments. General methods. -
ACKNOWLEDGMENTS
The authors thank Prof. D. Y. Gagnaire for helpful discussions, and the Centre Grenoblois de Resonance Magnetique for recording the ‘H- and ‘3C-n.m.r. spectra. REFERENCES 1 2 3 4
G. E~COFRER AND J.-P. Urru~, unpublished results. B. HELFERICH AND J. ZIRNER, Chem. Ber., 95 (1962)26042611. C. S. HUDSON AND J_ M. JOHNSON, J. Am. Chem. Sot., 37 (1915)2748-2752. J.-P. UTILLE ANDP. J. A. VO’ITERO, Curbohydr_ Res., 52 (1976) 241-245. 5 J.-P. UTILLE AND D. Y. GAGNAIRE, Carbohydr. Res., unpublished results. 6 J.-P. UTILLE ANDP. J. A. Vomo, Carbohydr_ Res., 53 (1977)259-262. Curbohydr_ Res., 65 (1978) 114-120. 7 S.P&EZANDR.H.MAR cHEssAUL.T, 8 J.-P. UTILLE, PGparation par synth& chimique ou par hydrolye aci’de de xy/ane.s, des oligom&es
de la s&ie du D-xylose. &de de ces composks et des polysaccharides correspondants par r.m.n, du proton et du carbone, TJ&e d’lht, Universitede Grenoble(France),1979. 9 M. R. VIGNON ANDP. J. A. Vomo, Tetruhedron I.&t., (1976) 2445-2448. 10 M.R. VIGNONAND P. J. A.V -0, Carbohydr_ Res., 53 (1977) 197-207. 11 J.-P. UW ANDP. J. A. Vomo, Curbohydr_ Res., 85 (1980) 289-297. 12 V. POZSGAY AND A. Neswrf~q Carbohydr. Res., 80 (1980) 196-202.