反应详情

10.1 g (0.08 mol) of 5-methylisoxazole-4-carboxylic acid and 8.65 g (0.08 mol) of p-phenylenediamine are dissolved in 300 ml of tetrahydrofuran and 18.05 g (0.088 mol) of dicyclohexylcarbodiimide are added. After 5 hours (“h”), the deposited precipitate is filtered off with suction, the organic phase is concentrated and the product is chromatographed on silica gel by means of ethyl acetate/petroleum ether with addition of 1% glacial acetic acid and then crystallized from ethyl acetate/petroleum ether. The yield of the process was 6.8 g of acetate salt with a melting point of 123° C. to 128° C.

1. filtrationthe deposited precipitate is filtered off with suction
2. concentrationthe organic phase is concentrated
3. customthe product is chromatographed on silica gel by means of ethyl acetate/petroleum ether with addition of 1% glacial acetic acid
4. customcrystallized from ethyl acetate/petroleum ether