Dimethyl Sulfide → 2-Methyl-tetrahydrothiopyran-4-one-3-carboxylic acid

To a stirring solution of methyl cuprate in dimethylsulfide (prepared from 1.05 g copper (I) iodide/4.0 mL dimethylsulfide and 4.0 mL methyllithium/ether at −78° C.) at −78° C. was added a solution of 2,3-dihydrothiopyran-4-one-3-carboxylic acid, allyl ester (0.910 g, 4.6 mmol) in dimethylsulfide (5 mL). The resulting yellow-colored solution was stirred for 30 min. at the same temperature. The reaction mixture was quenched with a saturated solution of ammonium chloride and ammonia solution and then warmed to room temperature for and 1 h. The reaction mixture was added to ether (100 mL) and the etheral layer washed with saturated sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent was evaporated and the product purified by flash column chromatography on silica gel eluted with hexane:ether (4:1) to give 2-methyl-tetrahydrothiopyran-4-one-3-carboxylic acid, allyl ester (0.794 g) as a 7:3 mixture of enol : keto tautomers.

1. customThe reaction mixture was quenched with a saturated solution of ammonium chloride and ammonia solution
2. additionThe reaction mixture was added to ether (100 mL)
3. washthe etheral layer washed with saturated sodium chloride solution
4. dry with materialdried over anhydrous magnesium sulfate
5. customThe solvent was evaporated
6. customthe product purified by flash column chromatography on silica gel
7. washeluted with hexane:ether (4:1)

ORD record

ord-145626fa40b34eb7ab5c959a3a840d03

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06372733B1