Synthesis of Analgesics. XIX. Antipyrine Derivatives. (6)

1) 4-Formylantipyrine (III), 4-acetylantipyrine (XVIII), and 1, 2-diphenyl-3-methyl-4-formyl-(IV) and 1, 2-diphenyl-3-methyl-4-acetyl-5-pyrazolone (XIX), when heated with sulfur in morpholine, yielded the corresponding compounds of morpholides (V, XX, VI, and XXI). These morpholides were submitted to hydrolysis with aqueous or alcoholic alkali and respectively gave 4-antipyrinecarboxlic acid (VII), 4-antipyrineacetic acid (XXII), 1, 2-diphenyl-3-methyl-5-pyrazolone-4-carboxlic acid (VIII), and 1, 2-diphenyl-3-methyl-5-pyrazolone-4-acetic acid (XXIII), each in a good yield. 2) 4-Antipyrinecarboxamide (XIII) was converted to 4-aminomethylantipyrine (XXIV) by lithium aluminum hydride. However, hydrogenation of N, N-dialkyl-4-antipyrine-carboxamides (XIV) and (XV) under similar conditions gave 4-formylantipyrine (III).