Studies on ketene and its derivatives. CX. Synthesis of 1,3-dimethoxyfluoren-9-ones.
作者:JUN NAKANO、NOBUYA KATAGIRI、TETSUZO KATO
DOI:10.1248/cpb.30.2590
日期:——
The synthesis of 1, 3-dimethoxyfluoren-9-ones (7a-f) from ethyl 2-aryl-4, 6-dihydroxybenzoates (4a-d), prepared by the reaction of diketene with ethyl 3-aryl-3-oxopropionates (3a-d), is described. Reaction of diketene with 3a-d in the presence of sodium hydride in tetrahydrofuran gave 4a-d. Methylation of 4a-d with methyl iodide, followed by treatment with alcoholic sodium hydroxide, gave 2-aryl-4, 6-dimethoxybenzoic acids (6a-d). Cyclization of 6a-d with trifluoroacetic anhydride gave 7a-f.