p-Toluenesulfonic acid → 1,3-Dithiane-2-carboxylic acid

9.20 g (100 mmol) of glyoxalic acid monohydrate, 11.1 ml (110 mmol) of 1,3-propanedithiol and 1.72 g (10.0 mmol) of para-toluenesulphonic acid were heated in 200 ml of toluene under reflux for 3 h. The reaction mixture was cooled to RT and extracted three times with 100 ml of saturated aqueous sodium bicarbonate solution. The combined aqueous phases were washed with 200 ml of diethyl ether, acidified with aqueous hydrochloric acid (6N) and extracted four times with 200 ml of ethyl acetate. The combined organic phases were dried over magnesium sulphate and filtered, and the solvent was removed under reduced pressure. The residue was used for the next step without further purification. Yield: 8.0 g (47% of theory)

1. temperatureunder reflux for 3 h
2. extractionextracted three times with 100 ml of saturated aqueous sodium bicarbonate solution
3. washThe combined aqueous phases were washed with 200 ml of diethyl ether
4. extractionextracted four times with 200 ml of ethyl acetate
5. dry with materialThe combined organic phases were dried over magnesium sulphate
6. filtrationfiltered
7. customthe solvent was removed under reduced pressure
8. customThe residue was used for the next step without further purification

ORD record

ord-44198022921e4074961d14a1761bdab7

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09434690B2