Short synthesis of 4-aryl-3-pyrrolin-2-ones

A three step, convergent synthesis of 4-aryl-3-pyrrolin-2-ones from a tetramic acid has been developed. The key transformation utilized a Suzuki-Miyaura cross-coupling reaction between a 4-tosyloxy-3-pyrrolin-2-one and an arylboronic acid. This work also provides access to 4-arylpyrrolidin-2-ones, cyclic analogs of γ-aminobutyric acid (GABA). Hydrogenation of 4-(4′-chlorophenyl)-3-pyrrolin-2-one proceeded smoothly to give baclofen lactam.     

Nucleophilic Addition of Amines to N-Aryl-substituted Pyrrolin-2-ones

The nucleophilic addition of n-butyl- and benzylamines to 1-(4-nitrophenyl)-5H-pyrrolin-5-one and 1-(4-sulfamoylphenyl)-5H-pyrrolin-2-one at 50°C in an excess of the amines with the formation of N-substituted amides of 3-alkyl(benzyl)amino-4-(4-R-anilino)butyric acids was investigated. The N-substituted amides of 3-arylamino-4-hydroxybutyric and 4-hydroxy-2-butenoic acids were synthesized from 2(5H)-furanone and aromatic amines (1:3) at 180°C. 4-Alkylamino-1-(4-nitrophenyl)pyrrolid-2-ones were obtained in the reaction of 1-(4-nitrophenyl)-5-pyrrolin-2-one with ammonia or aliphatic, alicyclic, and aromatic amines (1:3, 90°C, in DMF).     

1-Oxa-3-azapentalen-2-ones as Precursors of cis-2-Amino Alcohols: Synthesis from Propargyl Alcohols, CO2, and Amines Using an Intramolecular Amidoalkylation Reaction of Oxazolidin-2-ones

The reaction of 5-methyl-5-(4-methyl-3-pentenyl)-4-methylene-1,3-dioxolan-2-one with primary amines gives the corresponding 4-hydroxy-4-methyloxazolidin-2-ones. These undergo an intramolecular amidoalkylation reaction to form 1-oxa-3-azapentalen-2-ones which are potential precursors of cyclopentanyl cis-2-amino alcohols.     

A study of the reaction of 2-thiazolin-4-ones with some electrophiles under microwave irradiation versus conventional condition

Coupling of 5-dimethylaminomethylene-3-methyl-2-(pyridine-2-ylimino)-thiazolidin-4-one (3) with diazotized methyl anthranilate afforded the 3-methyl-5-(2-methoxycarbonylphenylhydrazono)-2-pyridine-2-ylimino)thiazolidin-4-one (5). Reaction of 2-(arylamino)thiazol-4-ones 1a,b with arylidenemalononitriles under microwave irradiation gave 2-substituted amino-5-arylidenethiazolin-4-ones 9a–f. Alternatively, compound 9 could also be obtained by reacting compound 1 with aromatic aldehydes. Treatment of compound 9 with acetic acid yielded the corresponding thiazolin-2,4-diones 10. However, the reaction of 1 with cyanoacetic acid yielded the corresponding 4-cyanoacetyl derivative 12, in good yield. The ¹H, ¹³C NMR spectra of some representative products and X-ray crystal structure determination are discussed.     

Synthesis of Some Novel 5-(Arylidene)-2-imino-3(pyridin-2-yl)thiazolidin-4-one Derivatives

Treatment of 2-aminopyridine ( 1 ) with chloroacetyl chloride in dry benzene gave 2-chloro-N-(pyridin-2-yl)acetamide ( 3 ), which on further reaction with potassium thiocyanate gave 2-imino-3-(pyridin-2-yl)thiazolidin-4-one ( 4 ) as an intermediate compound for the synthesis of pyridin-2-yl substituted 2-imino-thiazolidine-4-one derivatives. Cyclocondensation reaction of ( 4 ) with a series of aromatic aldehydes gave 5-arylidene derivatives of pyridin-2-yl substituted 2-imino-thiazolidine-4-ones 5a–j . ¹ H and ¹³C NMR spectroscopy, as well as elemental analyses, were used for the identification of these new compounds.     

Synthesis of 2-aryl-5H-[1,3,4]-thiadiazolo[2,3-b]quinazolin-5-ones

3-Amino-2-thioxo-1,2,3,4-tetrahydroquinazolin-4-ones were converted into 2-aryl-5H-[1,3,4]thiadiazolo[2,3-b]quinazolin-5-ones on treatment with carboxylic acids and POCl₃. 3-Arylmethylidenamino-2-thioxo-1,2,3,4-tetrahydroquinazolin-4-ones also cyclized to 2-aryl-5H-[1,3,4]thiadiazolo[2,3-b]quinazolin-5-ones when oxidized with potassium chlorate in acetic acid, but on heating they were deaminated to give 2-thioxo-1,2,3,4-tetrahydroquinazolin-4-one and aryl nitriles. __________ Translated from Khimiya Geteotsiklicheskikh Soedinenii, No. 5, 787–791, May, 2006.     

