| 摘要 |
PURPOSE:To obtain a steroidal compound useful as a synthetic intermediate for plant growth regulators and brassinolide analogs in good yield by ready operation, by reacting a stigmasterol as a raw material under specific condition. CONSTITUTION:A compound expressed by formula I [R1 is formula II (R2 is methyl or ethyl; asterisk mark * indicates the bonding position of R1 to the steroid nucleus)] is initially reacted with a compound expressed by the formula R3SO2X (R3 is lower alkyl, etc.; S is Cl or F) in the presence of an organic base, preferably at room temperature or below to give a compound expressed by formula III, which is then reacted with water in the presence of a base and, as necessary, a phase-transfer catalyst in a mixed solvent of an aromatic or aliphatic hydrocarbon based solvent and an inert water-miscible organic solvent. The resultant compound expressed by formula IV is subsequently oxidized with, e.g. chromium oxide (VI), to afford the aimed compound expressed by formula V. Each of the steps is carried out in aromatic or aliphatic hydrocarbon based solvent.
|
