Synthesis, antimicrobial, analgesic activity, and molecular docking studies of novel 1-(5,7-dichloro-1,3-benzoxazol-2-yl)-3-phenyl-1H- pyrazole-4-carbaldehyde derivatives

Condensation of 5,7-dichloro-2-hydrazino-1,3-benzoxazole 3 with different aromatic acetophenones in methanol using catalytic amount of glacial acetic acid afforded the corresponding 1-phenylethanone(5,7-dichloro-1,3-benzoxazol-2-yl)hydrazones 5a–e in good yield. The compounds 5a–e, when subjected to Vilsmeier–Haack reaction with POCl3 in DMF yielded (5,7-dichloro-1,3-benzoxazol-2-yl)-3-phenyl-1H-pyrazole-4-carbaldehyde derivatives 6a–e. The structural assignments of the compounds 6a–e are based on their spectral data and elemental analysis. The obtained compounds were tested for antimicrobial and analgesic activities, and subjected to molecular docking studies with respect to antimicrobial activity. The compound 6b showed pronounced antimicrobial and analgesic activity and exhibited an interesting binding profile with very high receptor affinity.