An efficient synthesis of novel benzo[b]pyrido[3',2':4,5] thieno[2,3-e][1,6]naphthy-ridine-8-ones

An efficient method for the synthesis of novel benzo[b]pyrido[3',2':4,5] thieno[2,3-e][1,6] naphthyridine-8-one derivatives has been developed using a Pictet-Spengler reaction between 4-(3-aminothieno[2,3-b]pyridin-2-yl)quinoline-2-ones, which could be obtained from the alkylation of 4-bromomethylquinoline-2-ones with 3-cyanopyridine-2-thione followed by a Thorpe-Ziegler isomerization, and aromatic aldehydes under p-TsOH as catalysis in good yields.     

Synthesis and structure of 1,3-dialkyl-4-(sulfonylimino)imidazolidin-2-ones

The reactions of 1,3-dialkyl-4,5-dihydroxyimidazolidin-2-ones with alkyl sulfamides have been studied and previously undescribed 1,3-dialkyl-4-(alkylaminosulfonylimino)imidazolidin-2-ones have been obtained. The structure of 1,3-dimethyl-4-(benzenesulfonylimino)imidazolidin-2-one was investigated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1159–1166, August, 2007.     

由N-苯基[1,3]苯并噁嗪正离子与烯烃[4+2]反应合成喹啉并[1,2-c][1,3]苯并噁嗪-6-酮衍生物

以BF3·OEt2 为催化剂, 在室温下通过4-羟基-N-苯基[1,3]苯并噁嗪-2-酮的脱羟基产生N-苯基[1,3]苯并噁嗪正离子, 然后与富电子烯烃发生Diels-Alder反应, 合成出了一系列喹啉并[1,2-c][1,3]苯并噁嗪-6-酮和喹啉并[1,2-c][1,3]萘并噁嗪-6-酮衍生物.     

Synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3-e][1,6]naphthyridine-8-ones via Pictet–Spengler cyclization

An efficient method for the synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3e]-[1,6]naphthyridine-8-one derivatives via Pictet–Spengler cyclization is reported. The reaction of 4-(3-aminopyrimido[4,5-d]thieno-2-yl)quinoline-2-ones, which could be obtained from Thorpe–Ziegler isomerization of 4-bromomethylquinoline-2-ones and 5-cyano-1,6-dihydro-4-methyl-2-phenyl-6-thioxopyrimidine,with aromatic aldehydes in the presence of BF_3·OEt_2 gives pyrimidothieno[1,6]naphthyridines in good yields.     

2-Polyfluoroalkylchromones. 6. Synthesis of substituted 2-morpholino-2-trifluoromethylchroman-4-ones

Morpholine adds smoothly at the double bond of substituted 5- and 8-nitro-2-trifluoromethylchromones to form the corresponding 2-morpholino-2-trifluoromethylchroman-4-ones. 6-Methoxy-5-nitro-2-trifluoromethylchromone adds also benzylamine, whereas 7-methoxy-8-nitro-2-trifluoromethylchromone undergoes ring opening under the action of benzylamine to give 3-benzylamino-4,4,4-trifluoro-1-(2-hydroxy-4-methoxy-3-nitrophenyl)but-2-en-1-one.     

An efficient synthesis of benzo[b]benzofurano[2,3-e]-[1,6]naphthyridine-8-ones

An efficient method for the synthesis of benzo[b]benzofurano[2,3-e][1,6]naphthyridine-8-one derivatives has been developed via Pictet-Spengler reaction of 4-(3-aminobenzofuran-2-yl)quinoline-2-ones,which could be obtained from alkylation of 4-bromomethylquinoline-2-ones with salicylonitrile and subsequent Thorpe-Ziegier isomerization,with aromatic aldehydes under p-TsOH as catalyst in good yields.     

Synthesis of Novel 2-Iminothiazolidin-4-ones

Abstract

Thiazolidin-4-ones are known to exhibit diverse biological activities such as antimicrobial, anticancer, antidiarrheal, anticonvulsant, antidiabetic, antihistaminic, and antifungal activities. In the present investigation, a series of 2-haloacetamides was prepared by reacting chloroacetyl chloride with amines in dry benzene under reflux conditions. The formed 2-haloacetamides reacted with potassium thiocyanate in refluxing dry acetone to afford new 2-iminothiazolidin-4-ones. The 5-arylidene-2-imino-3 (napthalen-2yl)-thiazolidin-4-ones were prepared by condensing 2-iminothiazolidin-4-ones with substituted benzaldehydes. All the products were characterized by infrared, mass, and ¹H and ¹³C NMR techniques.     

