Dept. of Pharmaceutical Chemistry
JNTUA – OTRI, Anantapur, India
Quinazolinone is a heterocyclic compound. There are two structural isomers, 2-quinazolinone and 4-quinazolinone, with the 4-isomer being the more common. Various novel classes of structurally different quinazolinones have been designed and synthesized depicting potential interventions such as antibacterial, antifungal, antiviral, anticonvulsant, CNS depressant, anti-inflammatory, antihistaminic, anticancer and so on. At present some novel quinazolinone derivatives are synthesized and characterized by IR, H1 NMR, MASS Spectral studies.
Key words: Quinazolinone, Anthranilic acid, 2-methyl 3-amino quinazoline 4(3H) one, Acetyl chloride, Chloro ethylacetate, Ethanol.
Quinazolinone has been considered as a magic moiety possessing myriad spectrum of medicinal activities. Diversity of biological response profile has attracted considerable interest of several researchers across the globe to explore this skeleton for its assorted therapeutic significance. Various novel classes of structurally different quinazolinones have been designed and synthesized depicting potential interventions such as antibacterial, antifungal, antiviral, anticonvulsant, CNS depressant, anti-inflammatory, antihistaminic, anticancer and so on. Moreover, the nucleus constitutes an integral structural component in a number of drugs currently employed in several clinical therapies.
Experimental :1. Preparation of 2-methyl 3amino quinqzolin-4(3H) one
To a solution of anthranilic acid (0.1mol) is taken in a beaker and pyridine, acetyl chloride (0.2mol) was added. The reaction mixture is stirred continuously at 60o–90o further followed by 5%of sodium bicarbonate. The solid obtained is recrystalized from ethanol and dried.
A mixture of 2-methyl-4H-benzo[d][1,3]oxazin-4-one (0.01mole) compound was taken in round bottom flask and treated with hydrazine hydrate in ethanol was refluxed for 3hrs at 60o–90o and the resulting solution was poured in to the crushed ice. A white precipitated was obtained and recrystalized with ethanol and dried.
2. Preparation of ethyl 2-(4-oxo-2-methyl quinazolin-3(4H)-yl amino) acetate
A mixture of 2-methyl 3amino quinqzolin-4(3H)-one compound (0.01mole) was taken in round bottom flask and treated with chloro ethyl acetate (0.01mole), DMA, acetone, potassium acetate, and refluxed for 6hrs and the resulting solution was poured in to crushed ice, precipitated was obtain, filtered and recrystalized with ethanol for two times and dried.
3. Preparation of 2-(4-oxo-2-methylquinazolin-3(4H)-yl-amino) aceto hydrazide
A Mixture of ethyl 2-(4-oxo-2-methyl quinazolin-3(4H)-yl-amino) acetate (0.01mole)was taken in round bottom flask and treated with hydrazine hydrate (0.01mole), in ethanol refluxed for 3hrs at 60o–90o and the resulting solution was poured in to crushed ice, precipitated was obtain, filtered and recrystalized with ethanol for two times and dried.
4. Preparation of 3-((5-phenylhydroxyl -1, 3, 4-oxadiazol-2-yl) methylamino)-2-methyl Quinazolin-4(3H)-one
A mixture of 2-(4-oxo-2-methylquinazolin-3(4H)-yl-amino) aceto hydrazide compound (0.1mol) was treated with salicylic acid in POCl3 was refluxed for 5hrs at 60o–90o and the contents were cooled and poured in to crushed ice. Then it was neutralized with NaHCO3 solution and resulting solid was filtered and recrystalized with ethanol and dried.
Results & Discussion :
The synthesized quinqzoline derivatives further studied for characterization of UV, IR, NMR and Mass. To study the structure- activity relationship and to optimize the structure 3-((5-phenylhydroxyl-1, 3, 4-oxadiazol-2-yl) methyl-amino)-2-methyl quinazolin-4(3H)-one
The IR spectrum of the compound IV was recorded on FTIR spectrometer by KBr method. The FTIR spectra shows bands at 3405.50 cm-1,3120.10cm-1 , 1593.30 cm-1, 1107.20 cm-1 and 1700.20 cm-1 corresponds to 2o amine, aromatic C-H (strech), Imine (C=N), (C-O-C) stretch and quinazolinone (C=O) repectively. These observed values are in match with the reference values.
Proton Magnetic Resonance Spectrum:
The 1HNMR spectrum was recorded on JMR spectrometer using TMS as internal standard and DMSO as solvent. The 1HNMR spectrum of compound IV shown in figure.2 and table .2 showed singlets at δ 2.35 (3H, S, CH3) which represent the methyl group and at δ 9.8 (1H, S, N-H) which represent the N-H group. It showed multiplets at δ 7.1-8.1(8H, M, Ar-H) which represent the aromatic protons.
Conclusive evidence was obtained from the mass spectrum data in fig.3 the mass spectrum showed M+ peak indicating molecular weight of the compound 349. Thus the structure of the compound is confirmed.
The synthesized quinqzolinone derivatives characterized by IR, NMR and Mass spectral studies.By this studies find the structure-activity relationship and to optimize the structure. The new synthesized quinazolinone derivative i.e., 3-((5-phenyl hyroxyl -1, 3,4-oxadiazol-2-yl) methyl amino)-2-methylquinazolin-4-(3H)-one was confirmed by physicochemical and spectral analysis.