2-(acetylsulfanylmethyl)butanedioic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 582 g (2.85 mol) of acetylthiomethylbutanedioic acid (VII) are added, under nitrogen and while cooling with ice, to a solution of 570 g (14.25 mol) of NaOH in 3 litres of water (exothermic reaction). After 15 hours' stirring at room temperature, the reaction mixture is acidified to pH 1 with concentrated hydrochloric acid and extraction is carried out with ether. The combined organic phases are dried over sodium sulfate and concentrated to dryness, and the crystalline residue is washed with 200 ml of cold dichloromethane. There are obtained 385 g of crystals having a melting point of 107°-108.5° C. the reaction mixture is acidified to pH 1 with concentrated hydrochloric acid and extraction The combined organic phases are dried over sodium sulfate concentrated to dryness the crystalline residue is washed with 200 ml of cold dichloromethane

Conditions: temp:95.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 400 g (3.07 mol) of itaconic acid (VIII) are added in portions within a period of approximately 30 minutes to 280 g (3.68 mol) of thioacetic acid, with simultaneous heating of the heating bath to 95° C. After 2.5 hours' stirring at 90°-100° C., the reaction mixture is cooled to room temperature and diluted with 300 ml of diisopropyl ether (DIPE), whereupon the product crystallises out within a period of approximately 12 hours. There are obtained 582 g of crystals having a melting point of 89°-91° C. the reaction mixture is cooled to room temperature crystallises out within a period of approximately 12 hours

Conditions: temp:95.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 400 g (3.07 mol) of itaconic acid (VIII) are added in portions within a period of approximately 30 minutes to 280 g (3.68 mol) of thioacetic acid, with simultaneous heating of the heating bath to 95° C. After 2.5 hours' stirring at 90°-100° C., the reaction mixture is cooled to room temperature and diluted with 300 ml of diisopropyl ether (DIPE), whereupon the product crystallises out within a period of approximately 12 hours. There are obtained 582 g of crystals having a melting point of 89°-91° C. the reaction mixture is cooled to room temperature crystallises out within a period of approximately 12 hours