Palladium-Catalyzed Oxidative Three-Component Coupling of Anthranilamides with Isocyanides and Arylboronic Acids: Access to 2,3-Disubstituted Quinazolinones

Quinazolinones as Potential Anticancer Agents: Synthesis and Action Mechanisms

Quinazolinones, essential quinazoline derivatives, exhibit diverse biological activities with applications in pharmaceuticals and insecticides. Some derivatives have already been developed as commercial drugs. Given the rising cancer incidence, there is a critical need for new anticancer agents, and quinazolinones show promising potential in this domain. The present review focuses on novel advances in the synthesis of these important scaffolds and other medicinal aspects involving drug design, the structure-activity relationship, and action mechanisms of quinazoline and quinazolinone derivatives, to help in the development of new quinazoline and quinazolinone derivatives.

A vitamin C-based natural deep eutectic solvent for the synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives

Efficient and green protocols were reported to synthesize 2,3-dihydroquinazolin-4(1H)-one derivatives in natural deep eutectic solvent (NADES). NADES was prepared from ascorbic acid (AA) and choline chloride (ChCl) with reduced or null toxicity, biocompatibility, and low cost. The ChCl/AA NADES was successfully used in the synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives via the condensation reaction of aldehydes with 2-aminobenzamide and the three-component reactions of aldehydes, isatoic anhydrides and ammonium salts under solvent-free conditions. The scope of this method was evaluated by employing various aromatic, heterocyclic, and aliphatic aldehydes. The desired products were achieved in 85-97 % yield in a short reaction time. Also, the deep eutectic solvent ChCl/AA showed good recyclability and reusability.

Skeletal Editing through Molecular Recombination of 2H-Indazoles to Azo-Linked-Quinazolinones

A new protocol by the combinatory use of two equivalent of indazoles starting material with one being the carbon source via its C3-reactivity and the other, the coupling partner has been developed for the selectfluor-mediated single atom skeletal editing of 2H-indazoles. The azo-linked-2,3-disubstituted quinazolin-4-one derivatives were obtained through a carbon atom insertion between the two nitrogens of the indazole ring and simultaneous oxidation at C3 position of both indazole moieties. Mechanistic investigations reveal that the amidic carbonyl oxygen of the product is derived from water and the reaction proceeds through in-situ generated N-centred indazolone radical intermediate.

2-Substituted quinazolines: Partial agonistic and antagonistic ligands of the constitutive androstane receptor (CAR)

Following the discovery of 2-(3-methoxyphenyl)-3,4-dihydroquinazoline-4-one and 2-(3-methoxyphenyl)quinazoline-4-thione as potent, but non-specific activators of the human Constitutive Androstane Receptor (CAR, NR1I3), a series of quinazolinones substituted at the C2 phenyl ring was prepared to examine their ability to selectively modulate human CAR activity. Employing cellular and in vitro TR-FRET assays with wild-type CAR or its variant 3 (CAR3) ligand binding domains (LBD), several novel partial human CAR agonists and antagonists were identified. 2-(3-Methylphenyl) quinazolinone derivatives 7d and 8d acted as partial agonists with the recombinant CAR LBD, the former in nanomolar units (EC50 = 0.055 μM and 10.6 μM, respectively). Moreover, 7d did not activate PXR, and did not show any signs of cytotoxicity. On the other hand, 2-(4-bromophenyl)quinazoline-4-thione 7l possessed significant CAR antagonistic activity, although the compound displayed no agonistic or inverse agonistic activities. A compound possessing purely antagonistic effect was thus identified for the first time. These and related compounds may serve as a remedy in xenobiotic intoxication or, conversely, in suppression of undesirable hepatic CAR activation.

α-Keto Acids as Triggers and Partners for the Synthesis of Quinazolinones, Quinoxalinones, Benzooxazinones, and Benzothiazoles in Water

A general and efficient method for the synthesis of quinazolinones, quinoxalinones, benzooxazinones, and benzothiazoles from the reactions of α-keto acids with 2-aminobenzamides, benzene-1,2-diamines, 2-aminophenols, and 2-aminobenzenethiols, respectively, is described. The reactions were conducted under catalyst-free conditions, using water as the sole solvent with no additive required, and successfully applied to the synthesis of sildenafil. More importantly, these reactions can be conducted on a mass scale, and the products can be easily purified through filtration and washing with ethanol (or crystallized).

One-Pot Synthesis of N-Imidoyl-(1 H)-indoles via Palladium-Catalyzed Oxidative Insertion Domino Reaction with Isocyanide and Arylboronic Acid

Efficient one-pot synthesis of N-imidoyl-(1 H)-indoles has been described, which is achieved by the palladium-catalyzed oxidative insertion of 2-(phenylethynyl)aniline, arylboronic acid, and isonitrile. This method provides a new way to synthesize N-imidoyl-(1 H)-indoles, which has a wide substrate scope, good functional group tolerance, and mild reaction condition.

Copper-Catalyzed Oxidative Multicomponent Annulation Reaction for Direct Synthesis of Quinazolinones via an Imine-Protection Strategy

Via an imine-protection strategy, we herein present an unprecedented copper-catalyzed oxidative multicomponent annulation reaction for direct synthesis of quinazolinones. The construction of various products is achieved via formation of three C-N and one C-C bonds in conjunction with the benzylic functionalization. The merits of easily available feedstocks, naturally abundant catalyst, good functional group and substrate compatibility, and release of H₂O as the byproduct make the developed chemistry a practical way to access quinazolinones.

Quinazolinone Synthesis through Base-Promoted SNAr Reaction of ortho-Fluorobenzamides with Amides Followed by Cyclization

A transition-metal-free synthesis of quinazolin-4-ones by Cs2CO3-promoted SNAr reaction of ortho-fluorobenzamides with amides followed by cyclization in dimethyl sulfoxide has been developed. The present procedure can provide efficient synthetic methods for the formation of both 2-substituted and 2,3-disubstituted quinazolin-4-one rings depending on the use of easily available starting materials and an efficient, one-pot protocol for the synthesis of the marketed drug product of methaqualone.

Quinazolin-4(3H)-ones and 5,6-Dihydropyrimidin-4(3H)-ones from β-Aminoamides and Orthoesters

Quinazolin-4(3H)-ones have been prepared in one step from 2-aminobenzamides and orthoesters in the presence of acetic acid. Simple 2-aminobenzamides were easily converted to the heterocycles by refluxing in absolute ethanol with 1.5 equivalents of the orthoester and 2 equivalents of acetic acid for 12–24 h. Ring-substituted and hindered 2-aminobenzamides as well as cases incorporating an additional basic nitrogen required pressure tube conditions with 3 equivalents each of the orthoester and acetic acid in ethanol at 110 °C for 12–72 h. The reaction was tolerant towards functionality on the benzamide and a range of structures was accessible. Workup involved removal of the solvent under vacuum and either recrystallization from ethanol or trituration with ether-pentane. Several 5,6-dihydropyrimidin-4(3H)-ones were also prepared from 3-amino-2,2-dimethylpropionamide. All products were characterized by melting point, FT-IR, ¹H-NMR, ¹³C-NMR, and HRMS.