Synthesis and Biological Effects of Acyclic Analogs of Deazapurine Nucleosides

Deaza analogs of three basic types of S-adenosyl-L-homocysteine hydrolase (SAHase) inhibitors, (S)-DHPA (I), eritadenine (II) and AHPA (III), were prepared. Alkylation of 3-deazaadenine (V), 3-deazapurine (VI), 1-deazaadenine (VII) and 4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidine (XXII) with (R)-2,2-dimethyl-4-tosyloxymethyl-1,3-dioxolane (XIIIb), followed by acid hydrolysis, afforded the corresponding (S)-2,3-dihydroxypropyl derivatives XVIIa -XIXa and XXV. Reaction of V and VII with 2,3-O-cyclohexylidene-D-erythrono lactone (XXIX) and subsequent removal of the protecting groups in an acid medium gave eritadenine analogs XXVII and XXVIII. Compounds V and VII were alkylated with bromoacetaldehyde diethyl acetal to give N-(2,2-diethoxyethyl) derivatives XXXII and XXXIII from which the substituted acetaldehyde derivatives were liberated in situ and converted into compounds XXX and XXXI by cyanohydrine reaction followed by acid hydrolysis. The alkylations were performed in dimethylformamide with sodium or cesium salts of the bases. Biological activity was observed only with 3-deazaadenine derivatives XVIIa, XXVII and XXX, which exhibit both enzyme-inhibitory and antiviral activities.