Reaction of acyl halides with hydrogen sulfide and its derivatives

Reaction of acyl halides with hydrogen sulfide and its derivatives 

Thioacetic333 and thiobenzoic acid 333,334 In a 1-1 flask fitted with a stirrer and reflux condenser, anhydrous pyridine (200 ml) is saturated by a stream of hydrogen sulfide that has been washed by iodine solution and dried through calcium chloride. It is then treated with acetyl chloride (40 g) with stirring and cooling to below 15° for 2-3 h alternatively, benzoyl chloride (40 g) is similarly added at 5°. Thereafter the mixture is acidified with the calculated amount of 5N-sulfuric acid and extracted with ether. The extract is dried over sodium sulfate and fractionated in a stream of nitrogen, giving thioacetic, b.p. 87.5-88°, or thiobenzoic acid, b.p. 85-87°/10 mm, in 60-65 % yield. 

S-Esters of thiocarboxylic acids are obtained on acylation of thiols this reaction, which is often very smooth even in the absence of a base,335 is generally carried out by the Schotten-Baumann technique336,337 or in the presence of pyridine.338 

When shaken with benzoyl chloride and an excess of sodium hydroxide solution, 1,5-pentanedithiol gives an almost quantitative yield of S jS-pentamethylene bis(thiobenzoate), m.p. 45° (after recrystallization from ethanol).336 

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