| 摘要 |
PURPOSE:To produce the titled compound useful as a raw material for indole alkaloid, etc., in high yield, by adding hydrogen bromide to a 4-pentenal compound or its acetal derivative in a solvent in the presence of a diazo compound as a radical initiation agent. CONSTITUTION:A 5-bromo-1-pentanal compound of formula II (e.g. 5-bromo-2- ethylpentanal) or its acetal derivative can be produced by the addition reaction of hydrogen bromide to a 4-pentenal compound of formula I (R1 and R2 are H or alkyl (e.g. 2-ethyl-4-pentenal) or its acetal derivative in a solvent such as n-hexane, heptane, etc., in the presence of a radical initiator selected from diazo compounds such as 2,2'-azobisisobutyronitrile, etc. EFFECT:The objective compound can be produced from an easily available raw material at a low cost. USE:Synthetic raw material of tricyclic sesquiterpene, etc. |
