| abstract |
The present invention relates to a process for preparing benzophenones of the formula: (SEE FIGURE) wherein R1, R2 and R3 represent hydrogen or ethyl, being at least one ethyl, Ar is a phenyl group substituted at positions 2, 3 or 4, from one to three groups selected from chlorine, fluorine, methyl, carboxy, COOR5 and trifluoromethyl; Z is hydrogen or COR6 where R6 is C1-C4 alkyl or phenyl; with the proviso that, when R1 is ethyl and R2 and R3 are hydrogen, Ar is not 2,4- or 3,4-dichloro-phenyl, 2- or 3-chlorophenyl or 4-chlorophenyl characterized in that a compound is reacted acid of the formula A-COOX where X is hydrogen or halogen and where A is selected from the group: (SEE FIGURE) where R1, R2, R3 and Z signify the above, or the group Ar, under acylation conditions of Friedel-Grafts, in the presence of a Lewis acid, with a reagent selected from ArH Y (SEE FIGURE) in which R1, R2, R3 and Z represent the above. |