The structure determination and molecular-mechanics calculation of 1,6-anhydro-β-D-galactopyranose

Ceccarelli, C.; Ruble, J. R.

doi:10.1107/s0567740880004700

Cited by 19 publications

(4 citation statements)

References 8 publications

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“…1993, 12, 801-804), but the reported 3 JH5,H6R (9.5 Hz) and 3 JH5,H6S (1.5 Hz) suggest that the geometry is either distorted or conformationally averaged. 25 and JHH values were taken from ref 26. d Defined as O5-C5-C6-O6 in 2-4 and O4-C5-C6-O1 in 1. e Defined as C5-C6-O6-CX in 2-4 and C5-C6-O1-C2 in 1.…”

Section: Results and Discussion (A) Choice Of Model Compounds Compoundsmentioning

confidence: 99%

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Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of ²J_HH, ³J_HH, and ¹J_CH Spin−Spin Coupling Constants

et al. 2002

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Experimental and theoretical methods have been used to correlate (2)J(HH) and (3)J(HH) values within the exocyclic hydroxymethyl groups (CH(2)OH) of saccharides with specific molecular parameters, and new equations are proposed to assist in the structural interpretation of these couplings. (3)J(HH) depends mainly on the C-C torsion angle (omega) as expected, and new Karplus equations derived from J-couplings computed from density functional theory (DFT) in a model aldopyranosyl ring are in excellent agreement with experimental values and with couplings predicted from a previously reported general Karplus equation. These results confirm the reliability of DFT-calculated (1)H-(1)H couplings in saccharides. (2)J(HH) values depend on both the C-C (omega) and C-O (theta) torsions. Knowledge of the former, which may be derived from other parameters (e.g., (3)J(HH)), allows theta to be evaluated indirectly from (2)J(HH). This latter approach complements more direct determinations of theta from (3)J(HCOH) and potentially extends these more conventional analyses to O-substituted systems lacking the hydroxyl proton. (1)J(CH) values within hydroxymethyl fragments were also examined and found to depend on r(CH), which is modulated by specific bond orientation and stereoelectronic factors. These latter factors could be largely, but not completely, accounted for by C-C and C-O torsional variables, leading to only semiquantitative treatments of these couplings (details discussed in the Supporting Information). New equations pertaining to (2)J(HH) and (3)J(HH) have been applied to the analysis of hydroxymethyl group J-couplings in several mono- and oligosaccharides, yielding information on C5-C6 and/or C6-O6 rotamer populations.

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Section: Results and Discussion (A) Choice Of Model Compounds Compoundsmentioning

confidence: 99%

“…b In Hz, ± 0.1 Hz, in 2 H 2 O, 30 °C. c Torsion angles were obtained from the crystal structure, and J HH values were taken from ref . d Defined as O5−C5−C6−O6 in 2 − 4 and O4−C5−C6−O1 in 1 .…”

Section: Resultsmentioning

confidence: 99%

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of ²J_HH, ³J_HH, and ¹J_CH Spin−Spin Coupling Constants

et al. 2002

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“…Like the cyclic alkanes, these are molecules with rigid conformations which can be predicted very successfully by standard methods of molecular mechanics (cf. Engler, Andose &von Schleyer, 1973;Jeffrey & Park, 1979;Ceccarelli, Ruble & Jeffrey, 1980). The molecules have a higher ratio of ether oxygens to hydroxyls than the pyranoses and pyranosides, which influences the intermolecular hydrogen bonding as illustrated by the crystal structure of 1,6-anhydro-fl-D-galactopyranose (Ceccarelli et al, 1980).…”

Section: The Anhydro Sugarsmentioning

confidence: 99%

Crystallographic studies of carbohydrates

Jeffrey¹

1990

Acta Crystallogr B Struct Sci

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151

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The monosaccharides which constitute the monomer units of many important industrial and biological macromolecules are well represented among the 2000 crystal structures of the carbohydrate class 45 of the Cambridge Structural Database. There are few examples of crystal structure analyses of the corresponding acids, but many of their calcium salts and calcium salt complexes. With the exception of the disaccharides and cyclodextrins, the oligosaccharides are not well represented, with less than ten trisaccharides, one tetrasaccharide and one hexasaccharide-iodide complex. Two important conformational factors are the Hassel-Ottar effect and the anomeric effect, both of which have been studied using crystallographic data. Hydrogen bonding is ubiquitous in carbohydrate crystals and generally involves all the hydroxyls as both donors and acceptors, and some of the ring and glycosidic oxygens as acceptors. These hydrogen bonds tend to form finite or infinite chains. In hydrates, these chains are linked through the water molecules to form networks. Cyclic hydrogen-bond systems are observed in the cyclodextrins. Long-chain alkylated carbohydrates provide a large class of thermotropic and lyotropic liquid crystals, and some non-ionic surfactants which have been shown to be useful for membrane-protein solubilization and crystallization.

