Synthesis and antimicrobial activity of new 2-[p-substituted-benzyl]-5-[substituted-carbonylamino]benzoxazoles.

A series of 23 new 2-[p-substituted-benzyl]-5-[p-substituted-phenyl/benzyl-carbonylamino]benzoxazole derivatives has been synthesized by reacting 5-amino-2-[p-substituted-benzyl]benzoxazoles with the appropriate carboxylic acid chlorides. The structures of the synthesized compounds were confirmed by IR and (1)H-NMR spectral data. Antimicrobial activities of the compounds were investigated using the twofold serial dilution technique against two gram-positive and two gram-negative bacteria and three Candida species in comparison with standard drugs.

Synthesis and structure-activity relationships of new antimicrobial active multisubstituted benzazole derivatives.

A series of multisubstituted benzoxazoles, benzimidazoles, and benzothiazoles (5-7) as non-nucleoside fused isosteric heterocyclic compounds was synthesized and tested for their antibacterial activities against various Gram-positive and Gram-negative bacteria and antifungal activity against the fungus Candida albicans. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity against the tested microorganisms at MIC values between 100 and 3.12 microg/ml.

The NH---FC dipole orientation effect for pendant exocyclic CH(2)F.

[structure: see text] DFT and MMFF force field calculations for 2 (R = H) predict that two conformers dominate in water (>/=95%) and both sustain a geometry in which the C-F and H-N dipoles align oppositely in a near-planar arrangement. The (1)H NMR spectra (D(2)O and DMSO-d(6)) and X-ray structure for 2 (R = SO(2)NHEt) confirm the predictions in all essentials. A novel single-conformer system is proposed.