Thionyl Chloride → 4-Amino-3-(5-methylthien-2-ylcarbonylamino)quinoline

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Reaction Steps

To a solution of 555 mg of 5-methylthiophene-2-carboxylic acid in 9 ml of anhydrous hexamethylphosphoramide and 0.9 ml of anhydrous acetonitrile is added dropwise 455 mg of thionyl chloride at -5°-0° C. under nitrogen. After stirring at the same temperature for 30 minutes, 570 mg of 3,4-diaminoquinoline is added and stirred at 0°-5° C. for 4 hours. The same work-up as described in Example 1 gives 900 mg of 4-amino-3-(5-methylthien-2-ylcarbonylamino)quinoline B4 as a white solid. It is suspended in 15 g of polyphosphate ester and heated at 125° C. with stirring for 3 hours. The mixture is diluted with ice-water and neutralized with 1N sodium hydroxide and extracted with ethyl acetate. The extract is washed with water and saturated sodium chloride, dried over magnesium sulfate, and evaporated. The residue is chromatographed on silica gel with chloroform-methanol (10:1 v/v) as eluent to give 456 mg (48%) of C4 as pale yellow crystals.

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