Process for the preparation of purine compounds and intermediates therefor.

摘要

A process for the preparation of compounds of formula (I), and pharmaceutically acceptable salts thereof: <CHEM> wherein R1 is hydrogen or CH2OH; R2 is hydrogen or, (when R1 is hydrogen), hydroxy or CH2OH; R3 is CH2OH or, (when R1 and R2 are both hydrogen), CH(OH)CH2OH; R4 is hydrogen, hydroxy, amino or OR5 wherein R5 is C1-6 alkyl, phenyl or phenyl C1-2 alkyl either of which phenyl moieties may be substituted by one or two halo, C1-4 alkyl or C1-4 alkoxy groups; and in which any OH groups in R1, R2 and/or R3 may be in the form of O-acyl, phosphate, cyclic acetal or cyclic carbonate derivatives thereof; which process comprises the reaction of a compound of formula (II): <CHEM> wherein R4 min is R4 or a group or atom convertible thereto and Rx is amino or protected amino; with a compound of formula (III): R3 min CHR2 min CHR1 min Q (III) wherein Q is a leaving group and R1 min , R2 min and R3 min are R1, R2 and R3 respectively or R1, R2 and/or R3 wherein the OH group(s) is/are in protected form; and thereafter converting R4 min when other than R4, to an R4 moiety or converting R4 min , when R4 to other R4; if necessary converting R1', R2' or R3' to R1, R1 and R3 respectively and optionally forming a pharmaceutically acceptable salt, O-acyl, phosphate, cyclic acetal or cyclic carbonate derivative thereof.