The use of 4-(3,4-dichlorophenyl)-4-oxo-2-(4-antipyrinyl)-butanoic acid in the preparation of some new heterocyclic compounds with expected biological activity

Reaction of 4-oxo-4-(3,4-dichlorophenyl)-2-butenoic acid (1) with antipyrin (2) gave the corresponding butanoic acid 3. Reaction of 3 with hydrazines gave the pyridazinone derivatives 5a,b. Compounds 5a,b were used to prepare the corresponding dithio derivatives. Reaction of 5a with POCl3 unexpectedly gave the chloropyridazine derivative 7, which is used to prepare the corresponding thio derivative. The hitherto unknown reactions of this chloro derivative with 2-amino-3-carbethoxy-4,5-dimethylthiophene and 2-amino-3-carbethoxy tetrahydrobenzothiophene have now been described. The behaviour of the chloro derivative toward hydrazine hydrate, sodium azide and anthranilic acid was also studied. Some of the new compounds showed antimicrobial and antifungal activities.