(E)-1-Benzyl-1,4-dihydro-4,6-dimethyl-7-(3-methyl-1-butenyl) {-9H-imidazo[1,2-.alpha.]purin-9-one} 1-Benzyl-4,6-dimethyl-7-(3-methyl-1-butenyl)-1,4-dihydro-9H-imidazo[1,2-a]purin-9-one AIDS-135240 AIDS135240 NSC634632