| 摘要 |
Carboxylic acids of formula (I): RCOOH (where R is a gp. for formula R' is vinyl, 1-bromo-3,3,3-trichloropropyl, 1,3,3,3-tetrachloropropyl, 1-bromo-3,3-dichloroprop-2-enyl, 1,3,3-trichloroprop-2-enyl or 3,3,3-trichloroprop-1-enyl; R" is 2,2,2-trichloroethyl or 2,2-dichlorovinyl) are prepd. by (a) reacting an aldehyde of formula RCHO with hydroxylamino or an acid-addn. salt thereof, opt. in the presence of a base; (b) dehydrating the resulting novel oxime of formula RCH=NOH (III); and (c) hydrolysing the resulting novel nitrile of formula RCN(IV) Cpds (I) include valuable intermediates, e.g. 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropane-carboxylic acid is an intermediate for pyrethroid insecticides. |
