Abstract
Acyclic acetal derivatives of the selective antiherpesvirus agent 9-(3-hydroxypropoxy) guanine (BRL44385) and of its 2-aminopurine congener (BRL46720) have been prepared and evaluated in mice for oral delivery of BRL 44385. Guanine derivatives (6 a-c) were prepared via Mitsunobu condensation of an alcohol with a 9-hydroxy-6-methoxypurine (Harnden and Wyatt, 1990). Synthesis of derivatives of 2-aminopurine (10 a-d) was achieved by hydrogenolysis of 9-alkoxy-6-chloropurines, which were obtained either by reaction of an alkoxyamine with 4,6-dichloro-2,5-diformamidopyrimidine and subsequent ring closure or by Mitsunobu condensation of an alcohol with a 6-chloro-9-hydroxypurine. Following oral administration, 2-amino-9-[3-(iso-propoxymethyl)propoxy]-purine (10b, BRL 55792) was very well absorbed and provided high and prolonged concentrations of BRL44385 in the blood. In a cutaneous HSV-1 infection in the ear pinna of mice, orally dosed BRL 55792 was at least 3-fold more potent than both BRL44385 and Acyclovir in reduction of lesion severity.