A REGIOSPECIFIC SYNTHESIS OF 1-HETEROCYCLIC SUBSTITUTED 1,2,4-TRIAZOLES VIA ADDITION REACTION OF 1,2,4-TRIAZOLE WITH FUNCTIONALIZED CARBODIIMIDE

ABSTRACT

The reaction of 1,2,4-triazole with functionalized carbodiimide 2 or 6 under solid K₂CO₃ provide a convenient and regiospecific route to 1-(2-imidazolonyl)-1,2,4-triazole 4 or 1-(2-quinazolonyl)-1,2,4-triazole 8.     

Synthesis of quinazolinones from anthranilamides and aldehydes via metal-free aerobic oxidation in DMSO

A highly environmentally benign protocol for the synthesis of quinazolinones from anthranilamides and aldehydes via aerobic oxidation was developed in wet DMSO. This protocol is operationally simple, exhibits broad substrate scope, and does not need toxic metal catalysts and bases. In addition, the utility of this transformation was further demonstrated by converting the resulting quinazolinones into other useful products in the same-pot without their isolation.     

One pot synthesis of some new N-allyl and N-benzyl quinazolinones and their anti-inflammatory activity

The simple and more reliable one-pot synthesis of some novel compounds of allyl/Benzyl quinazolinone (4aa-4bd) with good yields from readily available derivatives of anthranilic acid and benzoyl chloride was also reported. Interestingly, as compared to Diclofenac sodium, compounds 4ac, 4ad, 4ba, 4bc and 4bd displayed remarkable anti-inflammatory activity (Scheme 1 & Table 2).     

Visible light induced tandem reactions: An efficient one pot strategy for constructing quinazolinones using in-situ formed aldehydes under photocatalyst-free and room-temperature conditions

A facile tandem route has been developed for constructing quinazolinones from various aminobenzamides and in-situ generated aldehydes. Visible light was found to play a dual role: first oxidizes the alcohol to the aldehyde and then facilitates its cyclization with o-substituted aniline. Furthermore, alcohols are perfect alternatives to aldehydes because they are greener, more available, more economical, more stable, and less toxic than aldehydes. The first reaction step continuously provides material for the second step, which effectively reduces loss through volatilization, oxidation, and polymerization of the aldehyde, while avoiding its toxicity. A variety of quinazolinones can be prepared in the presence of visible light without any additional photocatalyst. The developed synthesis protocol proceeds with the merits of mild conditions, broad substrate scope, operational simplicity, and high atom efficiency, with an eco-energy source under metal-free, photocatalyst-free, and ambient conditions.     

Novel 1,2,3,4‐Tetrahydroquinazolinones via Reaction of 2‐Amino‐N‐substituted Benzamides and Dimethyl Acetylenedicarboxylate

Reaction of 2‐amino‐N‐substituted benzamides and dimethyl acetylenedicarboxylate (DMAD) in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in H₂O at room temperature led to the formation of novel 1,2,3,4‐tetrahydroquinazolinones.     

Magnetically recyclable copper modified GO/Fe3O4 catalyst for efficient synthesis of quinazolinones

A series of bioactive quinazolinones were effectively synthesized by the condensation of halide benzamide with amino acid using magnetically recyclable GO/Fe_3O_4–CuI as catalyst. Magnetic GO/Fe_3O_4–CuI was prepared via a simple chemical method and characterized by FTIR, powder XRD, and SEM.This heterogeneous copper catalyst can be easily separated from reaction mixtures by an external permanent magnet and reused without any obvious loss in activity which shows its applicability as a reusable and promising catalyst for quinazolinones synthesis.     

One-pot synthesis of 4(3H)-quinazolinones from azides, alkynes, anilines, and carbon monoxide

A one-pot synthesis of 4(3H)-quinazolinones from terminal alkynes, sulphonyl azide, o-iodoanilines, and carbon monoxide has been developed. This cascade process includes the copper-catalyzed three-component reaction of alkyne, azide and amine, the palladium-catalyzed carbonylation, and the Lewis acid catalyzed hydrolysis of sulfonamide.     

Synthesis of aza analogues of the anticancer agent batracylin

Three series of pyrido-fused pyrimido[2,1-a]isoindol-7-ones were prepared from readily available (aminopyridinyl)(aryl)methanones by reduction followed by a Mitsunobu reaction with phthalimide and acid-catalysed cyclodehydration. This approach provides a wide variety of aza analogues of the antitumour agent batracylin.     

Lanthanum(III) nitrate hexahydrate or p-toluenesulfonic acid catalyzed one-pot synthesis of 4(3H)-quinazolinones under solvent-free conditions

The one-pot synthesis of quinazolinone derivatives from the reaction of anthranilic acid, trialkyl orthoformate and amines in the presence of lanthanum(III) nitrate hexahydrate or p-toluenesulfonic acid has been carried out. The reaction occurred in a few minutes under solvent-free conditions and in excellent yields.     

Synthesis of substituted 2-amino-4-quinazolinones via ortho-fluorobenzoyl guanidines

A novel route to 12 substituted 2-amino-4-quinazolinones is described. Starting from 2,6-difluoro-4-methoxybenzonitrile, substitution of one of the fluorine atoms either directly or indirectly with heterocycles (e.g., pyridyl, thiazolyl, pyrazolyl) followed by hydrolysis of the nitrile gave a series of o-fluorobenzoic acid derivatives. Condensation with a set of six N,N-disubstituted guanidines followed by base-promoted ring closure afforded 2-amino-4-quinazolinone derivatives.