Reactions of Protoberberine-Type Alkaloids. I

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Abstract
Reduction of 2, 3-methylenedioxy-9, 10-dimethoxydibenzo [a] acridizinium chloride (I) with lithium aluminium hydride in dioxane or tetrahydrofuran afforded dihydroberberine (II) in a good yield. Application of methyl iodide to (II) in dichloromethane or chloroform solution gave 13-methyl-2, 3-methylenedioxy-9, 10-dimethoxydibenzo [a]-5, 6-dihydroacridizinium iodide (VIII), and 13-methyl-2, 3-methylenedioxy-9, 10-dimethoxydibenzo [a, g] quinolizidine (VII), and that of ethyl iodide gave 13-ethyl-2, 3-methylenedioxy-9, 10-dimethoxydibenzo [a, g] quinolizidine (IX). The substance obtained on application of methyl iodide to acetoneberberine (V) had been believed as 8-acetonyl-13-methyl-dihydroberberine hydroiodide (VI) but it was proved to be 13-methyl-2, 3-methylenedioxy-9, 10-dimethoxydibenzo [a]-5, 6-dihydroacridizinium iodide (VIII) from its analytical values and from infrared and ultraviolet spectra. The same examinations were made on the reaction products obtained from application of ethyl iodide and propyl iodide to (V). Reduction of (VIII) with sodium borohydride gives (VII) but the same reduction of 13-ethyl-2, 3-methylenedioxy-9, 10-dimethoxydibenzo[a]5, 6-dihydroacridizinium iodide (X) afforded (IX) or the dihydro compound (XII) according to reaction conditions. Reduction of (VIII) and (X) with lithium aluminium hydride in tetrahydrofuran afforded the corresponding dihydro compounds (XI and XII).

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