The syntheses of acycloformycins and 5-amino-3-(2-hydroxyethoxy)-methylpyrazolo[4,3-d]pyrimidin-7(6H)-one, an analogue of the antiviral acycloguanosine

Abstract

Syntheses of the novel acycloformycin A (7), acycloformycin B (8), and 5-amino-3-(2-hydroxyethoxy)-methylpyrazolo[4,3-d]pyrimidin-7(6H)-one (9), an analogue of the antiviral acycloguanosine (4), are described. These syntheses involve as key intermediate isopropyl 3-hydroxymethyl-4-nitropyrazole-5-carboxylate (20) which was generated by treatment of isopropyl 5-methyl-1,4-dinitropyrazole-3-carboxylate (23) with triethylamine followed by aqueous acid.