|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1990 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1989 : ¥1,100,000 (Direct Cost : ¥1,100,000)
1. The first total synthesis of 6-imino-1, 9-dimethy1-8-oxopurine (I), a constituent of the marine sponge Hymeniacidon sanguinea Grant, has been achieved via two alternative routes starting from 8-bromo-9-methyladenine (II), which is obtainable from 9-methyladenine (III) by bromination. The first route includes methylation of II with MeI to give 8-bromo-1, 9-di-methyladenine (IV) and treatment of IV with NaOAc in boiling AcOH to produce I in 25% overall yield (from III). The second route includes treatment of II with boiling 1 N aqueous NaOH and methylation of the resulting 8-oxo derivative with MeI, affording I in 63% overall yield (from III).
2.The reaction rates in the Dimroth rearrangements of the marine sponge base 6-imino-1, 9-dimethyl-8-oxopurine (I) and related compounds such as 1, 9-dimethyladenine (V) and 8-bromo-1, 9-dimethyladenine (IV) were measured in H_2O at various pH's and ionic strength 1.0 at 40^ﾟC. In all cases, attack of hydroxide ion on the protonated species of the substrate at the 2-position was faster than that on the neutral species by a factor of 100-1400. In the reaction of the protonated species, the relative ease of undergoing Dimroth rearrangement was in the order of IV > V > I. The same order of reactivity was found to hold for the neutral species.
3.The first chemical synthesis of caissarone hydrochloride, a constituent of the sea anemone Bunodosoma caissarum Correa 1964, has been accomplished via a two-step route including methylation of N6, 9-dimethyl-8-oxoadenine. This synthesis was based on a methylation study of N^6 -benzy1-9-methy1-8-oxoadenine.