Acid‐Catalysed Cyclization of o‐Aminobenzamide with α‐Oxodithioesters: A Divergent and Regioselective Synthesis of Quinazolinones and 1, 3‐Benzothiazinones. Issue 1 (2nd January 2023)

• Record Type: Journal Article
• Authors: Kiran, Kuppalli R.; Swaroop, Toreshettahally R.; Preetham, Ramesh; Georghiou, Paris E.; Rangappa, Kanchugarakoppal S.; Sadashiva, Maralinganadoddi P.
• Is Part Of: ChemistrySelect. Volume 8:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-02
• Subjects: Quinazolinones -- Benzothiazinones -- α-Oxodithioester -- o-aminobenzamide -- Cyclisation; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202203618
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Acid catalysed cyclization of o ‐aminobenzamide and α ‐oxodithioesters in a highly regioselective fashion to give 2‐aroylquinazolin‐4(3 H )‐ones and 2‐aroyl‐4 H ‐benzo[d][1, 3]thiazin‐4‐ones by switching the reaction medium from DMF to acetic acid. Further, the generality of the stabilised protocols was tested with various functionalities. The range of yields for the quinazolinones and 1, 3‐thiazinone are 57–67 % and 70–81 %, respectively. Probable mechanisms for the formation of the two series of products are proposed from control experiments. Abstract : We have reported an acid catalysed highly regioselective cyclization of α ‐oxodithioesters and o ‐aminobenzamide to form 2‐(4‐substituted‐benzoyl) quinazolin‐4(3H)‐ones and 2‐(4‐substitutedbenzoyl)‐4H‐benzo[d][1, 3]thiazin‐4‐ones by switching the reaction medium from DMF to acetic acid. Further, optimized the reaction condition and also studied the substrate scope of the methodologies. Finally, we proposed probable mechanisms for the formation of both quinazolinone and 1, 3‐benzothiazinones by utilizing the results of the control experiments.