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“…13 The atom arrangement and the numbering system for 8 are shown in Figure 1.Selected bond angles and lengths are given in Table 2. The crystal structures of 7 13 and 1,6-anhydro-ß-D-galactopyranose 15 have been previously determined. The Sn-C bond lengths fall in the narrow ranges 2.132(11) to 2.146 (7).…”

Section: Conformations In Solutionmentioning

confidence: 99%

Some Stannylated Galactose Derivatives

Garden¹,

Wardell²,

Melvin³

et al. 1996

Main Group Metal Chemistry

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The synthesis and NMR spectra of l,2:3,4-di-0-isopropylidene-6-O-[(3-triphenylstannyl)propyl]-a-D-galactopyranose (4), 3-(triphenylstannyl)propyl a-D-galactopyranoside (6), obtained by hydrostannation of 6-0-allyl-l,2:3,4-di-0-isopropylidene-a-D-galactopyranose (3) and allyl a-D-galactopyranoside (5), respectively, and l,6-anhydro-3,4-0-isopropylidene-2-O-[(triphenyl-stannyl)methyl]-ß-D-galactopyranose (8), produced from Ph 3 SnCH 2 I and 1,6anhydro-3,4-0-isopropylidene-ß-D-galactopyranose (7), are reported. The solution conformations of the carbohydrate rings in 4, 6, and 8 are similar to those in the non-stannylated precursor molecules, 3, 5 and 7. Furthermore, an X-ray diffraction study of 8 indicated a similar carbohydrate core structure to that found for solid 7: the tin centre in 8 has a tetrahedral geometry. Both the mono-iodotin derivatives, l,6-anhydro-2-0-[(iododiphenylstannyl)methyl]-3,4-0isopropylidene-ß-D-galacto-pyranose (12), and [3-(iododiphenylstannyl)propyl] a-Dgalactopyranoside (11) are 4-coordinate species in solution; in contrast, 6-<9-[3-(iododiphenylstannyl)propyl]-l,2:3,4-di-0-isopropylidene-a-D-galactopyranose (9) is a 5-coordinate species in CDC1 3 solution. The sugar unit in 9 is thus a more effective chelating ligand than are either of the sugar units in 11 and 12. INTRODUCTION.We recently reported 1 the synthesis and NMR spectra of a family of 6-0-[(l,2:3,4-di-0-isopropylidene)-a-D-galactopyranosyl)]methyl-tin compounds, (1). The crystal structure of one member of this series, (1; η = 1, m = 0) 2 , has been determined, as has that of the monoiodo species, (1; m = 1, η = 2, R = I) 1 . These mono-, di-and tri-saccharide derivatives, (1), were obtained via the reactions of appropiate iodomethyltin reagents with l,2:3,4-di-0-isopropylidene-a-D-galactopyranose, (2). η •m-n ( 1 ) m = 0; η = 1-3 m = 1-3; n= 1; R = Me m = 3; n= 1; R = Bu 251 Brought to you by | Purdue University Libraries

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The structure determination and molecular-mechanics calculation of 1,6-anhydro-β-D-galactopyranose

Cited by 19 publications

References 8 publications

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of ²J_HH, ³J_HH, and ¹J_CH Spin−Spin Coupling Constants

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of ²J_HH, ³J_HH, and ¹J_CH Spin−Spin Coupling Constants

Crystallographic studies of carbohydrates

Some Stannylated Galactose Derivatives

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The structure determination and molecular-mechanics calculation of 1,6-anhydro-β-D-galactopyranose

Cited by 19 publications

References 8 publications

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of 2JHH, 3JHH, and 1JCH Spin−Spin Coupling Constants

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of 2JHH, 3JHH, and 1JCH Spin−Spin Coupling Constants

Crystallographic studies of carbohydrates

Some Stannylated Galactose Derivatives

Contact Info

Product

Resources

About

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of ²J_HH, ³J_HH, and ¹J_CH Spin−Spin Coupling Constants

Hydroxymethyl Group Conformation in Saccharides: Structural Dependencies of ²J_HH, ³J_HH, and ¹J_CH Spin−Spin Coupling Constants