A new approach to the facile synthesis of mono- and disubstituted quinazolin-4(3H)-ones under solvent-free conditions

Urea-rich porous organic polymer as a hydrogen bond catalyst for Knoevenagel condensation reaction and synthesis of 2,3-dihydroquinazolin-4(1H)-ones

In this research, a new urea-rich porous organic polymer (urea-rich POP) as a hydrogen bond catalyst was synthesized via a solvothermal method. The physiochemical properties of the synthesized urea-rich POP were investigated by using different analyses like Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), energy-dispersive X-ray spectroscopy (EDS), elemental mapping analysis, X-ray diffraction analysis (XRD) and Brunauer-Emmett-Teller (BET) techniques. The preparation of urea-rich POP provides an efficacious platform for designing unique hydrogen bond catalytic systems. Accordingly, urea-rich POP, due to the existence of several urea moieties as hydrogen bond sites, has excellent performance as a catalyst for the Knoevenagel condensation reaction and multi-component synthesis of 2,3-dihydroquinazolin-4(1H)-ones.

Unique and outstanding catalytic behavior of a novel MOF@COF composite as an emerging and powerful catalyst in the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives

The creation of an emerging porous structure using the hybridization of UiO-66-NH2-MOF, a zirconium-based metal-organic framework (MOF), with a covalent organic framework (COF) based on terephthaldehyde and melamine (UiO-66-NH2-MOF@COF), was assessed using SEM, XRD, EDX/mapping, FT-IR, BET, and TGA analyses. Using the obtained composite as a potential recoverable heterogeneous nanocatalyst, different aldehydes were condensed with isatoic anhydride and anilines or ammonium acetate under solvent-free conditions to create derivatives of 2,3-dihydroquinazolin-4(1H)-one. Examining the catalytic capabilities of the designed UiO-66-NH2-MOF@COF to efficiently produce 2,3-dihydroquinazolin-4(1H)-ones was a standout activity. Low catalyst loading, simple set-up, outstanding yields, and catalyst recoverability are all benefits of this research.

Acid/Base-Steered Cascade Cyclization: An Efficient One-Pot Access to Diverse Isobenzofuranone and Isoindolobenzoxazinone Derivatives

We herein report the acid/base-steered two distinct reaction pathways of 2-acylbenzoic acids with isatoic anhydrides. In the presence of Na₂CO₃, the cascade process consists of the cyclization of 2-acetylbenzoic acid and nucleophilic ring-opening reaction of isatoic anhydride to furnish isobenzofuranone derivatives with high efficiency. However, p-toluenesulfonic acid can promote the product isobenzofuranones to undergo sequential intramolecular rearrangment, nucleophilic addition and cyclization reaction to produce diverse isoindolobenzoxazinones in good yields. The synthetic utility of this method was further demonstrated by the gram-scale preparation of the desired products and the facile transformations of the resulting products.

A novel powerful Choline Chloride – Thiourea /Sulfuric Acid, efficient and recyclable catalyst via microwave‐assisted for the synthesis of Quinazolin- 4(3H)–one derivatives as Antibacterial Agents in green media

Background:

Choline Chloride - Thiourea / Sulfuric Acid is a powerful and efficient green catalyst used for one-pot synthesis of quinazoline-4 (3H) -one derivatives via a reaction between various amines, acetic anhydride, and anthranilic acid under microwave irradiation and solvent-free conditions (4a-q). Microwave irradiation, which is a faster, more cost-effective, less energy-intensive, and more efficient method than conventional heating, has been used to synthesize some quinazolinone derivatives.

Introduction:

For the past ten years, one of the major subjects in synthetic organic chemistry has been green synthesis, which has used efficient and environmentally friendly methods to synthesize biological compounds. The use of catalysts has significant advantages, including ease of preparation and separation, chemical and thermal stability, and environmental friendliness due to features such as reusability, low cost, and efficient, easy workup techniques. Therefore, the mechanism is performed by a non-toxic organic catalyst that uses the least energy and chemical reactants in accordance with the principles of green chemistry and least waste.

Methods:

One-pot and sequential addition methods have been used to synthesize quinazolinone derivatives. In the sequential addition method, the reaction was started by adding acetic anhydride and anthranilic acid to the reaction vessel under microwave irradiation and continued by adding choline chloride thiourea / sulfuric acid as efficient recyclable green catalysts and the desired amine. In vitro, the well diffusion method against different pathogenic strains was used to evaluate the antimicrobial activity of quinazoline-4 (3H) -one derivatives. Pathogenic strains used were Candida albicans ATCC 10231 (yeast), Aspergillus niger ATCC 16404 (fungus), Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 (bacteria) and ATCC 6538, and Staphylococcus aureus S. epidermidis ATCC 12228. Pyrimidine-containing compounds in which the 3-hydroxyl, 2,5-Dimethoxy, 4-bromo, 4 ‐ Methoxy, and 4 ‐ chloro groups are attached to the phenyl ring of pyrimidine exhibit antimicrobial properties.

Results:

In a short reaction time, a variety of biologically active quinazolinone derivatives were synthesized with a high efficiency. According to the results, it was found that with aliphatic amines, the reaction time was shorter and the reaction efficiency was higher. Products synthesized from aromatic amines had more antibacterial properties.

Conclusion:

In this work, a variety of 2-methyl-quinazoline-4 (3H) -one derivatives (4a–q) were synthesized as potent antibacterial agents under microwave irradiation and solvent-free conditions in the presence of ChCl-thiourea / H2SO4 as an efficient, eco-friendly, and recyclable catalyst.

