Synthesis, Spectroscopic Properties and Antioxidant Activity of Bis-Hydrazones and Schiff's bases Derived from Terephthalic Dihydrazide.

A series of novel Schiff base containing bis-1,2,4-triazole and bis-hydrazone derived from terephthalic dihydrazide was synthesized. All the newly synthesized compounds were characterized by (1)H, (13)C NMR, mass spectra, FTIR and elemental analysis. UV-vis spectra and fluorescent spectra of the compounds were recorded. The effect of substituent such as electron withdrawing and electron donating groups on the fluorescent spectra was studied. Also, the comparative discussion on fluorescent spectra of Schiff's base and hydrazones has been described. The antioxidant activity of the compounds revealed that compound 5c and 5f are the most potent compounds in this series.

5-[(2-Methyl-4-nitro-1H-imidazol-1-yl)meth-yl]-1,3,4-thia-diazol-2-amine.

In the title compound, C7H8N6O2S, the dihedral angle between the imidazole and thia-diazole rings is 70.86 (15)°. In the crystal, mol-ecules are linked into [10-1] chains by N-H⋯N hydrogen bonds, which incorporate centrosymmetric R 2 (2)(8) and R 2 (2)(18) loops. The chains are linked by C-H⋯O and C-H⋯N inter-actions, generating a three-dimensional network. Very weak π-π stacking [centroid-centroid distance = 3.901 (17) Å] is also observed.

Antifungal macrodiolide from Streptomyces sp.

Aerobic fermentation cultures of Streptomyces sp. produced an antifungal macrodiolide. This new antibiotic consists of two units of homononactic acid linked to form a cyclic diester. An unknown polypeptide was also isolated in trace quantities. The antibiotic with polypeptide complex showed high levels of antifungal activity compared with that of the macrodiolide alone. The macrodiolide also showed a stimulatory effect on some species of fungi. The production, purification, and characterization of these compounds are reported.