Ethyl chlorobenzoates, hydrolysis

Obtained by reaction of p-chlorobenzo-nitrile with resorcinol in the presence of zinc chloride and hydrochloric acid in ethyl ether (Hoesch reaction) in ice during 24 h and hydrolysis of 4 -chloro-2, 4-dihydroxybenzophenone imide hydrochloride so formed (72%) with boiling water for 30 min (46%) [1253], (39%) [1256],... 

By using only half the amount of NasS and lower temperatures, the thioether intermediate 14 was obtained as the major product. Unreacted starting material was removed by column chromatography, and since the thianthrene bisamides were present in only small amounts, recrystallization from ethyl acetate allowed isolation of bisamide 14. No evidence of the 3,4 - or 3,3 -thioether isomers being formed was found. Base hydrolysis of 14 followed by recrystallization gave 4,4 -thiobis[3-chlorobenzoic acid] 15. For comparison, 4,4 -thiobis[benzoic acid] 16 was synthesized in a sin ar fashion and its NMR and FTIR spectra obtained. 

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