abstract |
Compounds of the general formula <FORM:1098805/C2/1> (wherein R1 represents a halogen atom or a C1- 7 alkyl or alkoxy group, R2 represents a phenyl or halophenyl group and the broken line denotes an optional substituent) are prepared by (a) heating a compound of the formula <FORM:1098805/C2/2> or (b) treating a compound of the formula <FORM:1098805/C2/3> with a suitable oxidizing system. |