Abstract
The new method for synthesis of dihydrodictamnine, reported in the preceding paper, was applied to the synthesis of other alkaloids of the furoquinoline series and a satisfactory result was obtained. Condensation of 4-methoxy, 4, 5-dimethoxy, and 4, 5-methylenedioxy derivatives of 2-nitrobenzoic acid with α-acetylbutyrolactone in benzene with magnesium as a catalyst afforded α-(o-nitrobenzoyl) butyrolactone which was treated with diazomethane, forming three kinds of enol-methyl ether. Catalytic reduction of these ethers afforded the corresponding 2, 3-dihydroevolitrine, 2, 3-dihydrokokusaginine, and 2, 3-dihydromaculine in a fairly good yield. Bromination of dihydrokokusaginine and dihydromaculine with N-bromosuccinimide and subsequent dehydrobromination afforded kokusaginine and maculine.
