3-メチル-3-ブテニル=アセタートを原料とするジヒドロタゲトン, メントン及び関連化合物の合成
1984 年 33 巻 4 号 p. 233-236
詳細
1984 年 33 巻 4 号 p. 233-236
This paper describes the synthesis of dihydrotagetone (3), 4-methyl-6- (2-methylpropyl) -3, 4-dihydro-2 H-pyran (4), dihydrorose oxide (5), menthone (8), and isomenthone (9) from readily available 3-methyl-3-butenyl acetate (1). The synthetic route is shown in Scheme-1. The pyrolysis reaction of 3, 7-dimethyl-5-oxooctyl acetate (2), obtained by a radical addition of 3-methylbutanal with (1), gave (3) in a 52% yield. This reaction was carried out by passing compound (2) through an electrically heated Pyrex tube packed with ceramic beads at 400420°C. On using a silica-calcia or silica-alumina cat., (4) was obtained from (2) in a 4962% yield.
Compounds (8) and (9) were prepared from 8-bromo-2, 6-dimethyl-4-octanone (7) by an intramolecular alkylation reaction, in resulting a 60% yield. The alkylation reaction was carried out with powdered potassium hydroxide in the presence of a crown ether as a catalyst in benzene.
