Synthesis and antimicrobial actvities of some nitrogen containing bases

Abstract

In this work twenty compounds were synthesized. The nature of the prepared compounds fall into three main categories, Mannich bases, indoles and aryldiazopyrazole derivatives. The synthetic designing of the target molecules was planned from the appropriate logical disconnections of the target molecules. The application of the disconnection approach together with the suitable reaction mechanisms were dealt with in chapter three of this thesis. The reaction course was followed by TLC and the same technique was used to confirm the purity of the prepared compounds after repeated recrystallization with appropriate solvents. The identity of the intermediate and the final compounds were elucidated with various spectroscopic techniques such as IR, UV-VIS, 1H, 13C-NMR and MS, DEPT and COSEY spectra were recorded for some compounds. The spectral data were interpretated and correlated with the structure of the prepared compounds. A wide range of antimicrobial activities against the standard bacterial organisms (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Proteus vulgaris and Pseudomonasaeruginosa) and a two standard fungal organisms namely, Speregellus niger and candida albicans in a concentration of 0.2 ml of 1 mg/5 ml in propylene glycol as a solvent was observed. Compound (XVI) (N-(2-phenylprop-1-phenylisonicotine amide was found to possess the highest activity. The detailed description of methods and preparative procedures were given in chapter two of this thesis. A direct simple Mannich reaction was employed, by which acetophenone was allowed to react with appropriate amines in the presence of paraformaldehyde to furnish Mannich bases. In a Claisen ester condensation type, acetophenone was allowed to react with ethyl acetate in presence of strong bases to form benzoyl acetone (1-phenyl-butan-1,3-dione) which on coupling with appropriate diazonium salts form the corresponding azodyes. These diazoaryl phenyl butandiones, containing the 1,3-dicarbonyl skeleton were condensed with a range of hydrazines to furnish the required 3-phenyl-5-methyl-4-diazoaryl pyrazoles.