Thiol substrate-promoted dehydrogenative cyclization of arylmethyl thiols with ortho-substituted amines: a universal approach to heteroaromatic compounds

A thiol substrate-promoted one-pot synthesis of a library of heteroaromatic compounds was developed.

Copper-catalyzed synthesis of 2,3-disubstituted quinazolin-4(3H)-ones from benzyl-substituted anthranilamides

An efficient, practical approach to the copper-catalyzed synthesis of 2,3-disubstituted quinazolin-4(3H)-one derivatives is described. The preparation involves treatment of benzyl amines with benzyl anthranilamides in the presence of Cu(OAc)2 and tetra-n-butylammonium bromide (TBAB).

Functionalization of 3-chloroformylcoumarin to coumarin Schiff bases using reusable catalyst: an approach to molecular docking and biological studies

Recently, heterogeneous catalysts have been explored eximiously in the synthesis of heterocyclic compounds. Therefore, here we used solid-supported heterogeneous silica sulfuric acid as a catalyst for the synthesis of Schiff's base of 3-chloroformylcoumarin in view of simplified procedure, reusability and acceptable efficiency, which are required in organic synthesis. An efficient and facile methodology is preferred for synthesis of a class of chromeno-3-substituted derivatives (1a-1l) with good yields. The molecular docking results showed excellent binding interactions with the Mycobacterium tuberculosis InhA-D148G mutant (PDB: 4DQU). The same biomolecules were screened for their in vitro anti-tubercular activity against the M.tb H37Rv strain and antimicrobial studies. Physico-chemistry, toxicity prediction with IC50 value and bioactivity score were also calculated for title compounds. Most active compounds were further tested for cytotoxicity studies and exhibited low-level cytotoxicity against Vero cells. The suggested conjugates are promising lead compounds for the subsequent investigation in search of new anti-tubercular agents. All the conjugates were obtained within the range and followed the Lipinski rule of 5, indicating more 'drug-like' nature.

Synthesis of Novel Ethyl 1-aryl-3-methyl-8-oxo-1,8-dihydropyrano[2′,3′:4,5] Pyrimido[6,1-b]Quinazoline-2-carboxylate Derivatives

In this paper, a new series of ethyl 1-aryl-3-methyl-8-oxo-1,8-dihydropyrano[2′,3′:4,5]pyrimido[6,1-b]quinazoline-2-carboxylate derivatives was synthesised by the cyclisation of methyl anthranilate with ethyl 5-cyano-6-[(ethoxymethylene)amino]-2-methyl-4-aryl-4H-pyran-3-carboxylate derivatives, which were obtained from reaction of triethyl orthoformate with 6-amino-5-cyano-2-methyl-4-aryl-4H- pyran-3-carboxylate derivatives. The title compounds possessed good fluorescence properties. In addition, ethyl 5-cyano-6-[(ethoxymethylene) amino]-2-methyl-4-(p-tolyl)-4H-pyran-3-carboxylate and ethyl 3-methyl-8-oxo-1-(p-tolyl)-1,8-dihydropyrano[2′,3′:4,5]pyrimido[6,1-b] quinazoline-2-carboxylate were further determined by single crystal X-ray diffraction analysis.

Efficient and Practical One-Pot Route to Synthesise Quinazolin4(3H)-Ones Using Trifluoromethanesulfonic Anhydride and 2-Chloropyridine

An effective, novel and rapid one-pot three-component route to quinazolin-4(3H)-ones from commercially available starting materials is described. Isatoic anhydride reacts with acyl chlorides and different amines using a combination of trifluoromethanesulfonic anhydride (Tf2O) and 2-chloropyridine (2-ClPy) to produce the corresponding quinazolinone derivatives in good to excellent yields.

Convenient synthesis of 2,3-disubstituted quinazolin-4(3H)-ones and 2-styryl-3-substituted quinazolin-4(3H)-ones: applications towards the synthesis of drugs

Simple, convenient, and green synthetic protocols have been developed for the one pot synthesis of 2,3-disubstituted quinazolin-4(3H)-ones and 2-styryl-3-substituted quinazolin-4(3H)-ones under catalyst and solvent free conditions.

Sulphuric acid immobilized on silica gel (H2SO4–SiO2) as an eco-friendly catalyst for transamidation

A novel method of transamidation of carboxamides with amines using catalytic amounts of H₂SO₄–SiO₂ under solvent-free conditions has been developed. The scope of the methodology has been demonstrated with primary and secondary amines.

Oxidant- and metal-free synthesis of 4(3H)-quinazolinones from 2-amino-N-methoxybenzamides and aldehydes via acid-promoted cyclocondensation and elimination

This paper presents a novel one-pot synthesis of biologically relevant 4(3H)-quinazolinones, in the absence of oxidants or heavy-metal catalysts.

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA) as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.

Diversity-oriented synthesis of benzimidazole, benzoxazole, benzothiazole and quinazolin-4(3H)-one libraries via potassium persulfate-CuSO4-mediated oxidative coupling reactions of aldehydes in aqueous micelles

Libraries of 2-substituted-benzimidazoles, benzoxazoles, benzothiazoles as well as quinazolin-4(3H)-ones were synthesized via potassium persulfate-CuSO(4)-mediated oxidative coupling of aldehydes with o-phenylenediamines, o-aminophenols, o-aminothiophenols, and anthranilamide, respectively, in aqueous micelles. The strategy opens a way for rapid generation of libraries of small heterocycles for biological screening. The reagent is commercially available, cheap, and highly chemoselective. The yields were superior in aqueous micelles to those in organic solvents. Short reaction times, large-scale synthesis, excellent chemoselectivity, excellent yields, as well as environmental friendliness are the main advantages of this diversity-oriented synthesis.