Synthesis, Characterization and Biological Evaulation of Some Newer Series of Quinazolone.

The amino acids of Leucine, alanine, phenylalanine and glycine at third position of the ring. Anthranilic acid was treated with chloracetyl chloride and obtained N-chloro acetyl anthranilic acid. To synthesize amino acid incorporated quinazolones, the N-chloroacetyl anthranilic acid was treated with hydrazine hydrate and derived 3-amino-2-chloromethyl quinazolin-4(3H)-one. Then this intermediate was coupled with protected amino acids, using EDC as coupling agent. Finally the BOC was deprotected to have 2-chloromethyl-3-amino acid substituted quinazolin-4(3H)- ones. Five derivatives of quinazolones were synthesize by incorporating the heterocyclic moieties of substituted Indole, Benzthiazole and Pyridine at third position of the ring. Anthranilic acid was treated with chloroacetyl chloride and obtained N-chloro acetyl anthranilic acid. To synthesize heterocyclic incorporated quinazolones, N-Chloroacetyl anthranilic acid was refluxed separately with 2-amino benzthiazole, 2- amino benzimidazole, 2-amino 5-nitro phenyl benzimidazole, 2-amino 5-nitro pyridine and 2-amino 5-bromo pyridine and resulting 2-chloromethyl-3-heterocycle substituted quinazolin-4(3H)-one. The completion of the reaction was checked by TLC. The chloroform and petroleum ether mixture was used for the purification of the amino acid derivatives of quinazolinones and the heterocylic derivatives of quinazolinones was washed thoroughly with boiling water and recrystallized from acetone: ethanol mixture (1:1). The structures of the synthesize compounds were confirmed with IR, 1H NMR and Mass spectroscopy. The synthesize compounds were tested for their analgesic activity by Eddy’s hot plate method where the source of pain is heat and the results of the compounds were compared with the standard drug pentazocine. One-way ANOVA followed by Bonferroni test was applied to the results to find the results are statistically or not in the used population. The synthesize compounds were screened for their antimicrobial activity for the gram positive, gram negative and fungal organism by disc diffusion method and the inhibition of microorganism were compared with the standard drugs ciprofloxacin and ketoconazole respectively. The compounds QAPA, QIBM shown moderate analgesic activity. The compounds QAL, QAA, QBEN, QNIBM and QPIN were shown significant activity against the organism used for the study. The two different set of quinazolones containing amino acids and heterocycles separately were synthesize and evaluated. The analgesic and antimicrobial activities are not very significant for one set of compounds than the other. Though all the compounds shown biological action it is better to incorporate the dipeptides and other heterocycles. For the amino acid series the rationale cannot be drawn for the different amino acids used, since the aliphatic amino acid leucine and alanine activity is equal to aromatic amino acid phenyl alanine. There is no distinct difference in the biological action upon increasing the hydrophobicity through increasing number of carbons. May be the di or tripeptide incorporation at the 3rd position can give an idea about whether the amino acid/peptides incorporation in the quinazolones may overtake the heterocycles or not. For heterocyclic incorporate series, among the Benzimidazole and Benzthiazole and pyridine used, the nitro group substituted compounds are active than others. May be the electron withdrawing group are required to enhance the biological action of the quinazolones