Dimethyl Sulfoxide → 5-Methyl-4,5,6,7-tetrahydrothieno[3,2-c]pyridine-2-carbaldehyde

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Reaction Conditions

Reaction Steps

DMSO (1.7 ml, 24 mmol) in 5 ml CH2Cl2 was cooled to −50-60° C. Oxalyl chloride (1 ml, 11 mmol) in 20 ml DCM was then added within 5 minutes at 50° C. The mixture was kept at −50° C. for 5 minutes and then 1.67 gram (9 mmol) of (5-Methyl-4,5,6,7-tetrahydro-thieno[3,2-c]pyridin-2-yl)-methanol in 20 ml DCM was added at 50° C. and the mixture was stirred for another 15 minutes at 50° C. Triethylamine (7 ml) was then added at −50° C. and after 5 minutes the bath was removed and the mixture is naturally warmed up to 23° C. It was washed with 100 ml water and extracted with 100 ml ethyl acetate. The combined organic layers were dried over magnesium sulfate. Filter. Concentrate and flash column chromatograph using 0-15% methanol in ethyl acetate yielded 736 mg (45% yield) product.

Provenance & Evidence