Synthesis and Antimicrobial Activity of Some New 1,3-Diphenylpyrazoles Bearing Pyrimidine, Pyrimidinethione, Thiazolopyrimidine, Triazolopyrimidine, Thio-and Alkylthiotriazolop-Yrimidinone Moieties at the 4-Position

Abstract

1,3-diphenyl-1H-pyrazole-4-carboxaldehyde (1) reacted with ethyl cyanoacetate and thiourea to give the pyrimidinethione derivative 2. The reaction of 2 with some alkylating agents gave the corresponding thioethers 3a–e and 7. Thione 2 was cyclized to 5 and 6 upon a reaction with chloroacetic acid and with benzaldehyde, respectively. Thioether 3c was cyclized to 4 upon boiling with sodium acetate in ethanol, and 7 was cyclized to 8 upon boiling in an acetic anhydride-pyridine mixture. The hydrazino derivative 9 was prepared either by boiling 2 and/or 3a with hydrazine. The reaction of 9 with nitrous acid, acetylacetone, triethyl orthoformate, acetic anhydride, and carbon disulfide gave 10–14. The alkylation of 14 with ethyl iodide, phenacyl bromide, and ethyl chloroacetate afforded the alkythiotriazolo pyrimidinone derivatives 15a–c. The dialkyl derivative 16 was produced upon the treatment of 2 with two equivalents of ethyl iodide. Boiling 16 with hydrazine afforded the hydrazino 17. The reaction of 17 with nitrous acid, carbon disulfide, ethyl cyanoacetate, ethyl acetoacetae, and phenacyl bromide gave 18–22, respectively. Some of the newly obtained compounds were tested for their antibacterial and antifungal activities.

Keywords:

• 1,3-diphenylpyrazole
• pyrimidine
• pyrimidinethione
• thiazolopyrimidine
• thio-and alkylthiotriazolpyrimidinone
• triazolopyrimidine

Notes

**No inhibition zone =—.

*This antibacterial and antifungal screening has been done in the Mycological Center, Faculty of Science, Assiut University, Egypt.