The 1st chemical syntheses of the arabinosylhypoxanthine and arabinosylguanine analogues of the imidazo[1,2-c]pyrimidine series are described. Condensation of trimethylsilyl-7-chloroimidazo[1,2-c]pyrimidin-5-one with 2,3,5-tri-O-benzyl-.alpha.-D-arabinofuranosyl chloride gave 7-chloro-1-(2,3,5-tri-O-benzyl-.beta.-D-arabinofuranosyl)imidazo[1,2-c]pyrimidin-5-one (3), which on catalytic dehalogenation furnished 1-(2,3,5-tri-O-benzyl-.beta.-D-arabinofuranosyl)imidazo[1,2-c]pyrimidin-5-one (4). Amination of 3 gave 7-amino-1-(2,3,5-tri-O-benzyl-.beta.-D-arabinofuranosyl)imidazo[1,2-c]pyrimidin-5-one (5). Reductive hydrogenolysis of 4 and 5 gave 1-(.beta.-D-arabinofuranosyl)imidazo[1,2-c]pyrimidin-5-one, the arabinosylhypoxanthine analogue and the corresponding 7-amino isomer, the arabinosylguanine analogue, respectively. The unequivocal assignment of the site of glycosylation and the anomeric configuration were established. None of the compounds exhibited significant antiviral or antimicrobial activity in vitro.