Synthesis, Spectroscopic Studies and Biological Activity of Novel Heterocyclic Compounds having five and seven membered Ring

Abstract

Keeping in view the potential biological activity of heterocyclic compounds some novel five and seven membered ring compounds have been prepared. They include pyrazoles, 1.5 benzodiazepines, 1, 4-diazepines, benzothiazepine derivatives and a few nucleosides. With unsymmetric pyrazoles, regioselectivity has been the focous of attention of many chemists. The cyclocon densation of hydrazine derivatives with phenolic 8-diketones lead to different regioisomers of pyrazoles under varied experimental conditions. The new phenolic pyrazole acetic acids showed antimicrobial activity and low cytotoxicity. Pyrazoles connected to triazole and thiadiazoles via-CH2- bridge were prepared via a multistep synthesis. Their antiviral activity is being studied these days. A multistep synthesis was planned to prepare chiral heterocyclic α- amino acids. The racemic pyrazolyl amino-acids were prepared in reasonably good yield. Unfortunately the last step to deacetylate the protected amino acids with enzyme Acylace to give chiral amino acids has been unsuccessful. Cyclocondensation of phenolic β-diketones with o-aminothiophenol in DMSO lead to oxidative cyclocondensation to give compounds having condensed ring system. DMSO itself was reduced to dimethysulfide. A number of phenolic 1, 4-diazepines and 1, 5- Benzodiazepine derivatives were prepared which were coupled with acetobromoglucose and galactose to give novel nucloeosides. These nucleosides showed antiviral activity. The testing of these nucleosides as anti AIDS agents is in progress. Apart from synthetic work some physio organic aspects of the newly synthesised molecules have been studied. Ring contraction of 2, 4-diphenyl-1, 5-benzodiazepines following electron ionization mass spectroscopy has been studied in detail. Moreover the conformational equilibrium of 2(o-hydroxy phenyl) 5-phenyl -3H- 1, 5-benzodiazepine using dynamic HNMR spectroscopy has also been studied and different physical parameters calculated