On the basis of a methylation study of N6-benzyl-9-methyl-8-oxoadenine (8), the first synthesis of caissarone hydrochloride (1) has been achieved via a two-step route including methylation of the N6-methyl analogue (3).
Purines. LVII. Regioselective Alkylation of N6,9-Disubstituted 8-Oxoadenines: Syntheses of the Sea Anemone Purine Caissarone and Some Positional Isomers and Analogues.