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Title:	Novel cyclodehydration reaction for the synthesis of benzoxazin-4-one derivatives
Authors:	Sayed Mahdi Shariat (P53943)
Supervisor:	Mohd Wahid Samsudin, Professor Dato' Dr.
Keywords:	Cyclodehydration Benzoxazin-4-one derivatives Heterocyclic compounds
Issue Date:	30-Mar-2013
Description:	Derivatives of benzoxazin-4-one are a significant category of fused heterocyclic compounds. Benzoxazin-4-one derivatives have a wide spectrum of application in medicinal chemistry and in various industries because of their interesting and individual characteristics. Optimizing previous synthetic methods or designing new routes by using more efficient and greener reactions is the challenge in the synthesis of benzoxazin-4-one derivatives. This study aimed to design a new and efficient method for the synthesis of benzoxazin-4-one derivatives under mild conditions, which can be applied to the chemical industry. Derivatives of 2,2'-[arylene-bis(carbonylimino)]dibenzoic acid were first prepared from anthranilic acid and di-acyl chlorides. The bis carbonylimino acid derivatives then undergone cyclodehydration to produce five (2,2'-arylene)bis(4H-3,1-benzoxazine-4-one) derivatives using reflux method and microwave-assisted reactions. For the traditional heating methods, cyanuric chloride was used as the cyclizing agent and toluene as the solvent. After 72 h of refluxing, 76- 81% yields were obtained. In the microwave-assisted method, the iminium cation from a mixture of cyanuric chloride and dimethylformamide was used as the cyclizing agent in dimethylformamide, which provided results within unexpectedly shorter reaction times (1 min to 2 min) with higher yield (77- 88%) compared with reflux method. In addition, a series of mono-benzoxazin-4-one derivatives (nine compounds) was synthesized in a one-pot reaction under mild condition from anthranilic acid and acyl chloride derivatives by using the iminium cation as a cyclizing agent. The reaction yields (79- 80%) were obtained after 4 h of stirring the mixture at room temperature. The synthesis of the second series of benzoxazin-4-one derivatives was repeated by using microwave-assisted reaction. After 1 min, the results were obtained in high yield (75- 88%). The structures of products and intermediates were confirmed by analyzing the spectral data from 1H-NMR, 13C-NMR, FT-IR, HRMS, UV spectroscopy, and CHN elemental analysis. The iminium cation from cyanuric chloride and dimethylformamide was an effective cyclizing agent for both microwave-assisted reaction and one-pot mild condition synthesis of benzoxazin-4-one derivatives. These methods yielded results in surprisingly shorter reaction time and higher yield compared with previous methods.,Ph.D
Pages:	209
Call Number:	QD400.S485 2013
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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