1952 Volume 72 Issue 1 Pages 1-3
From the alcoholic extract of the air-dried leaves of Hyptis capitata Jacq., a flavonol glucoside was obtained, besides potassium chloride, as yellow needles, m.p. 158-160° (anhydrate, m.p. 190-193°), corresponding to formula C27H30O15⋅4H2O. Hydrolysis of the glucoside with 5% sulfuric acid gave kaempferol, glucose and rhamr ose. Methylration of the glucoside with diazomethane, followed by hydrolysis with 5% sulfuric acid yielded an aglycone as yellow needles, m.p. 149-150°, which was proved different from 3, 7, 4′-trimethylkaempferol by mixed fusion. Difference in melting points showed that the aglycone could not be either 3, 5, 4′- (m.p. 283-284°) or 3, 5, 7-trimethylkaempferol (m.p. 280-281°). This led to the assumption that the aglycone must be 5, 7, 4′-trime-thylkaempferol and the original glycoside, kaempferol-3-rhamnoglucoside. In order to obtain material for comparison, 4′-benzyloxy-3-methoxy-5, 7-dihydroxyf lavone, yellow plates, m.p. 279-280°, was prepared by the method of Allan and Robinson, methylated with diazomethane to 4′-benzyloxy-3, 5, 7-trimethoxyf lavone, colorless needles, m.p. 155-156°, and debenzylated with conc. hydrochloric acid to 4′-hydroxy-3, 5, 7-trimethoxy-flavone, pale yellow plates, m.p. 280-281°. Acetate, m.p. 152-153°.