Studies on organosulfur compounds. XII. Syntheses and pharmacological activities of 2-heterocyclic substituted 4(3H)-quinazolinones.

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

“…as coupling partners to afford the cross-coupled products 4a-h in appreciable yields and high purity without the need for column chromatography (Scheme 3). The heterocyclic ring of the 2,3-dihydroquinazolin-4(1H)-ones has been found to undergo a different degree of unsaturation through dehydrogenation or aromatization to afford the potentially tautomeric quinazolin-4(3H)-ones or their quinazoline derivatives [28][29][30][31][32]. Quinazolin-4(3H)-ones are versatile building blocks in the synthesis of novel 2,3-disubstituted quinazolinones [28][29][30][31] and their 2,4-disubstituted quinazoline derivatives using the principles of lactam-lactim dynamic equilibrium phenomena [32].…”

“…The heterocyclic ring of the 2,3-dihydroquinazolin-4(1H)-ones has been found to undergo a different degree of unsaturation through dehydrogenation or aromatization to afford the potentially tautomeric quinazolin-4(3H)-ones or their quinazoline derivatives [28][29][30][31][32]. Quinazolin-4(3H)-ones are versatile building blocks in the synthesis of novel 2,3-disubstituted quinazolinones [28][29][30][31] and their 2,4-disubstituted quinazoline derivatives using the principles of lactam-lactim dynamic equilibrium phenomena [32]. Oxidants such as KMnO 4 [28], CuCl 2 [29], DDQ [30] and MnO 2 [31] have been employed before in stoichiometric or large excess to convert the 2,3-dihydroquinazolin-4(1H)-ones into their quinazolin-4(3H)-one derivatives.…”

“…Quinazolin-4(3H)-ones are versatile building blocks in the synthesis of novel 2,3-disubstituted quinazolinones [28][29][30][31] and their 2,4-disubstituted quinazoline derivatives using the principles of lactam-lactim dynamic equilibrium phenomena [32]. Oxidants such as KMnO 4 [28], CuCl 2 [29], DDQ [30] and MnO 2 [31] have been employed before in stoichiometric or large excess to convert the 2,3-dihydroquinazolin-4(1H)-ones into their quinazolin-4(3H)-one derivatives. In this investigation, we opted for the use of molecular iodine which has been used before as an oxidant to effect the oxidative aromatization of α,β-unsaturated cyclic compounds and the analogous 2,3-dihydroquinolin-4(1H)-ones [24].…”

Synthesis and Photophysical Property Studies of the 2,6,8-Triaryl-4-(phenylethynyl)quinazolines

“…The potentially tautomeric quinazolin-4(3H)-one moiety itself is readily accessible via dehydrogenation of the corresponding 2,3-dihydroquinazolin-4(1H)-one precursors using oxidants such as KMnO 4 [10], CuCl 2 [11], DDQ [12] and MnO 2 [13] in stoichiometric or large access. The 2-substituted quinazolin-4(3H)-ones have also been synthesized directly from anthranilamide and aldehydes using NaHSO 3 [14], DDQ [15], CuCl 2 (3 equiv.)…”

Copper-Catalyzed Domino Synthesis of Quinazolin-4(3H)-ones from (Hetero)arylmethyl Halides, Bromoacetate, and Cinnamyl Bromide

“…29 Surprisingly, heteroaryl bromide, i.e., 2-(bromomethyl)pyridine afforded 2-(2-pyridyl)quinazolin-4(3H)-one (3m) (entry 13), a compound similar to a series of bioactive natural products luotonins, 2 rutaecarpine, 3 and drug candidates. 1a Interestingly, 4-(chloromethyl)pyridine also gave the desired 2-(4-pyridyl)quinazolin-4(3H)-one (3n), whose derivative has a promising hypnotic effect, 30 but with a lower yield due to the lower reactivity of 4-(chloromethyl)pyridine (entry 14).…”