Condensation of Z-deoxy-~-ribose with nitromethane gave, after deionization, a syrupy mixture of epimeric l-nitro-1,3-dideoxy-hexitols. Acid hydrolysis under Nef reaction conditions produced a mixture of 3-deoxy-~-glucose and 3-deoxy-m mannose, separable by cellulose chromatography or fractional crystallization. The glucose compound was characterized via the p-nitrophenylhydrazone and tetraacetyl derivatives. The 3-deoxy-~-mannose was characterized as the p-nitrophenylhydrazone and by conversion to 3-deoxy-D-mannitol and its pentabenzoate.
N OUR PROGRAM of synthesis of nucleosides I carrying an unusual sugar, it has been of interest to prepare a series of 3'-deoxyaldosyl purines. Suitable starting materials for a number of the required 3-deoxy-sugar moieties are the hexoses, 3-deoxy-~-glucose and 3-deoxy-D-mannose. It was anticipated that substantial quantities of these aldoses would be required, and the authors have sought a synthetic route which is conveniently short and amenable to adaptation to fairly large-scale preparation.
Until recently, procedures for the synthesis of 3-deoxyhexoses have been lengthy and have given inconveniently low yields. One of the routes to glycosidic derivatives of 3-deoxyglucose involved reductive opening of 2,3-anhydro intermediates. When methy1-2,3-anhydro-4,6-benzylidene-a-~allopyranoside was submitted to high-pressure hydrogenation, a mixture containing predominantly methyl-3-deoxyglucoside along with its 4,6-hexahydrobenzylidene derivative resulted (1). This route was re-evaluated by Richtmyer and Pratt (2) and led to the isolation of the desired 3-deoxy-~-glucose in crystalline form but low yield. A similar high pressure reduction of methyl -2,3anhydro -4,6benzylidenea-D-mannoside gave a mixture of 3-deoxymannosides corresponding to that obtained from the 2,3-anhydroalloside (3). When the 2,a-anhydromannoside was reduced with lithium aluminum hydride, however, methyl-4,6-benzylidene-3- deoxy-a-D-mannoside was obtained in 85% yield (2, 4). Subsequent acid hydrolysis gave 3deoxy-D-mannose in an over-all yield of 3% from These routes illustrate the reason for the previous relative inaccessability of 3-deoxyglucose and 3-deoxymannose. The routes are long, and hence involve both considerable work-D-glucose (4).