Synthesis of 3-Substituted Pyrazole Derivatives by Mixed Anhydride Method and Study of Their Antibacterial Activities

Abstract

A convenient synthesis of 3-substituted pyrazole derivatives by a mixed anhydride method using i-butylchloroformate and N-methylmorpholine at −20 °C in tetrahydrofuran and study of in vitro antibacterial activities of the prepared compounds against Staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa, and Proteus valguris by agar-diffusion method were carried out. The results suggested that the products 4a, 4b, and 4c exhibited moderate to feeble inhibition against all test bacteria at greater concentration but 4d was best against Staphylococcus epidermidis (22 mm) and worst against Pseudomonas aeruginosa (16 mm) at the greatest concentration (2.5 mg/ml), and the activities decreased with decrease in concentration.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]

GRAPHICAL ABSTRACT

Keywords:

• Acid anhydride
• antibacterial activity
• pyrazole

ACKNOWLEDGMENTS

The authors thank the University Grants Commission, Funding for Infrastructure in Science and Technology, Department of Science and Technology, for providing infrastructural facility, Central Drug Research Institute (CDRI) Lucknow for antibacterial study, and Sophisticated Analytical Instrument Facility (SAIF), Punjab University, for providing NMR spectral data.

Notes

^a The screening organisms. Gram-positive bacteria: Staphylococcus epidermidis (Se), Bacillus subtilis (Bs). Gram-negative bacteria: Pseudomonas aeruginosa (Pa), Proteus valguris (Pv).