5,6,7,8-Tetrafluoro-4-hydroxycoumarin derivatives in reactions with o-phenylenediamine

The reactions of 5,6,7,8-tetrafluoro-4-hydroxycoumarin derivatives with o-phenylenediamine occur with pyrone heterocycle cleavage and formation of substituted benzodiazepin-2-ones. 5,6,7,8-Tetrafluoro-4-hydroxycoumarin affords 4-(3,4,5,6-tetrafluoro-2-hydroxyphenyl)-2,3-dihydro-1H-1,5-benzodiazepin-2-one, 3-acetimidoyl-5,6,7,8-tetrafluoro-4-hydroxycoumarin produces 3-(3,4,5,6-tetrafluoro-2-hydroxybenzoyl)-4-methyl-1,2-dihydro-1H-1,5-benzodiazepin-2-one, and 3-acetyl-5,6,7,8-tetrafluoro-4-hydroxycoumarin yields both these heterocycles.     

4-Hydroxy-2-quinolones. 84. Synthesis of 5-R-5H-5,7a,12-Triazabenzo[a]anthracene-6,7-diones

2-Aminopyridines react under thermolysis conditions with ethyl 1-R-4-chloro-2-oxoquinoline-3-carboxylates exclusively in the imino form to give the corresponding 5-R-5H-5,7a,12-triazabenzo[a]anthracene-6,7-diones and 4-(pyridyl-2-amino)-1-R-quinolin-2-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1060–1070, July, 2005.     

Synthesis of 6- and 7-acyl-4H-benzothiazin-3-ones

Synthesis of 6- and 7-substituted benzoxazin-3-ones was already described in the literature by acylation of the corresponding benzoxazin-3-ones or cyclization of the corresponding 4- or 5-acyl-2-aminophenols. This paper describes original synthetic pathways to afford the 6- and 7-acyl products in the benzothiazin-3-one series, respectively, via Stille coupling reaction and by acylation.     

Urea/Thiourea as Ammonia Surrogate: A Catalyst-Free Synthesis of 2-Substituted 2,3-Dihydroquinazolin-4(1H)-ones/Quinazoline-4(3H)-ones

Urea/thiourea have been identified as an effective ammonia surrogate in the construction of quinazolin-4(3H)-one ring. This strategy afforded a simple and catalyst-free synthesis of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones via the reaction of isatoic anhydride and aryl aldehydes in the presence of urea or thiourea in ethanol. The reaction proceeded well to afford the quinazolin-4(3H)-one or its dihydro derivative, depending on the nature of carbonyl compounds employed.     

Synthesis of 5-[2-(Phenoxy)ethyl] Derivatives of 6-Methyluracil, 6-Methyl-2-thioxo-2,3-dihydro-1H-pyrimidin-4-one,and 2-Imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one

A synthesis of novel derivatives of 6-methyluracil, 6-methyl-2-thioxo-, and 2-imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one containing a 2-(phenoxy)ethyl substituent at position 5 of the pyrimidine ring has been carried out. It was found that 5-[2-(phenoxy)ethyl] derivatives of 6-methyl-2-thioxo- and 2-imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one are obtained by the condensation of the corresponding ethyl 3-oxo-2-(2-phenoxyethyl)butanoates with thiourea or guanidine. 6-Methyl-5-[2-(phenoxy)ethyl]uracils can be prepared by treating 6-methyl-5-[2-(phenoxy)ethyl]-2-thioxo-2,3-dihydro-1H-pyrimidin-4-ones with an excess of aqueous monochloroacetic acid solution. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1213–1217, August, 2005.     

Synthesis and photochromism of a series of new 2-unsubstituted 3-(2-benzylbenzoyl)quinolin-4(1H)-ones

Synthesis and characterization of a series of new 2-unsubstituted 3-(2-benzylbenzoyl)quinolin-4(1H)-ones is described. In addition to their potential biological activity, these compounds exhibit photoreversible photochromic properties in anaerobic conditions. Using the 1 and 2D NMR techniques we demonstrated that the coloration occurred owing to the formation of fluorescent 5a,6-dihydrobenzo[b]acridin-(5H)-ones. The photoreaction is stereoselective and the S,R-isomers are the major products (83%) whereas the S,S-isomers are the minor (6%). In addition, the irreversible formation of two oxidation products, 3-(2-benzoylbenzoyl)quinolin-4(1H)-ones, and acridin-12(5H)-one derivatives was observed in the presence of air.     

Synthesis of 2-Benzylidene and 2-Hetarylmethyl Derivatives of 2H-1,4-Benzoxazin-3-(4H)-ones as Neuroprotecting Agents

A wide variety of the title compounds were synthesized by conventional and microwave methods in which the main step is a condensation of an aldehyde with a 1,4-benzoxazin-3-(4H)-one. In all cases, the Z diasteromers were the major products. Of particular importance is the synthesis of novel 2-(3,5-dibromo-4-hydroxy) and 2-(4-acetoxy-3,5-dibromobenzylidene derivatives of 2H-1,4-benzoxazin-3-(4H)-ones, four of which were shown in a previous publication to exhibit potent neuroprotecting properties. The yields of titled compounds ranged from 25 to 83%.