Patent ID: 7361745
Filing Date: 2008-04-22
Classification: C07H

Abstract:
1. Process for the preparation of 1-chloro-3,5-di-O-acyl-deoxy-L-ribofuranosidic derivatives of formula (I) wherein R is an acyl group R′CO, in which R′ is selected from the group consisting of alkyl groups C1-C6 and aryl groups C7-C13, possibly substituted with one or more substituents; said process comprising the following steps: i) reaction of 2-deoxy-D-galactose of formula (II) with methanol in the presence of an acid as catalyst to obtain the 1-O-methyl-2-deoxy-D-galactofuranoside of formula (III): ii) oxidation of 1-O-methyl-2-deoxy-D-galactofuranoside of formula (III) coming from step i) with sodium meta periodate to obtain the corresponding aldehyde of formula (IV): iii) reduction of the aldehyde of formula (IV) coming from step ii) with sodium borohydride to obtain the 1-O-methyl-2-deoxy-L-ribofuranoside of formula (V): iv) acylation of O-methyl-2-deoxy-L-ribofuranose of formula (V) coming from step iii) with an acyl chloride of formula R′COCl, in presence of a tertiary amine base in an aprotic solvent to obtain the corresponding 1-O-methyl-3,5-di-O-acyl-2-deoxy-L-ribofuranoside having formula (VI): in which R′ and R are defined as above; v) chlorination of 1-O-methyl-3,5-di-O-acyl-2-deoxy-L-ribofuranoside of formula (VI) coming from step iv) with gaseous hydrochloric acid at a temperature lower than 20° C. to obtain 1-chloro-3,5-di-O-acyl-2-deoxy-L-ribofuranoside of formula (I): where R is defined as above.