Reactions of Acylpyruvic Acids and 2,3-Dihydrofuran-2,3-diones with 2,3-Diaminopyridine

Acylpyruvic acids readily react with 2,3-diaminopyridine to form (Z)-3-acylmethylene-1H-3,4-di- hydropyrido[2,3-b]pyrazin-2-ones. 5-Aryl-2,3-dihydrofuran-2,3-diones which can be regarded as lactones derived from -enolized aroylpyruvic acids react with 2,3-diaminopyridine under mild conditions, yielding regioisomeric (Z)-2-aroylmethylene-4H-1,2-dihydropyrido[2,3-b]pyrazin-3-ones. The structure of the products and reaction chemoselectivity are discussed.     

Pyrrolidine-2,3-dione, 1-allylpyrrolidine-2,3-dione and 1-ethoxypyrrolidine-2,3-dione

Authentic pyrrolidine-2,3-dione has been prepared by two different routes. It is shown that the material previously reported is actually a hydrolysis product, 4-amino-2-oxobutyric acid. 1-Allyl- and 1-ethoxypyrroli-dine-2,3-dione have been prepared as N-protected pyrrolidine-2,3-diones potentially useful in synthesis.     

2,3-Benzodiazepine-1-thione in the synthesis of substituted and hetero-annelated 2,3-benzodiazepines

A series of S-substituted and 1,2-annelated derivatives of 2,3-benzodiazepine has been obtained on the basis of 2,3-benzodiazepine-1-thione. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 594-601, April, 2009.     

Thieno[2,3-d]pyrimidin-4-ones 1. Condensation of 2,3-dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-7,8-dihydro-pyrrolo[1,2-a]thieno[2,3-d]pyriminidin-4(6H)-ones with aromatic aldehydes and furfural

2,3-Dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-substituted 8-arylidene-6,7-dihydro-pyrrolo[1,2-a]thieno[2,3-d]pyrimidin-4-ones were synthesized by the reaction of 2,3-dimethyl- and 2,3-tri-, 2,3-tetra-, and 2,3-pentamethylene-7,8-dihydropyrrolo[1,2-a]thieno[2,3-d]pyrimidin-4(6H)-ones with benzaldehyde, its 4-dimethylamino-, 3,4-dimethoxy-, and 3,4-methylenedioxy derivatives and also furfural in the presence of NaOH.     

Synthesis and stereochemistry of trans- and cis-2,3-difluoro-2,3-dihydrobenzofuran

The geometrical isomers of 2,3-difluoro-2,3-dihydrobenzofuran have been prepared and their structure assigned on the basis of the nmr spectra. Some suggestions on the conformational situation of two adducts are also reported.     

Synthesis of 5-R-3-Diphenylmethylene-2,3-dihydro-2-furanones from 5-Substituted 2,3-Dihydro-2,3-furandiones and Phenylbenzoyldiazomethane

3-Reactions of 5-aryl, 5-heteryl, and 5-styryl-2,3-dihydro-2,3-furandiones with phenylbenzoyldiazomethane gave rise to 5-substituted 3-dipenylmethylene-2,3-dihydro2-furanones. The possible intermediates and reaction products were investigated by semiempirical SCF MO LCAO method in AM1 approximation.     

Electrochemical Synthesis of 2,3-Dimethyl-2,3-Dinitrobutane

Anodic oxidation of 2-nitropropane in a methanol solution of sodium iodide and hydroxide is found to produce 2,3-dimethyl-2,3-dinitrobutane with a yield of 65-70% under optimum conditions. Deceased.     

Decyclization of 5-Aryl-4-methyl-2,3-dihydrofuran-2,3-diones by the Action of Nucleophiles

Ring cleavage in 4-methyl-5-phenyl-2,3-dihydrofuran-2,3-dione by the action of methanol and in 5-aryl-4-methyl-2,3-dihydrofuran-2,3-diones by the action of aniline and N-methylaniline results in formation of, respectively, methyl 3-methyl-4-phenyl-2,4-dioxobutanoate and 4-aryl-3-methyl-2,4-dioxobutananilides. The reaction mechanism was studied by ¹H NMR spectroscopy.     

Synthesis of 2,3-dioxo-2,3-dihydro-4-methyl-6-chloro-1H-pyrrolo[2,3-b]pyridine and its 1-α-L-arabinopyranoside

A new type of isatin analog-2,3-dioxo-2,3-dihydro-4-methyl-6-chloro-1H-pyrrolo[2,3-b]pyridine — was obtained by oxidation of 4-methyl-6-chloro-1H-pyrrolo(2,3-b]pyridine. Condensation of L-arabinose with 4-methyl-6-chloro-2,3-dihydropyrrolo[2,3-b]pyridine and subsequent acetylation and dehydrogenation gave 1-(2,3,4-tri-O-acetyl--L-arabinopyranosyl)-4-methyl-6-chloropyrrolo[2,3-b]pyridine, which served as the starting compound for the synthesis of 1--L-arabinopyranosyl-4-methyl-6-chloropyrrolo[2,3-b]pyridine. Oxidation of 1-(2,3,4-tri-O-acetyl-L-arabinopyranosyl)-4-methyl-6-chloropyrrolo[2,3-b]pyridine gave 1-(2,3.4-tri-O-acetyl--L-arabinopyranosyl)-2,3-dioxo-2,3-dihydro-4-methyl-6-chloropyrrolo [2,3-b]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1083–1086, August, 1977.     

