Formylation of 5-alkyl-3H-furan-2-ones

3-Formyl derivatives of 3H-furanones and 2-chlorofurans are formed in the reaction of 5-alkyl-3H-furan-2-ones with POCl₃ and DMF. The conditions for the purposeful synthesis of these compounds were found. The transformations of the formyl group in reactions with dinitrophenylhydrazine and aniline were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 456–458, April, 1993.     

Synthesis of 5-alkyl-3H-thiolen-2-ones and 5-alkyl-3H-furan-2-ones and condensation reactions at the heterocyclic methylene group

The intramolecular cyclization of -ketocarboxylic acids and their esters gives 5-alkylsubstituted 3H-thiolen-2-ones and 3H-furan-2-ones. It was shown that reaction occurred at the heterocyclic methylene group and that the conditions under which the reaction took place depended on the nature of the heterocyclic atom.Translated from Khimiya Geterotsiklicheskikh Soedinnenii, No. 4, pp. 451–454, April, 1987.     

Phase-transfer catalysis in reactions of 5-alkyl-3H-furan-2-ones with dichlorocarbene

Treatment of 5-alkyl-3H-furan-2-ones and 5-alkyl-3H-thiophen-2-ones with dichlorocarbene under conditions of phase-transfer catalysis at 20–90 °C results in insertion of the carbene at the C=C bond followed by skeletal rearrangement.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1995–1997, October, 1995.     

Regiospecific alkylation of tetronic acids : Formation of 4-alkoxy-5H-furan-2-ones and 2-alkoxy-5H-furan-4-ones

2-Alkoxy-5$\text{H}$-furan-4-ones (7,8) and 4-alkoxy-5$\text{H}$-furan-2-ones (4,5) were prepared regiospecifically and in high yields from tetronic acids (4-hydroxy-5$\text{H}$-furan-2-ones) (2) in the first case by acetylating the 4-OH group and then reacting with trialkyloxonium tetrafluoroborate, and in the second case by alkylating tetrabutylammonium tetronates with dialkyl sulfate, respectively. Direct alkylation of tetronic acids with trialkyloxonium tetrafluoroborate gave in four cases regiospecific 2-O-alkylation, in one case 4-O-alkylation and in two other cases mixtures of 2- and 4-alkoxy derivatives.     

Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3h-cycloheptimidazol-4-ones and 2-alkyl-3h-cycloheptimidazol-4-ones

Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (1) and 2-alkyl-3H-cycloheptimidazol-4-one (2) was investigated. 3-[2'-(1-tert-Butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-1H-cycloheptimidazol-4-one (6) was preferentially obtained under the conditions by using NaH in DMF or THF. On the other hand, 3-[2'-(1-tert-butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (5), the synthetic intermediate compound of Pratosartan, was obtained selectively in the presence of n-Bu(4)NBr in toluene by using aqueous sodium hydroxide as a base. In this reaction, it was found that the concentration of the alkaline solution influences its regioselectivity. This selectivity was observed even for aldehyde and ester derivatives.     

The Synthesis of 2-Alkylthio-3-alkyl-5-arylmethylidene4H-imidazol-4-ones

2-alkylthio-3-alkyl-5-arylmethylidene-4H-imidazol-4-ones were synthesized by the S-alkylation and N-alkylation of 2-thioxo-5-arylmethylidene-4-imidazolidinones, which were obtained via a tandem aza-Wittig reaction of vinyliminophosphoranes, carbon disulfide, and excess ammonium hydroxide (28% NH₃ in water).     

Arylmethylene derivatives of 5-R-3H-furan-2-ones and N-aryl-5-R-3H-pyrrol-2-ones in reaction with acetylacetone

Reaction with acetylacetone in the series of 3-arylmethylene-substituted furan-2-ones and pyrrol-2-ones was studied. 8-R-4-Acyl-5-aryl-3-oxo-9-oxabicyclo[4.3.0]nona-1,7-dienes and N-tolyl-8-R-4-acyl-5-aryl-3-oxo-9-azabicyclo[4.3.0]nona-1,7-dienes were synthesized. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1457–1462, October, 2007.     

Acetylation of 6-alkyl-5-ethoxycarbonyl-2-hydroxy-4-methyl-dihydropyrimidines and their 2-mercapto analogs

A number of 6-alkyl- and 6-aryl-5-ethoxycarbonyl-2-hydroxy-4-methyldihydropyrimidines and their 2-mercapto analogs and the acetyl derivatives of these compounds have been synthesized. In each case, two isomeric acetyl derivatives were obtained, probably the 1- and 3-acetyl compounds.     

Reaction of 3-arylhydrazono-3H-furan-2-ones with o-phenylenediamine

Depending on the conditions, 3-arylhydrazono-3H-furan-2-ones reacted with o-phenylenediamine along two pathways with formation of 2-hydrazonotetrahydrobenzopyrrolo[1,2-a]imidazol-1-ones and 2-(1-aryl-1H-pyrazol-3-yl)benzimidazoles.     

