Copper-catalyzed one-pot synthesis of 2-thioxo-2,3-dihydroquinazolin-4(1H)-ones from ortho-bromobenzamides and isothiocyanates

Copper-catalyzed tandem reaction of ortho-bromobenzamides and isothiocyanates is described, which provides an efficient and practical route for the synthesis of 2-thioxo-2,3-dihydroquinazolin-4(1H)-ones. The optimal condition involved the following parameters: CuI as precatalyst, Cs₂CO₃ as base, N,N′-dimethylethane-1,2-diamine as ligand, and toluene as solvent, with reaction temperature at 120 °C.     

KOH/DMSO: A basic suspension for transition metal-free Tandem synthesis of 2,3-dihydroquinazolin-4(1H)-ones

A novel protocol for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones from 2-aminobenzamides and aldehyde derivatives catalyzed by KOH/DMSO suspension has been developed. The present transition metal free methodology is operationally simple, scalable and varieties of 2,3-dihydroquinazolin-4(1H)-one derivatives were obtained in good to excellent yields in short reaction times.     

Synthesis of novel glycosyl-1,2,3-1H-triazolyl methyl quinazolin-4(3H)-ones and their effect on GLUT4 translocation

Cu(OTf)₂ catalyzed synthesis of propargylated 2,3-dihydroquinazolin-4(1H)-ones has been accomplished from 2-amino-N-propargyl benzamides and aromatic aldehydes under MW irradiation. Next, a series of novel glycosyl triazolyl methyl quinazolin-4(3H)-ones have been synthesized by CuAAC reaction of propargylated 2,3-dihydroquinazolin-4(1H)-ones with glycosyl azides followed by iodine mediated oxidation. In this series, six compounds showed promising to significant GLUT4 translocation activity comparable to rosiglitazone.     

Brønsted acidic ionic liquids catalyze the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives

A simple and facile method for the green synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives by direct three-component cyclo-condensation of isatoic anhydride, ammonium acetate (or primary amines), and arylaldehydes using different Brønsted acidic ionic liquids, for example 2-pyrrolidonium hydrogensulfate ([hnmp][HSO₄]), N-methyl-2-pyrrolidonium hydrogensulfate ([NMP][HSO₄]), and N-methyl-2-pyrrolidonium dihydrogenphosphate ([NMP][H₂PO₄]), as reusable catalysts under solvent-free conditions is described. In addition, reaction of anthranilamide and arylaldehydes for synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives was investigated.     

Electrochemical utilization of methanol and methanol-d4 as a C1 source to access（deuterated） 2,3-dihydroquinazolin-4（1H）-one

Herein, an electrocatalytic protocol for the synthesis of 2,3-dihydroquinazolin-4(1H)-one has been disclosed. Methanol is activated and utilized as the C1 source to cyclize with 2-aminobenzamides.This cyclization reaction proceeds conveniently(room temperature and air atmosphere) without any homogeneous metal catalysts, external oxidants, or bases. A wide variety of N,N-disubstituted 2,3-dihydroquinazolin-4(1H)-ones are obtained via this approach. Moreover, when methanol-d4is used, a deuterated ...     

Ethylenediamine diacetate-catalyzed three-component reaction for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and their spirooxindole derivatives

Ethylenediamine diacetate (EDDA)-catalyzed one-pot syntheses of biologically interesting 2,3-dihydroquinazolin-4(1H)-ones and their spirooxindole derivatives from isatoic anhydride, amines, and benzaldehydes or isatins via a three-component condensation in aqueous media have been described. This method is of great value because of high yields and ease of handling.     

Environmentally friendly synthesis of 2-aryl-2,3-dihydroquinazolin-4(1H)-ones by novel Co-CNTs as recoverable catalysts

The objective of this study is to investigate the possibility of using Co-CNTs as a green reaction medium and a catalyst for the cyclo-condensation of o-aminobenzamide with various aldehydes. This inexpensive, non-toxic, and readily available catalyst efficiently catalyzes the above condensation for the synthesis of 2-aryl-2,3-dihydroquinazolin-4(1H)-ones. Compared to the classical reaction, this is a simple, highly yielding, time saving, and environmentally friendly method.     

Tandem supramolecular synthesis of substituted 2-aryl-2,3-dihydroquinazolin-4(1H)-ones in the presence of β-cyclodextrin in water

Substituted 2-aryl-2,3-dihydroquinazolin-4(1H)-ones were prepared for the first time in water under neutral conditions by the reaction of aniline, isatoic anhydride, and aldehyde mediated by β-cyclodextrin in good yields. β-Cyclodextrin can be recovered and reused with a little loss of catalytic activity.     

Supported ceric ammonium nitrate: A highly efficient catalytic system for the synthesis of diversified 2,3-substituted 2,3-dihydroquinazolin-4(1H)-ones

A practically expeditious protocol has been developed for the cascade synthesis of 2,3-dihydroquinazolin-4(1H)-ones via the condensation of 2-aminobenzamide/2-aminobenzanilide and aromatic aldehydes using a catalytic amount of silica-supported ceric ammonium nitrate. This method affords rapid transformation at room temperature with good to excellent yields.     

Gallium(III) triflate-catalyzed one-pot selective synthesis of 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones

A series of 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones have been synthesized in good to excellent yields and high selectivity by one-pot reaction using isatoic anhydride, ammonium acetate (or amines), and aldehydes in ethanol or in DMSO under mild conditions, respectively. The reaction was efficiently promoted by 1 mol % Ga(OTf)₃ and the catalyst could be recovered easily after the reactions and reused without evident loss of reactivity.     

