メチルヘプテノンを原料とするメントンの合成
1985 年 34 巻 11 号 p. 959-961
詳細
1985 年 34 巻 11 号 p. 959-961
This paper describes the synthesis of menthones (8) from methylheptenone (6-methyl-5-hepten-2-one). The synthetic route is shown in Scheme-1. The pyrolysis and thermocyclization reaction of 4-isopropyl-1-methyl-5-oxohexyl acetate (2), obtained by a radical addition reaction of 1, 5-dimethyl-4-hexenyl acetate (1) with acetaldehyde, gave (8) and isomenthone (9) each in a 28% yield. This reaction was carried out by heating compound (2) in a stainless tube at 350°C. Compounds (8) and (9) were also prepared from 6-bromo-3-isopropyl-2-heptanone (7) by an intramolecular alkylation reaction, in 64% yields. The alkylation reaction was carried out with sodium hydride in the presence of benzo-15-crown-5 as the catalyst in benzene.
