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.     

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.     

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.     

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.     

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.     

Identification of 2,3-dimethyl-2,3-diisobutyl succinonitrile in laser printer emissions

2,3-Dimethyl-2,3-diisobutyl succinonitrile was identified as the main volatile organic compound (>90%) emitted from laser printers during the printing process. Experiments were carried out in a large environmental chamber of 30 m3, where the printers were placed and working simulating 'real office setting' conditions. Air samples were taken on Tenax TA adsorbent cartridges in the vicinity of the printers and further analyzed by thermal desorption gas chromatography/mass spectrometry (TDGC/MS). The structure of the compound has been determined and is presented in this study. Additional data obtained by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, and liquid chromatography/tandem mass spectrometry (LC/MS/MS) support the proposed structure, with no reported CAS number, as 2,3-dimethyl-2,3-diisobutyl succinonitrile. It is a byproduct of the thermal decomposition of 2,2'-azobis(2,4-dimethyl valeronitrile), a commercially available free radical polymerization initiator used in polymerization processes during the manufacture of the toners. By means of head-space GC/MS, 15 toners used in black & white and colour printers have been investigated. Six of them contained 2,3-dimethyl-2,3-diisobutyl succinonitrile, which has also been detected in the respective processed paper.     

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-dihydro-5H-oxazolo[2,3-B]quinazolin-5-ones

Iodide-catalyzed ring expansion of 2-[(1-aziridinylcarbonyl)amino]benzoic acid methyl ester (2) gave 2,3-dihydro-5H-oxazolo[2,3-b]quinazolin-5-one (3) in quantitative yield. Treatment of the dimethyl analog of 2 (9) with sodium iodide in acetone gave a mixture of the 2,3-dihydro-2,2-dimethyl- (10) and 2,3-dihydro-3,3-dimethyl-5H-oxazolo[2,3-b]quinazolin-5-ones (11). However, rearrangement of 9 with sulfuric acid produced only 10. Synthesis of 11 by another route for comparison is described, and the known syntheses of 2,3-dihydro-5H-oxazolo[2,3-b]quinazolin-5-ones are reviewed.     

Perfluoro-2,3-dimethylbutadiene

Conclusions 2,3-Bistrifluoromethyl-1,1,1,3,3,3-hexafluorobutane was obtained by the electrolysis of monohydro-perfluoroisobutyric acid, the dehydrofluorination of which gives perfluoro-2,3-dimethylbutadiene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp.459–460, February, 1973.     

Synthesis of 2,3-dihydrospiro[benzofuran-2,4′ -piperidines] and 2,3-dihydrospiro[benzofuran-2,3′-pyrrolidines]

The synthesis of 2,3-dihydrospiro[benzofuran-2,4′-piperidines] 3 and 2,3-dihydrospiro[benzofuran-2,3′]-pyrrolidine] 6 is described. The synthesis was achieved by a Grignard reaction of a 2-fluorobenzylhalide with an appropriate cycloazaalkyl ketone to yield the tertiary alcohols 1 and 4 . Subsequent intramolecular displacement of the aromatic fluoride by the derived alkoxides provided the novel system. Nitration of 1′-acetyl-2,3-dihydrospiro[benzofuran-2,4′-piperidine] 7 resulted in a 5-nitro derivative.     

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.     

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.     

Five-membered 2,3-dioxoheterocycles

The reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with benzamide oxime, diaminoglyoxime, and hydroxyurea gave 3-phenyl-5-aroylacetyl-1,2,4-oxadiazoles, 5,6-dihydroxyimino-3-phenacylidenepiperazin-2-ones, and 3-hydroxy-5-phenacylideneimidazolidine-2,4-diones, respectively. 6-Phenacylidene-5-oxo-4,5,6,7-tetrahydrofurazano [3,4-b]pyrazines are formed in the reaction of 5-aryl-2,3-dihydrofuran-2,3-diones with diaminofurazan.For Communication 7, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1457–1460, November, 1988.     

5-Arylfuran-2,3-diones

5-Arylfuran-2,3-diones were obtained by cyclization of aroylpyruvic acids in the presence of thionyl chloride. It is shown that the five-membered ring of 5-arylfuran-2,3-diones is unstable and is cleaved under mild conditions under the influence of nucleophilic reagents.     

Synthesis of 2,3-tetramethylene-5-arenesulfonamidobenzofurans

The reaction of N-arenesulfonyl-1,4-benzoquinonimines with 1-morpholino(piperidino)-1-cyclohexene gives 2,3-dihydro-2-morpholino(piperidino)-2,3-tetramethylene-5-arene-sulfonamidobenzofurans. Refluxing of the latter in dilute hydrochloric acid gave 2,3-tetramethylene-5-arenesulfonamidobenzofurans, the structure of which was proved by hydrolysis to 2,3-tetramethylene-5-aminobenzofuran and conversion of it to the previously described 2,3-tetramethylene-5-hydroxybenzofuran.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 872–874, July, 1972.     

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。     

Interaction of 4,5-diphenyl-2,3-dihydro-2,3-pyrroledione with ethoxycarbonylmethylenetriphenylphosphorane: synthesis and crystal structure of 4,5-diphenyl-Z-2-ethoxycarbonylmethylene-2,3-dihydro-3-pyrrolone

1-Unsubstituted 4,5-diphenyl-2,3-dihydro-2,3-pyrroledione interacts with ethoxycarbonyl-methylenetriphenylphosphorane regioselectively to give 4,5-diphenyl-Z-2-ethoxycarbonyl-methylene-2,3-dihydro-3-pyrrolone. The crystal and molecular structure of the latter was studied by X-ray analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1556–1558, August, 1995.     

丙酮肟氧化偶联合成2,3-二甲基-2,3-二硝基丁烷反应的研究

以丙酮肟为原料,在改性TS-1(钛硅分子筛)催化剂催化下,可用H2O2氧化偶联合成2,3-二甲基-2,3-二硝基丁烷(DMNB).在此基础上以丙酮为原料,在改性TS-1催化剂催化下,一锅法进行丙酮氨肟化和氧化偶联反应可制备收率43.2%的DMNB.该方法简便易操作,操作安全.产物结构经1H NMR,13C NMR表征.     

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.     

Site-selective Suzuki cross-coupling reactions of 2,3-dibromobenzofuran

The Suzuki-Miyaura reaction of 2,3-dibromobenzofuran with two equivalents of boronic acids gave 2,3-diarylbenzofurans. The reaction with one equivalent of arylboronic acids resulted in site-selective formation of 2-aryl-3-bromobenzofurans. 2,3-Diarylbenzofurans containing two different aryl groups were prepared from 2,3-dibromobenzofuran in a one-pot protocol by sequential addition of two different boronic acids.