Isopropanol → 1,4-Dihydro-2,6-dimethyl-5-[(2-methoxyethyl)methylsulfamoyl]-4-(3-nitrophenyl)nicotinic acid 2-propoxyethyl ester

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Reaction Steps

A solution of 3.42 g (0.01 mol) of α-acetyl-N-(2- -methoxyethyl)-N-methyl-3-nitrostyrenesulfonamide and 1.87 g (0.01 mol) of 3-aminocrotonic acid 2-propoxyethyl ester in 15 ml of isopropanol is heated to reflux for 2 hours, thereupon treated with 1.0 g of Amberlyst® 15 as the catalyst and then heated to reflux for an additional 30 minutes. After concentration under reduced pressure 0 the oily residue is dissolved in methylene chloride, the catalyst remaining behind is removed by filtration under suction, and the filtrate is washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated to dryness. The residual oil is chromatographed on 300 g of silica gel with methylene chloride/ethyl acetate (4:1) as the elution agent. The uniform fractions yield an oil which crystallizes upon trituration and leaving to stand under hexane. After recrystallization from ether, there are obtained 2.4 g (47%) of 1,4-dihydro-2 6-dimethyl-5-[(2-methoxyethyl)methylsulfamoyl]-4-(3-nitrophenyl)nicotinic acid 2-propoxyethyl ester. m.p. 67°-70°, as an almost colorless crystalline powder.

Provenance & Evidence