Search

Melicopicine and normelicopicine undergo oxidative demethylation with nitric acid giving rise to isomeric dimethoxyquinones. These are further demethylated by alkali to the same hydroxymethoxyquinone which is converted by hydrobromic acid to a dihydroxyquinone. All the quinones can be reductively methylated back to melicopicine.

Among the constituents of the bark of Melicope sarcococca Laut. (Rutaceae) have been found two optically active flavanones : (-)-4',5-dihydroxy-3',7-dimethoxy-flavanone, and its 4'-prenyl ether. The occurrence of the flavanone prenyl ester is of interest in view of the occurrence of coumarin and furocoumarin isoprenoid ethers in the family Rutaceae.

From the leaves of Melicope perspicuinervia Merr. & Perry the following substances were isolated: skimmianine, kokusaginine, (�)-platydesmine, halfordinine, piperonylic acid, α-onocerin, β-sitosterol, quercetin 3,3'-dimethyl ether and a new flavone, melinervin. The latter was shown to be 3,5,7-trihydroxy-6,8-dimethoxy-3',4'-methylenedioxyflavone by its spectroscopic properties and by synthesis. Halfordinine was shown to be 6,7,8-trimethoxydictamnine by degradative methods.

The bark of Acronychia Baueri Schott yields four alkaloids, three of which, melicopine, melicopidine, and acronycidine, occur in Melicope fareana(1). The fourth is a new alkaloid acronycine, C20H19O3N. The leaves yield a fifth alkaloid, melicopicine, also present in Melicope fareana.

2,4,6-Trihydroxybenzoic acid was converted by partial methylation, formylation, and then reduction into methyl 2-hydroxy-3-hydroxymethyl- 4,6-dimethoxybenzoate (5) which proved different from dimethyldegeranylmelicopol. Methyl 6-geranyloxy-2-hydroxy-3- hydroxymethyl-4-methoxybenzoate (4), its neryl analogue (7), and methyl 4-geranyloxy-2-hydroxy-3-hydroxymethyl-6-methoxybenzoate (21) were prepared similarly but all were different from methylmelicopol. From a re-investigation of earlier work, melicopol and methylmelicopol were assigned new structures, 6?-geranyloxy-2,2?,4?-tri-hydroxy-3?- methoxyacetophenone (31) and its 4?-methyl ether derivative (24), respectively. Dimethyldegeranylmelicopol, 2,6?-dihydroxy-2?,3?,4?- trimethoxyacetophenone (25), was prepared from antiarol (28) and acetoxyacetonitrile.

A new flavanone has been isolated from the bark of Melicope sarcococca Laut. (Rutaceae), the structure of which has been found to be 5-hydroxy-7,3'-dimethoxy-4'-(3,6-dimethylhept-2-enyloxy)flavanone (III). The presence of the C9 rather than a C10 carbon atom alkenyloxy group is unusual but is supported by evidence from proton magnetic resonance and degradation studies.