A series of 2, 4-diamino-5-(3, 5-dialkenyl-4-methoxy-or-4-hydroxybenzy1) pyrimidines was prepared from [(allyloxy) benzyl] pyrimidines by Claisen rearrangements, and the resulting allyl phenols were further modified by methylation and rearrangement to 1-propenyl analogues. Analogous 3, 4-dimethoxy-5-alkenyl derivatives were prepared by similar techniques. High in vitro antibacterial activity was obtained against certain anaerobic ...