4-Toluenesulfonyl chloride → N-methyl-6-nitro-2,2-dimethyl-2H-1-benzopyran-4-carboxamide

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Reaction Steps

A mixture of 0.42 g of N-methyl-6-nitro-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-carbothioamide, 0.58 g of p-toluenesulfonyl chloride, and 30 ml of pyridine was heated under reflux for 3 hours. The reaction mixture was concentrated, and 2N hydrochloric acid was added to the residue. The mixture was extracted with dichloromethane, and the extract was dried over magnesium sulfate. The residue was purified by silica gel column chromatography (CH2Cl2) and then recrystalllzed from ethyl acetate to obtain 0.25 g of N-methyl-6-nitro-2,2-dimethyl-2H-1-benzopyran-4-carboxamide represented by formula shown below.

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