A revision of the structures proposed for the melicope extractives, melicopol and methylmelicopol

Abstract

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.