Diastereoselective protocols for the synthesis of 2,3-trans- and 2,3-cis-6-methoxy-morpholine-2-carboxylic acid derivatives

Two diastereoselective and straightforward protocols for the high-yielding synthesis of 2,3-trans- and 2,3-cis-6-methoxy-3-substituted morpholine-2-carboxylic esters were realized in few steps, through the condensation between 5,6-diethoxy-5,6-dimethyl-1,4-dioxan-2-one and an appropriate imine, which is the key reaction to control the C2-C3 relative stereochemistry, followed by a methanolysis/ring-closure tandem reaction sequence. In particular, 2,3-trans-morpholines derive from the R*,S*-product of the acid condensation of N-functionalized alkylimines with the silylketene acetal of the above lactone, whereas 2,3-cis-morpholines derive from the R*,R*-product of basic condensation of an N-tosylimines with the lactone.     

Investigations in the Field of 2,3'-Biquinolyl. 14. Reaction of Dihydro Derivatives of 2,3'-Biquinolyl with Bromine and Iodine

Methods were developed for the synthesis of 6'-bromo- and 6',8'-dibromo-2,3'-biquinolyls and 3',4'-dibromo- and 3',4',6'-tribromo-1'-ethoxycarbonyl-1',2',3',4'-tetrahydro-2,3'-biquinolyls on the basis of the bromination of the dihydro derivatives of 2,3'-biquinolyl. It was shown that the reaction of 1'-alkyl-1',4'-dihydro-2,3'-biquinolyls with bromine and iodine leads to 1'-alkyl-1',2'-dihydro-2,3'-biquinolyl-2'-ones.     

Synthesis of 2,3-diaryl-1,4-diazolyl-2,3-epoxybutanes

2,3-Diaryl-1,4-diazolyl-2,3-epoxybutanes have been prepared from dimethylstilbenes. An efficient although neglected synthesis of the required olefins has been recovered from the literature. The target compounds show moderate antifungal activity.     

A Method for the Synthesis of 2,3-Disubstituted 2,3-Dihydrobenzofurans

Summary.  The synthesis of 2,3-disubstituted 2,3-dihydrobenzofuran diastereomers is described. The key step in the reaction sequence is the chemoselective reduction of a tert. alcohole with tert.-butylamine-borane/AlCl₃. The relative configuration of the substituents on the dihydrofurane moiety was assigned via NMR spectroscopy. Received September 7, 1999. Accepted November 9, 1999     

Preparation and characterization of 2,3-dihydro-2,3 bis (methylene) furan

2,3-dihydro-2,3 bis (methylene) furan and its 4-methyl derivative have been prepared by flash vacuum thermolysis and characterized by mass spectrometry and chemical trapping.     

Five-membered 2,3-dioxoheterocycles 3. The reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with aliphatic and aromatic nitriles

On reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with -aminoisobutyronitrile, o-aminobenzonitrile, and -anilinopropiononitrile, we obtained aroylpyruvic acid N-(1-methyl-1-cyanoethyl)-, N-(o-cyanophenyl)-, and N-phenyl-N-(cyanoethyl)-amides, respectively. On reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with cyanoacetamide we obtained aroylacetic acid N-(cyanoacetyl)amides, while in the case of methyleneaminoacetonitrile and p-dimethylaminobenzonitrile we obtained (6-aryl-4-oxo-2,3-dihydro-1,3-oxazin-3-yl)acetonitriles and 2-(p-dimethylaminophenyl)-6-aryl-1,3-oxazine-4-ones, respectively.For Communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 740–743, June, 1987.     

内消旋-和外消旋-2,3-二氰基-2,3-二苯基丁二酸二乙酯的热异构化反应

用高效液相色谱法测定了2,3-二氰基-2,3-二苯基丁二酸二乙酯的内消旋体(1)和外消旋体(2)在1,1,2,2-四氯乙烷中的热异构化反应动力学和活化参数。结果表明,在热力学上2比1更稳定,并从它们的构型与形成空间键的能力间的关系给予解释。     

Five-Membered 2,3-Dioxo Heterocycles: XLV. Thermolysis of 5-Aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the Absence of Other Partners and in the Presence of Carbonyl Compounds

Aroyl(phenyl)ketenes generated by thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones undergo [4+2]-cyclodimerization to 3-aroyl-6-aryl-3,5-diphenyl-3,4-dihydro-2H-pyran-2,4-diones. Heating of the latter leads to rearrangement with formation of 4-aroyloxy-6-aryl-3,5-diphenyl-2H-pyran-2-ones. Thermolysis of 5-aryl-4-phenyl-2,3-dihydrofuran-2,3-diones in the presence of carbonyl compounds yields 6-aryl-5-phenyl-4H-1,3-dioxin-4-ones.     

Synthesis of pyrazine-2,3-dicarbonitriles via the one-pot three-component reaction of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione,diaminomaleonitrile, and functionalized alcohols in acetonitrile

An efficient one-pot three-component reaction of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione, diaminomaleonitrile, and alcohols with hetero-atom substituents or several hydroxyl groups in acetonitrile solvent under reflux led to the formation of 5-(2-substituted ethoxy or propoxy-2-phenyl-1-N-phenylthiocarbamoylethenyl)-6-oxo-1,6-dihydropyrazine-2,3-dicarbonitrile derivatives in good yields.     

Generation and trapping of 2,3-naphthoquinone

2,3-Naphthoquinone generated from 2,3-dihydroxynaphthalene was trapped with cyclopentadiene and its properties examined by dc polarography and cyclic voltametry.     

Development of new methods for the synthesis of 2,3-bis(nitroxymethyl)-2,3-dinitrobutane-1,4-diol dinitrate and its intermediates

Known methods for the synthesis of 2,3-bis(nitroxymethyl)-2,3-dinitrobutane-1,4-diol dinitrate and its intermediates were investigated. New procedures were developed for the preparation of these compounds. 2,3-Bis(nitroxymethyl)-2,3-dinitrobutane-1,4-diol dinitrate was studied by X-ray diffraction.