Some characteristic properties of 3-alkyl-2-thiothiazon-4-ones and of intermediates in their synthesis

Acrylonitrile reacts with dithiocarbaminates to give nitriles of N-alkyl-S-thiocarbaminylthiohydracrylic acids, which are then hydrolyzed to the corresponding amides and acids. Dehydration of the latter gives 3-alkyl-2-thiothiazon-4-ones. The UV spectra of N-alkyl-S-thiocarbaminylthiohydracrylic acids, and amides and nitriles of them are characterized by two maxima in the 245–250 nm (thioamide band) and 266–280 nm (dithiocarbonate band) regions. Thiazan ring closure results in bathochromic shift of absorption maxima due to lengthening of the conjugated chain. The average values of the atomic refraction for sulfur in the molecules of the compounds investigated correspond to a thioketone structure.     

Synthesis and Diels-Alder reactions of 2-alkyl-5-methylene-1,3-dioxolan-4-ones and 2-alkyl-3-acyl-5-methylene-1,3-oxazolidin-4-ones: Highly exo and diastereoface selective chiral ketene equivalents

Chiral dienophiles 1–3 undergo highly exo and diastereoface selective Diels-Alder reactions. The Diels-Alder reactions of 3 are also highly exo selective under Lewis acid catalyzed conditions.     

Michael condensation of 3-arylidene-3H-pyrrol-2-ones and 3-arylidene-3H-furan-2-ones with cyclohexanone

The Michael condensation in the series of 5-aryl-3-arylidene-3H-pyrrol-2-ones and 5-aryl-3-arylidene-3H-furan-2-ones, containing an activated C=C bond, with cyclohexanone was investigated. It was shown that the condensation products were 1,5-dicarbonyl compounds containing a heterocyclic fragment. The enolization of one of the oxo groups, leading to the formation of hydroxypyrrole or hydroxyfuran structures, was demonstrated by the spectral data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–827, June, 2007.     

Substitution of 3H-furan-2-ones in amination and hydroamination reactions

The amination and hydroatnination of 5-alkyl-3H-furan-2-ones and their 3-benzylidene- and 3 formyl-derivatives were studied. The characteristics of the reactions, the requirements for the nature of the nucleophilic reagents, and the reaction conditions leading to the destruction of the furan ring and recyclization to pyrrolidinone and pyrrolinone structures are indicated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 349–352, March, 1994.     

Synthesis of 1-alkyl-2-methylazetidin-3-ones and 1-alkyl-2-methylazetidin-3-ols

Several 1-alkyl-2-methylazetidin-3-ones were prepared in good yield by the hydride-induced cyclization of the corresponding β-bromo-α,α-dimethoxyketimines, the resulting 3,3-dimethoxyazetidines being hydrolyzed by acid. Imination of these 1,2-disubstituted azetidin-3-ones, followed by alkylation under kinetic control conditions resulted in regioisomeric mixtures of 2,4- and 2,2-dialkylated compounds. Analytical samples of the major 2,4-disubstituted derivatives were obtained after extensive chromatographic separation. The cis stereochemistry of the major 2,4-dialkylated isomer was demonstrated on the basis of NMR data.     

5-烷氧基-4-环胺基-3-卤-2(5H)-呋喃酮的合成与表征

在氟化钾作用下,亲核试剂环状仲胺与5-烷氧基-3,4二卤-2(5H)-呋喃酮在室温下发生串联的迈克尔加成-消除反应,合成了17个新化合物.通过旋光度,UV-Vis,IR,1H NMR,13C NMR,MS,元素分析和X射线单晶衍射等表征方法,确定了目标化合物的化学结构和绝对构型.     

Regio- and stereoselective microwave-assisted synthesis of 5-alkyl-4-alkenyl-4-phenyl-1,3-oxazolidin-2-ones

Chiral symmetrical alk-2-yne-1,4-diols have been stereoselectively transformed into 5-alkyl-4-alkenyl-4-phenyl-1,3-oxazolidin-2-ones, which are precursors of quaternary α-amino β-hydroxy acids. The key step was the cyclization of the bis(tosylcarbamates) of 2-phenylalk-2-yne-1,4-diols, easily obtained from the starting chiral diols. These cyclizations were accomplished with complete regioselectivity and up to 92:8 dr in the presence of catalytic amounts of Ni(0) or Pd (II) derivatives under microwave heating.     

Synthesis and Antinociceptive Activity of Substituted 5-(Het)aryl-3-(4-methylbenzoyl)hydrazono-3H-furan-2-ones

Russian Journal of General Chemistry - The method was proposed for the synthesis of new substituted 5-(het)aryl-3-(4-methylbenzoyl)hydrazono-3H-furan-2-ones by intramolecular cyclization of...