反应详情

Puberulic acid is also obtainable by direct chemical synthesis, as disclosed by Johns et al., Jour. Chem. Soc. 1954, 198. According to this method, a solution of 3,4,6-trimethoxycycloheptatriene-caboxylic acid (an intermediate obtained by reacting diazoacetic ester and 1,2,4-trimethoxybenzene) in chloroform is reacted with a solution of bromine in carbon tetrachloride; the obtained precipitate is then heated in ethyl acetate, cooled in ice and then hydrolyzed with hydrobromic acid, obtaining stipitatic acid. Said stipitatic acid is then reacted with bromine, in order to obtain monobromostipitatic acid which is in turn reacted with potassium hydroxide to obtain the desired puberulic acid.

1. temperaturecooled in ice