| 摘要 |
<p>1,209,725. Acetoacetic acids. LONZA Ltd. 3 July, 1969 [4 July, 1968], No. 33606/69. Heading C2C. Compounds of formula R 1 CH 2 .CO.C(R 2 )(R 3 ).COOH in novel crystalline form, where R 1 , R 2 and R 3 are H or R 1 is halogen, and R 2 and R 3 are each H or halogen, are prepared by converting diketene into the corresponding acetoacetic acid halide by reaction with anhydrous hydrogen halide or halogen at -10‹ to - 40‹ C. and hydrolysing the halide with a stoichiometrically equivalent quantity of water at -10‹ to - 40‹ C., the reaction being preferably carried out in an inert solvent, e.g. CCl 4 , from which the product crystallizes.</p> |
