Synthesis of Benzo[b]thiophene Substituted Carbamates, Ureas, Semicarbazides, and Pyrazoles and Their Antimicrobial and Analgesic Activity

Abstract

2-Azidocarbonyl-3-chlorobenzo[b]thiophene 3 was obtained from 3-chloro-benzo[b]thiophene-2-carbonyl chloride 1 and 3-chloro-benzo[b]thiophene-2-carboxy hydrazide 2 . The compound 3 on Curtius rearrangement with various alcohols, amines, and hydrazines afforded the corresponding carbamates 4a–b , ureas 5a–j , and semicarbazides 6a–g , respectively. Compound 2 was also utilized for the synthesis of pyrazoles 7a–c by treatment with various chalcones. The structures of the newly synthesized compounds were elucidated on the basis of IR, ¹ H NMR, and mass spectral data and have been screened for antimicrobial and analgesic activities.

Keywords:

• Analgesic activity
• antimicrobial activity
• 2-azidocarbonyl-3-chlorobenzo[b]thiophene
• Curtius rearrangement

Notes

∗ P < 0.001 vs. control; student's t-test, n = 6.