Synthetic studies on 3-arylquinazolin-4-ones: intramolecular nucleophilic aromatic substitution reaction of 2-carboxamido-3-arylquinazolin-4-ones and its application to the synthesis of secondary aryl amines

The general synthesis and a novel intramolecular nucleophilic aromatic substitution (S_NAr) reaction of 2-carboxamido-3-arylquinazolin-4-ones, a potentially useful scaffold in the field of medicinal chemistry, are described. The synthetic utility of the S_NAr reaction as a tool for the synthesis of secondary aryl amines, including diaryl amines, is also demonstrated.     

Dehydration of 4-hydroxy-4-methyl-3-phenylamino-oxazolidin-2-ones

The dehydration of two 5,5-disubstituted 4-hydroxy-4-methyl-3-phenylaminooxazolidin-2-ones into the corresponding 4-methylene-3-phenylaminooxazolidin-2-ones has been carried out. The structure of the products was confirmed by X-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1512–1517, October, 2004.     

A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones

A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones and its derivatives using the condensation reaction of substituted 2-aminobenzamide and orthoesters is reported.     

A new one-pot neat synthesis of 1,2,4-triazol-3-ones through 4-（N,N-dimethylamino） pyridine （DMAP） catalyzed cyclocondensation of ethyl carbazate with aryl nitriles

A new one-pot neat synthesis of some 5-aryl-2,4-dihydro-3H- 1,2,4-triazol-3-ones through cyclocondensation of ethyl carbazate with aryl nitriles catalyzed by DMAP as an efficient and basic nucleophilic catalyst is described.     

Solid-phase synthesis of 1,5-substituted 2-(N-alkylamino)-imidazolidin-4-ones

The solid-phase synthesis of 1,5-substituted 2-(N-alkylamino)-imidazolidin-4-one from resin-bound amino acid is described. Using a guanidinylating reagent in solution to form the guanidine moiety instead of resin-bound carbodiimide, an N-alkyl substitution is introduced specifically onto the 2-amino position. Combined with an alkylation step of the resin-bound amino acid prior to guanidinylation, all desired substitutions of the final products are achieved without racemization at chiral centers. This reaction sequence is also compatible with a variety of protected amino acid side chains.     

Facile one-pot synthesis of 5-aryl/heterylidene-2-(2-hydroxyethyl- and 3-hydroxypropylamino)-thiazol-4-ones via catalytic aminolysis

A multicomponent synthetic approach for 5-aryl/heterylidene-2-(2-hydroxyethylamino)- and 2-(3-hydroxypropylamino)-thiazol-4-ones starting from 2-thioxothiazolidin-4-one or 2-methylsulfanylthiazol-4-one was developed. The proposed method involves simultaneous aminolysis of 2-thioxo- or 2-methylsulfanyl groups and Knoevenagel condensation with (hetero)aromatic aldehydes using 2-aminoethanol or 3-aminopropan-1-ol as catalysts. Side-chain prototropic amino–imino tautomerism was observed for target 5-ylidene-2-alkylaminothiazol-4-ones.     

Reaction of 2-(2-oxoethylidene)furan-3(2H)-ones with isopropylidenehydrazides of aromatic carboxylic acids: Synthesis of 3-hydroxy-3-(2-oxoethyl)-2,3-dihydropyridazin-4(1H)-ones

3-Hydroxy-3-(2-oxoethyl)-6-phenyl-2,3-dihydropyridazin-4(1H)-ones were obtained by the reaction of methyl 3-oxo-5-phenylfuran-2(3H)-ylideneacetate or 2-[2-(4-chlorophenyl)-2-oxoethylidene]-5-phenylfuran-3(2H)-one with benzoic or p-nitrobenzoic isopropylidenehydrazides. Equilibrium C₍₅₎H and C₍₅₎H₂ tautomeric forms were detected in solutions of the 4-chlorophenyl derivatives in DMSO-d₆. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1156–1158, August, 2007.     

Facile chemoselective rhodium carbenoid N-H insertion reactions: synthesis of 3-arylamino- or 3-heteroarylpiperidin-2-ones

Rhodium(II) acetate catalyzed reactions of various substituted 3-diazopiperidin-2-ones with a range of aromatic amines, indoles, and benzotriazole yield exclusively the corresponding N-H insertion products despite competing C-H or O-H insertions. This strategy provides an example of a facile chemoselective N-H insertion reaction delivering a library of 3-arylamino and 3-heteroarylpiperidin-2-one derivatives in high yields.     

Rapid microwave assisted synthesis of 3-substituted 4-thioxo-oxazolidin-2-ones

The microwave assisted thionation of 3-substituted 4-imino-oxazolidin-2-ones with hydrogen sulfide in dichloromethane-pyridine afforded 3-substituted 4-thioxo-oxazolidin-2-ones.     

Synthesis,properties, and mass-spectrometric fragmentation of 2-thio derivatives of 3-arylquinazolin-4-ones

We have studied the reactions of alkylation, oxidation, and hydrolysis of 3-aryl-2-thioxoquinazolin-4-ones. Alkylation in an alkaline medium occurs exclusively at the sulfur atom. Oxidation by hydrogen peroxide leads to formation of 3-arylquinazoline-2,4-diones. The latter are also obtained in base or acid hydrolysis of the synthesized S-alkyl derivatives. When 3-aryl-2-thioxoquinazolin-4-ones are reacted with iodine, we obtain the disulfides, while the reaction with chlorine in hydrochloric acid leads to 2-chloroquinazolin-4-ones. Studying the mass spectrometric behavior of the compounds obtained made it possible to observe in the gas phase ring-chain isomerization of the heterocyclic ring, and also S-N migration of the propargyl radical in molecular ions of the S-propargyl derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 440–446, March, 2007.     

