2-Aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1H)-ones as substrates for the synthesis of 2,6,8-triarylquinazolin-4-ones

• Published in: Bulletin of the Chemical Society of Ethiopia Vol. 28; no. 1; pp. 81 - 90
• Main Authors: Mphahlele, Malose J, Maluleka, Marole M, Khoza, Tebogo A
• Format: Journal Article
• Language: English
• Published: Chemical Society of Ethiopia 01.01.2014
• Subjects: 2-Amino-3; 2-Aryl-6; 3-dihydroquinazolin-4(1H)-ones; 5-dibromobenzamide; 8-dibromo-2; 8-Triaryl-2; 8-Triarylquinazolin-4(3H)-ones; Ammonium salts; Carbon tetrachloride; Reagents; Sulfonic acids; Suzuki-Miyaura cross-coupling
• ISSN: 1011-3924; 1011-3924; 1726-801X
• DOI: 10.4314/bcse.v28i1.10

Direct bromination of 2-aminobenzamide was achieved using N-bromosuccinimide in chloroform-carbon tetrachloride mixture at room temperature for 3 h to afford 2-amino-3,5-dibromobenzamide in high yield and purity. 2-Amino-3,5-dibromobenzamide was, in turn, condensed with benzaldehyde derivatives in the presence of boric acid to afford novel 2-aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1H)-ones. Suzuki-Miyaura cross-coupling of the latter with arylboronic acids yielded the corresponding 2,6,8-triaryl-2,3-dihydroquinazolin-4(1H)-ones. These triarylquinazolin-4(1H)-ones were dehydrogenated using iodine (2 equiv.) in ethanol under reflux to yield the potentially tautomeric 2,6,8-triarylquinazolin-4(3H)-ones. KEY WORDS: 2-Amino-3,5-dibromobenzamide, 2-Aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1H)-ones, Suzuki-Miyaura cross-coupling, 2,6,8-Triaryl-2,3-dihydroquinazolin-4(1H)-ones, 2,6,8-Triarylquinazolin-4(3H)ones