75 酸化型ジケトピペラジン類の合成研究

概要

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Synthetic studies on the oxidized diketopiperazine derivatives, which contains double bond, hydroxy or alkoxy group at 3- or 3,6-position, was studied. Synthetic strategy for the syntheses of these compounds is direct alkylation or acylation at 3 (or 6) position. [I] Total synthesis of neoechinulin A 1. Protected neoechinulin A (Z-isomer) and its E-isomer were synthesized by condensation of 5 with 4. Deprotection of both isomers gave (±) -neoechinulin A 1, whose Z-configulation was rigorously established. [II] Synthetic studies on bicyclomycin 2. Stereocontrolled monoalkylation of 10a gave the monoalkyl derivative 11, which contains two methoxy groups in the same side. Similarly, condensation of 10a with PhO(CH_2)_2COCH_3 gave the monoalkylated compound 13. Treatment of 21 with Ac_2O-TFA at room temp gave the monoacetoxy derivative 22. In this reaction, the secondary methoxy group at 6 position of 21 was selectively transformed to acetoxy group which is more reactive leaving group than methoxy group. Treatment of 22 with CSA afforded bicyclo[4.2.2] compound 24. Aldol condensation of 24 at the bridge-head position with protected aldehyde 31 and deprotection afforded (±)-trimethylbicyclomycin 3.
天然有機化合物討論会の論文
1981-09-10