John D. Stevens

Selective deuteration over raney nickel in deuterium oxide: Methyl glycosides

Abstract The rate of protium-deuterium exchange, catalyzed by deuterated Raney nickel in deuterium oxide, in various positions in methyl glycopyranosides and furanosides has been studied. In general, the exchange process is not highly regio-selective in these compounds. However, conditions were found under which methyl β- d -fructopyranoside can be selectively labelled on C-5, methyl β- d -fructofuranoside on C-3, and methyl β- d -galactopyranoside on C-3 and C-4.

A simple preparation of the 2,3:5,6- and 3,4:5,6-di-O-isopropylidene derivatives of d-glucose dimethyl acetal

Abstract The title compounds have been prepared in good yield directly from d -glucose. Separation of the isomers is achieved by selective crystallization of their benzoates.

An x-ray crystallographic study of 5-Oacetyl-1,2:3,4-di-O isopropylidene-α-d-galactoseptanose

Abstract Three-dimensional, single-crystal X-ray diffraction methods were used to determine the solid-state structure of 5- O acetyl-1,2:3,4-di- O -isopropylidene-α- d -galactoseptanose. The crystals are tetragonal with cell dimensions: a  b  9.571 (5), c  16.944(5) A, α  β  γ  90°, and z  4. The space group is P41 1 . The structure was solved by direct methods and refined by least-squares techniques to give a conventional discrepancy-factor, R , of 0.040. The seven-membered ring is close to a boat conformation, 1,2,5 B.

Selective deuteration over Raney nickel in deuterium oxide: 1,6-anhydrohexoses

Abstract The relative rates of protium-deuterium exchange, catalysed by deuterated Raney nickel in deuterium oxide, in various positions of 1,6-anhydrohexopyranoses and -furanoses have been studied. Conditions have been found under which 1,6-anhydro-β- D -galactopyranose may be labelled on C-3 and 1,6-anhydro-α- D -galactofuranose on C-2.

Septanose Carbohydrates. VII. Preparation of Mono-O-isopropylidene Derivatives of Methyl β-D-Glucoseptanoside and Preparation of Methyl α-L-idoseptanoside and its Derivatives

Three mono-O-isopropylidene derivatives of methyl β-D-glucoseptanoside have been prepared by acid-catalysed hydrolysis of methyl 2,3 : 4,5-di-O-isopropylidene-β-D-glucoseptanoside or by acetonation of methyl β-D-glucoseptanoside. Two of these derivatives have been used for the preparation of methyl 2,3-O-isopropylidene-α-L-idoseptanoside (8a) and methyl 3,4-O-isopropylidene-α-L-idoseptanoside (10a). Hydrolysis of (10a) yielded methyl α-L-idoseptanoside (12a) and acetonation of (8a) and (12a) yielded methyl 2,3 : 4,5-di-O-isopropylidene-α-L-idoseptanoside. Possible conformations of these compounds are discussed.

Structure and solution equilibria of D-glucose and D-mannose sulfite adducts.

An X-ray crystallographic study has confirmed that the potassium bisulfite adducts of D-glucose and D-mannose have open-chain structures with R and S configurations respectively at C-1. NMR studies have shown that each sugar gives rise to two bisulfite compounds, and solution-state structures and conformations of these isomers have been deduced from analysis of (1)H NMR spectra. (13)C NMR data for the four adducts are given. Furanose forms of the D-glucose and D-mannose have been detected in the equilibrium solutions.

Preparation of 1,2-O-isopropylidene derivatives of α-d-galactoseptanose, β-l-altroseptanose, and 3-O-methyl-α-d-guloseptanose

Abstract Displacement of the tosyloxy group in 5- O -benzyl-1,2- O -isopropylidene-4- O -( p -toluenesulfonyl)-α- d -glucoseptanose has yielded derivatives of 1,2- O -isopropylidene-α- d -galactoseptanose. Acid catalysed acetonation then gave 1,2:3,4-di- O -isopropylidene-α- d -galactoseptanose or 1,2;4,5-di- O -isopropylidene-α- d -galactoseptanose using lower acid concentrations. Reduction of the ketone derived from 1,2:3,4- O -isopropylidene-α- d -septanose gave 1,2;3,4-di- O -isopropylidene-β- l -altroseptanose. Reaction of 3,4-anhydro-5- O -benzyl-1,2- O -isopropylidene-α- d -galactoseptanose with sodium methoxide gave 5- O -benzyl-1,2- O -isopropylidene-4- O -methyl-α- d -glucoseptanose and 5- O -benzyl-1,2- O -isopropylidene-3- O -methyl-α- d -guloseptanose. Solution-state conformations of these compounds have been deduced from their 1 H NMR spectra.

A general survey of proton spin-lattice relaxation-rates for pentopyranose acetates

Abstract A survey has been made of the spin-lattice relaxation-rates at 100 MHz of the ring protons of all eight of the d -pentopyranose tetra-acetates and of methyl α- d -xylopyranoside triacetate. Qualitative intercomparisons clearly demonstrate the diagnostic utility of these R 1 -values for configurational assignments.

Non-selective, proton spin–lattice relaxation rates measured at 400 mhz: a quantitative determination of the geometry of diamagnetic molecules in solution

Initial slope, non-selective, spin–lattice relaxation rates have been determined at 400 MHz for 1,2,3,4-tetra-O-acetyl-β-D-arabinopyranose (1) and for its 5,5-dideuterio derivative (2) and its two isomeric 5-deuterio derivatives (3) and (4); simple comparisons of these data give the specific interproton relaxation contributions arising via the dipole–dipole mechanism, from which the magnitudes of interproton distances can be calculated, the values of which are in very close agreement with values obtained by neutron diffraction.

Preparation of α- and β-D-glucoseptanose pentaacetates.

The α- and β-D-glucoseptanose pentaacetates have been prepared by treatment of ethyl 1-thio-β-D-glucoseptanoside tetraacetate with mercury(II) acetate in acetic acid. The solid state structure of the β-isomer has been determined by X-ray diffraction.