Amberlyst-15 mediated synthesis of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones and their crystal structure analysis

An efficient and clean method has been developed for the synthesis of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones using Amberlyst-15 as a recyclable catalyst. A variety of dihydroquinazolinones were prepared from 2-aminobenzamide and aldehydes under mild conditions in excellent yields. Further structure elaboration of one compound and the crystal structure analysis and hydrogen bonding patterns of the two compounds prepared by using this methodology is presented.     

Thiamine hydrochloride (VB1) as an efficient promoter for the one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones

A facile, efficient, and environmentally friendly procedure for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones from isatoic anhydride, aldehyde, and ammonium acetate in the presence of thiamine hydrochloride (VB₁) in EtOH is described. The protocol proves to be efficient and environmentally benign in terms of high yields, ease of recovery, and reusability of catalyst.     

CuO nanoparticles catalyzed simple and efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones under ultrasound irradiation in aqueous ethanol under ultrasound irradiation in aqueous ethanol

A CuO nanoparticle-catalyzed one-pot process has engineered for the preparation of diverse quinazolinones from the readily available isatoic anhydride, aldehydes and amine or ammonium. For amine substrates the reactions afford 2,3-dihydroquinazolin-4(1H)-ones in aqueous ethanol promoted by ultrasound irradiation. However, the ammonium substrates undergo intramolecular electron transfer and rearrangement yielding quinazolin-4(3H)-ones. The catalyst is recyclable four times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance (46 quinazolinones are synthesized and 9 of them are reported firstly), and providing moderate to excellent yield of the products under mild conditions.     

Synthesis of 2-aryl-2,3-dihydroquinazolin-4(1<Emphasis Type="Italic">H</Emphasis>)-ones using boric acid-functionalized MCM-41 as a novel heterogeneous catalyst under solvent-free condition

Ordered mesoporous silica material MCM-41 with covalently anchored boric acid groups located inside the mesochannels has been utilized as an acid catalyst for the ‘green’ synthesis of 2-aryl-2,3-dihydroquinazolin-4(1H)-one derivatives under solvent-free condition. This novel synthetic method offers advantages, such as excellent yields, simple reaction procedure, short reaction times and mild reaction conditions.     

Efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by titanium silicon oxide nanopowder in aqueous media

An efficient synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives is accomplished in aqueous media by a three-component reaction of isatoic anhydride, primary amines or ammonium acetate, and aldehydes catalyzed by titanium silicon oxide nanopowder. A variety of 2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized using this methodology in good to excellent yields. The catalyst was recovered and recycled up to four times without significant loss in the catalytic activity.     

New applications of cellulose-SO3H as a bio-supported and biodegradable catalyst for the one-pot synthesis of some three-component reactions

A bio-supported solid acid catalyst, cellulose-SO₃H, was used for three-component reactions to synthesize 2-amino-4-aryl-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitriles, spirooxindoles, 2,3-dihydroquinazolin-4(1H)-ones, 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones, α-amidoalkyl-β-naphthols, and α-carbamato-alkyl-β-naphthols derivatives under solvent-free conditions.     

Efficient synthesis of mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones using KAl(SO4)2·12H2O as a reusable catalyst in water and ethanol

KAl(SO₄)₂·12H₂O was found to catalyze efficiently a one-pot three-component cyclocondensation of isatoic anhydride and primary amines or ammonia sources such as (NH₄)₂CO₃, NH₄OAc and NH₄Cl with aromatic aldehydes under mild conditions to afford the corresponding mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones in good yields.     

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones from anthranilamide and ketones over Hβ zeolite in aqueous media*

The synthesis of 2,3-dihydroquinazolin-4(1H)-ones by cyclocondensation of anthranilamide with ketones in aqueous media using Hβ zeolite is reported. The scope of the reaction was explored by various ketones such as aromatic, aliphatic and cyclic ketones. Based on the preliminary mechanistic results, a tentative mechanism for the formation of 2,3-dihydroquinazolin-4(1H)-ones using zeolite catalyst (Hβ) is predicted. The reusability study, large-scale experiment and water as solvent showed significant benefits of this catalytic protocol in comparing to earlier methods.     

New synthetic methods for 2,3-diarylacridin-9(10H)-one and (E)-2-aryl-4-styrylfuro[3,2-c]quinoline derivatives

Two new synthetic methodologies for 2,3-diarylacridin-9(10H)-ones were developed. The first one involves the Heck reaction of (E)-3-iodo-2-styrylquinolin-4(1H)-ones with styrenes, leading to (E,E)-2,3-distyrylquinolin-4(1H)-ones, which when heated at high temperatures cyclize in two different ways. Electrocyclization and further in situ oxidation leads to 2,3-diarylacridin-9(10H)-ones, while tautomerization, cyclization by nucleophilic addition and further in situ oxidation produces (E)-2-aryl-4-styrylfuro[3,2-c]quinolines as the main compound. The second method gives only 2,3-diaryl-10-methylacridin-9(10H)-ones and involves the Heck reaction of (E)-3-iodo-1-methyl-2-styrylquinolin-4(1H)-ones and styrenes, leading to (E,E)-1-methyl-2,3-distyrylquinolin-4(1H)-ones, which when heated at high temperatures cyclize through electrocyclization and oxidation processes affording the expected compounds. The structures of all new compounds were established by extensive NMR studies.     

Two new fluorescent heterocyclic perimidines: first syntheses, crystal structure, and spectral characterization

An efficient one-pot synthesis of two new heterocyclic perimidines 4-(2,3-dihydro-1H-perimidin-2-yl)-2-methoxyphenol and 2-(quinoxalin-2-yl)-2,3-dihydro-1H-perimidine in good yields is presented. This methodology provides a simple, straightforward synthetic route to these interesting classes of heterocycles. Crystal structure, solvatochromism, and antibacterial activity of these organic compounds are discussed.