| 摘要 |
<p>A process for preparing a compound of formula (I), where R1 is optionally substituted alkyl or phenyl, R2 is COOH, and R3 and R4 are independently selected from hydrogen, halo, haloalkyl, nitro, hydroxy, alkoxy, haloalkoxy or alkoxyalkoxy; which process comprises oxidizing a compound of formula (II), where R1, R3 and R4 ate as defined in relation to formula (I) and R5 is H, halo or C1-4 alkyl with sodium hypochlorite or sodium chlorite in the presence of a catalytic amount of a ruthenium or palladium compound and a phase transfer catalyst in an organic solvent at a pH of 7-11.</p> |
