Purines. LXV. Preparatory study for the syntheses of the marine sponge purines agelasimines-A and -B: Synthesis and acetylation of their N(7)-benzyl analogues

Article abstract of DOI:10.1248/cpb.42.2461

Four-step synthetic routes from 3-methyladenine (10) to 7-benzyl-N⁶,3-dimethyladenine (1b) and 7-benzyl-1,2-dihydro-1,3-dimethyladenine (2b), selected as models for the marine sponge alkaloids agelasimine-A (1a) and agelasimine-B (2a), respectively, have been established. The key steps involved are regioselective methylations of 7-benzyl-3-methyladenine (8) and 7-benzyl-1,2-dihydro-3-methyladenine (11). The reaction of 1b with acetic anhydride in pyridine was found to give the monocyclic imidazole derivative 29b. A similar acetylation of 2b yielded the N⁶-acetyl derivative 20b. When treated with boiling H₂O, 20b afforded 7-benzyl-2,3-dimethylhypoxanthine (21b) and a compound inferred to be the dihydrohypoxanthine derivative 30. Probable pathways to 29b from 1b and to 21b and 30 from 20b are proposed.

Full text of DOI:10.1248/cpb.42.2461

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NII-Electronic Library Service

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NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service