Efficient,Stereoselective Approach to the Synthesis of 3-(1-Phenyl-2-(Z-styrylsulfonyl)-1H-imidazol-4-yl)-2H-chromen-2-ones

Reaction of phenyl acetylene with 3-(1-aryl-2-mercapto-4-imidazolyl)-2H-1-benzopyran-2-ones (4) in the presence of sodium hydroxide in absolute ethanol led to the formation of 3-(1-phenyl-2-(Z-styrylthio)-1H-imidazol-4-yl)-2H-chromen-2-ones (6) in excellent yields. These, on further oxidation with H₂O₂/AcOH, gave the corresponding sulfones (7) with retention of stereochemistry.

Camps reaction for the synthesis of 3-RS-4-arylquinolin-2-ones

The replacement of the chlorine atom in 2-(chloroacetamido)benzophenones on treatment with RSH (R = Alk, Ar, Hetaryl) in the presence of MeONa is accompanied by intramolecular cyclization following the Camps reaction pattern to give 3-RS-4-arylquinolin-2-ones. Cleavage of 4-aryl-3-(benzoxazol-2-ylthio)quinolin-2-ones by morpholine has resulted in the corresponding 4-aryl-3-mercaptoquinolin-2-ones.     

2-芳基-2,3-二氢4(1H)-喹唑啉酮类化合物的合成

在NaHSO4催化下,以苯甲醛和邻氨基苯甲酰胺为底物,在室温下合成了一系列2-芳基-2,3-二氢-4(1H)-喹唑啉酮类化合物,该反应产率高、操作简单、并且避免使用有毒的金属催化剂.     

An efficient synthesis of 2-amino-3-cyano-2-pyrrolin-4-ones, via the corresponding open chain tautomers (aminoacetylmalononitriles)

Malononitrile has been found to be acylated effectively using N-protected glycines by simultaneous activation of an amino acid carbonyl group and a malononitrile methylene group using carbonyl diimidazole (CDI). The corresponding aminoacetonitriles were isolated as enols and/or as their tautomeric forms, 2-amino-3-cyano-2-pyrrolin-4-ones.     

Practical and high stereoselective synthesis of 3-(arylmethylene)isoindolin-1-ones from 2-formylbenzoic acid

Practical and high stereoselective synthesis of 3-(arylmethylene)isoindolin-1-ones is reported. The synthetic method involves the preparation of dimethyl isoindolin-1-one-3-yl-phosphonates by a ‘one-pot’ three-component reaction of 2-formylbenzoic acid with 4-methoxybenzylamine or aminoacetaldehyde dimethyl acetal and dimethyl phosphite under solvent and catalyst free-conditions, followed by a Horner reaction with several aryl aldehydes.     

Synthesis and Anti-HIV-1 Activity of 2-[2-(3,5-Dimethylphenoxy)ethylthio]pyrimidin-4(3H)-ones

New 2-[2-(3,5-dimethylphenoxy)ethyl]thio derivatives of pyrimidin-4(3H)-one containing various substituents at positions 5 and 6 of the pyrimidine ring were synthesized. It was shown that alkylation of 2-thiouracils with 1-bromo-2-(3,5-dimethylphenoxy)ethane in DMF takes place exclusively at the sulfur atom. The obtained 6-benzyl and 6-(2,6-difluorobenzyl) derivatives have clearly defined virus-inhibiting properties with respect to type 1 human immunodeficiency virus in vitro and suppress its reproduction by 50% at concentrations of 1.3 and 11.2 mM respectively.     

Synthesis of 5-substituted 4-aminoalkylpyrazol-3-ones (isoxazol-3-ones) from 3-acyllactams

Structurally various 3-acyllactams act as 1,3-bielectrophiles in heterocyclization reactions with a variety of hydrazines and hydroxylamines to give aminoalkylpyrazolones and -isoxazol-ones in high yields.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 215–220, January, 2005.     

Thioureas from 3-aminoquinazolin-4(3H)-one. 2. Unusual alkaline recyclization of 3-(N",N",S-trialkylisothioureido)quinazolin-4(3H)-ones into new 1,3,4-oxadiazoles

3-(N",N",S-trialkylisothioureido)quinazolin-4(3H)-ones obtained by the reactions of 3-(N",N"-dialkylthioureido)quinazolin-4(3H)-ones with alkyl halides undergo unusual recyclization into 5-(2-aminophenyl)-2-dialkylamino-1,3,4-oxadiazoles under the action of aqueous solutions of alkali, hydrazine, and primary aliphatic amines. A plausible mechanism of the recyclization was proposed.     

Photochemical and thermal cyclizations of 4-(2-azidophenyl)-3,4-dihydropyrimidin-2-ones for the synthesis of 4-methylenepyrimidino[5,4-b]indol-2-ones

Photochemical and thermal cyclization of 4-(2-azidophenyl)-3,4-dihydropyrimidin-2-ones could afford fused indoles, such as 1,2,3a,9b-tetrahydro-4-methylenepyrimidino[5,4-b]indol-2-ones and 1,3,5,6,7a,12b-hexahydroquinazolino[9,4-b]indol-2,7-dione in high yields via nitrene electrophilic addition and rearrangement reactions.     

Facile stereoselective synthesis of 1,3-disubstituted-4-trichloromethyl azetidin-2-ones

The highly stereoselective synthesis of 1,3-disubstituted-4-trichloromethyl azetidin-2-ones by the [2+2] cycloaddition of ketenes with imines derived from chloral is described.