Tetrahydrofuran → HCID 11391154, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 4H-benzo[1,4]thiazin-3-one (6.06 mmol) in 30 mL of anhydrous THF at −78° C. is added freshly prepared LDA (13.9 mmol) dropwise. After the mixture is stirred at −78° C. for 30 minutes, it is warmed up to 0° C. for 30 minutes and cooled down to −78° C. again. The resulting mixture is then slowly transferred using a double-ended needle into a solution of ethyl glyoxalate (18.3 mmol, 50% in toluene) in 10 mL of anhydrous THF kept at −78° C. After the addition, the mixture is allowed to slowly warm up to 0° C. and to stir for 3 hours. 2 mL of a mixture of EtOH and water (1:1) is added to quench the reaction and the mixture is poured into a saturated aqueous solution of NH4Cl (50 mL). After the extraction with EtOAc (3×40 mL), the organic layers are combined and washed with brine and dried over MgSO4. After filtering off the drying agent, the solution is concentrated and purified by flash column chromatography (silica gel, 0˜2% EtOH/CH2Cl2) to provide the desired product hydroxy-(3-oxo-3,4-dihydro-2H-benzo[1,4]thiazin-2-yl)-acetic acid ethyl ester as a white solid. Yield: 32%. MS: (ES+): 268 [M+1].

Provenance & Evidence