Abstract: The invention relates to a process for the preparation of 4-(4′-chlorobiphenyl-4-yl)-4-keto-2-methylenebutyric acid of the formula (I) by Friedel-Crafts acylation of 4-chlorbiphenly with itaconic anhydride, which comprises carrying out the Friedel-Crafts acylation in aromatic solvents at a temperature from −20 to +80° C.

Abstract: The present invention relates to a process for the preparation of 3-acetoxy-2-methylbenzoyl chloride by reacting an alkali metal salt of 3-aminonaph-thalene-1,5-disulfonic acid with alkali metal hydroxide and water in the weight ratio 1:(1 to 1.6):(1 to 1.6) at 220 to 320.degree. C. to give the dialkali metal salt of the 3-hydroxy-2-methylbenzoic acid, separating off insoluble constituents from the reaction mixture, then adjusting the reaction mixture to a pH of 11.5 to 13.5 by addition of acid and reacting with acetic anhydride at -5 to +25.degree. C., precipitating the 3-acetoxy-2-methylbenzoic acid by addition of acid, separating off the 3-acetoxy-2-methylbenzoic acid and reacting it with an inorganic acid chloride to give 3-acetoxy-2-methylbenzoyl chloride.

Abstract: The invention relates to a process for the preparation of 3-hydroxy-2-methylbenzoic acid and 3-acetoxy-2-methylbenzoic acid, which comprises reacting 3-chloro-2-methylphenol (3) with benzyl chloride to give 2-benzyloxy-6-chlorotoluene (4) subjecting this to a Grignard reaction with magnesium to give (3-benzyloxy-2-methylphenyl)magnesium chloride (5) reacting this with CO.sub.2 to give 3-benzyloxy-2-methylbenzoic acid (6) hydrogenating this or its alkali metal salts in the presence of a hydrogenation catalyst to give 3-hydroxy-2-methylbenzoic acid (2) and optionally acetylating this to give 3-acetoxy-2-methylbenzoic acid.

Abstract: The invention relates to a process for the preparation of quinazoline-2,4-diones of the formula (I) ##STR1## in which R.sup.1 is (C.sub.1 -C.sub.12)alkyl, (C.sub.3 -C.sub.8)cycloalkyl or (C.sub.7 -C.sub.10)aralkyl, it being possible for the aryl group to be substituted by one or more halogen atoms, andR.sup.2, R.sup.3, R.sup.4 and R.sup.5, independently of one another, are halogen, alkyl, alkoxy or hydrogen, which comprises reacting anthranilic acid esters of the formula (II) ##STR2## in which R is (C.sub.1 -C.sub.10)alkyl and R.sup.2 to R.sup.5 are as defined above, with isocyanates R.sup.1 -.dbd.C.dbd.O in an aprotic reaction medium to give carbamoylanthranilic acid esters of the formula (III) ##STR3## in which R, R.sup.1 to R.sup.5 are as defined above, and cyclizing these products in the presence of alkali metal alcoholates, alkali metal amides, alkali metal hydrides, alkaline earth metal alcoholates, alkaline earth metal amides, alkaline earth metal hydrides or tetraalkylammonium hydroxides.

Abstract: A process for the preparation of quinazoline-2,4-diones of the formula (I) ##STR1## in which R.sup.1 is aryl and R.sub.2, R.sup.3, R.sup.4, and R.sup.5 independently of one another are halogen, alkyl, alkoxy or hydrogen, by reacting anthranilic acid esters of the formula (II) ##STR2## in an aprotic reaction medium with aryl isocyanates R.sup.1 --N.dbd.C.dbd.O to give N-arylcarbamoyl-anthranilic acid esters of the formula (III) ##STR3## and cyclizing these in the presence of a base selected from the group of alkali metal or alkaline earth metal alkoxides, amides, hydrides or tetraalkylammonium hydroxides.