77 リコリン関連化合物の合成研究

概要

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(±)-α-(16) and (±)-γ-Lycorane (11) and several derivatives of (16) were synthesized by used of the reactions of a carbonyl group in cyclohexanone derivatives. The oxime of 2-oxocyclohexyl-acetic acid (4) was treated with zinc dust in AcOH to give unsaturated lactams (6),(7),(8). The unsaturated lactam (7) and (8) was converted to (11), and (16), respectively. The reaction of (4) with benzylamine in boiling o-xylene gave N-benzyl unsaturated lactam (14), which was converted to (16) (6.3% from 4). (±)-α-Lycorane-3,5-dione (30) was prepared through a cyclohexanone carboxylic acid (18) obtained by annelation reaction of aryl pyruvic acid (17) with methyl vinyl ketone. This compound (30) was subjected to the reductive amination followed by the Cope elimination reaction to give α-Δ^2-lycorene-5-one (32). Reduction and successive oxidation of the compound (32) gave α-Δ^2-lycorene-7-one (34), coversion of which to (±)-lycorine had been accomplished by K.Torssell et al. In the synthesis of 2β-phenylseleno compound (35), the reaction of (32) with PhSeOAc gave unexpectedly as a major product 3β-phenylseleno compound (36), whose structure was conformed on the base of its nmr spectrum, chemical reactions and X-ray analysis. On the other hand, the treatment in acid of (30) with PhSeCl gave 2-phenylseleno-α-lycorane-3,5-dione (46) (40%), whose oxidation afforded enone (47) and alcohol (48).
天然有機化合物討論会の論文
1979-09-20