一步法合成2,4-二硝基苯甲醚

以1-氯-2,4-二硝基苯（CDNB）为原料,不使用相转移催化剂,用KOH溶液为反应介质,一步合成了2,4-二硝基苯甲醚,其结构经¹H NMR, FT-IR和元素分析确证。最佳反应条件为：CDNB 0.20 mol, 30%KOH溶液为反应介质,甲醇100 mL,于55 ℃反应60 min,收率96.5%,纯度99.8%。     

2,4-二硝基氯苯碱性水解胶团催化的活化能

研究了阳离子表面活性剂氯化十六烷基吡啶(CPC)和十六烷基三甲基氯化铵(CTAC)胶团对2,4-二硝基氯苯(DNCB)碱性水解的催化作用和小分子极性有机物丁醇的加入对该反应的影响,计算了反应活化能.结果表明:(1)CPC和CTAC胶团对DNCB碱性水解都有明显的催化作用;(2)加入少量叔丁醇略有利于提高催化效果;(3)在CPC和CTAC胶团溶液中DNCB碱性水解反应的活化能约为49kJ/mol,比纯水中的91kJ/mol低得多,说明反应机制可能存在差异.     

The growth and characterization of 2,4-dinitro phenyl hydrazone of benzophenone and mixed crystals

Good quality benzophenone (BP) crystals were grown by solution technique using CHCl₃ as solvent by adopting slow evaporation method at room temperature. The grown crystals were subjected to various characterization studies to analyze its purity and applications. The condensation product 2,4-dinitro phenyl hydrazone of benzophenone (DNPBP) was prepared by adopting standard procedure. Then mixed crystal of BP and DNPBP was also grown by solution growth. Both the condensation product and mixed crystals were characterized by UV, FTIR, ¹H NMR spectra. Thermal (TG and DTA) studies have proved to be very useful techniques not only to study the thermal properties of BP, DNPBP and mixed crystal but also to study their purity. Second harmonic generation (SHG) efficiency of the grown crystals was determined.     

Synthese und reaktionen von 1-germcyclohexa-2,4-dienen und 1-germacyclohexa-2,4-dien-eisentricarbonylen

1,1-Diakyl(aryl)4-alkyl(aryl)-4-methoxy-1-germacyclohexa-2,5-dienes undergo ether cleavage with sodium in n-pentane or liquid ammonia. Hydrolysis of the resulting sodium salts yields the 1,1-dialkyl(aryl)-4-alkyl(aryl)-1-germacyclohexa-2,4-dienes. Reduction of 1-chloro-4-methoxy-1-germacyclohexa-2,5-dienes with LiAlH₄ can be directed to give the 1H-1-germacyclohexa-2,4-dienes with ether cleavage.The 1H-1-germacyclohexadienes are chlorinated by PCl₅ and brominated by N-bromosuccinimide to the 1-chloro- or 1-bromo-1-germacyclohexa-2,4-dienes, respectively. 1,1-Diethyl-4-phenyl-4-methoxy-1-germacyclohexa-2,5-diene reacts with PCl₃ with ether cleavage and formation of the 6-chloro-1-germacyclohexa-2,4-diene. Ether cleavage is also possible with BCl₃, the 1-phenyl-1-chloro-4R-4-methoxy-1-germacyclohexa-2,5-dienes are transformed into the 1-phenyl-1,6-dichloro-4R-1-germacyclohexa-2,4-dienes.The Fe(CO)₃ complexes of 1,1-dialkyl(aryl)-1-germacyclohexa-2,4-dienes were synthesized.     

Ein neuer Zugang zu 2,6,6-Trimethylcyclohexa-2,4-dienon aus 4-Oxoisophoron

A New Access to 2,6,6-Trimethylcyclohexa-2,4-dienone from 4-Oxoisophorone 2,6,6-Trimethylcyclohexa-2,4-dienone ( 1 ), a versatile starting material for the preparation of some carotenoids and several natural products, was efficiently (73% yield) prepared from oxoisophorone 3 . After conversion of 3 to the alcohol 4 or the acetate 5 , H₂O was eliminated ( 4→1 ) under acidic distillative conditions, whereas AcOH could be eliminated ( 5→l ) under Pd(O) catalysis.     

Methyl triphenylphosphonium peroxydisulfate (MTPPP): A mild and inexpensive reagent for the cleavage of oximes,penylhydrazones and 2,4-dinitro phenylhydrazones to the corresponding carbonyl compounds under non-aqueous conditions

Methyltriphenylphosphonium peroxydisulfate (MTPPP) was synthesized by treating methyltriphenylphosphonium bromide with potassium peroxydisulfate in aqueous solution. This reagent was used as a suitable and efficient reagent for the cleavage of oximes, phenylhydrazones and 2,4-dinitro phenylhydrazones to their corresponding carbonyl compounds under non-aqueous condition.     

L-Proline-Catalyzed Synthesis of Novel 5-(1H-Indol-3-yl-methylene)-thiazolidine-2,4-dione Derivatives as Potential Antihyperglycemic Agents

Knoevenagel condensation between indole-3-aldehyde 1 and an active methylene group containing 2,4-thiazolidinedione 2 in refluxing toluene using L-proline as a catalyst yielded 3, which on alkylation using 2 equivalents of alkylating agent under phase-transfer-catalyzed (PTC) conditions using K₂CO₃ as a base in dimethylformamide gave N,N^I-symmetrically disubstituted 5-(1H-indol-3ylmethylene)-thiazolidine-2,4-diones 4. Alternately, 4 can be synthesized by condensing 5 and 6 in a single step. Using this synthetic strategy, N,N^I-unsymmetricallydisubstituted derivatives 9a–f were prepared either by condensing 6 with N-substituted-2,4-thiazolidinedione 5 to obtain 7 followed by alkylation under PTC conditions or condensing 6 with N-unsubstituted- 2,4-thiazolidinedione 2 to yield 8 followed by alkylation under PTC conditions. The latter are the dehydro analogs of the dihydro-N-substituted-5-(1H-indol-3-yl-methylene)-thiazolidine-2,4-diones, which are potential antihyperglycemic agents.

A Synthesis of Phosphorylated 2,4-Dioxothiazolidine Derivatives

Abstract

The zwitterionic 1:1 intermediates generated from trialkyl phosphites and dialkyl acetylenedicarboxylates are trapped by 2,4-thiazolidinedione and 5-arylidene- 2,4-thiazolidinediones to produce dialkyl 2-(2,4-dioxothiazolidin-3-yl)-3-(dialkoxyphosphoryl) succinates and dialkyl 2-(5-arylidene-2,4-dioxothiazolidin-3-yl)-3-(dialkoxyphosphoryl) succinates in good yields.

GRAPHICAL ABSTRACT     

Gold-catalyzed deoxygenative nazarov cyclization of 2,4-dien-1-als for stereoselective synthesis of highly substituted cyclopentenes

Treatment of 2,4-dien-1-als with allylsilanes and PPh(3)AuSbF(6) (3 mol %) led to formation of 1,4-bis(allyl)cyclopentenyl products; this gold catalyst is superior to commonly used Lewis acids according to catalyst screening. Such gold-catalyzed deoxygenative cyclizations are compatible with various oxygen-, amine-, sulfur-, hydrogen-, and carbon-based nucleophiles. The value of this new catalysis is demonstrated by the diverse annulations of 2,4-dien-1-als with electron-rich alkenes and arenes, providing an easy access to complicated cyclopentenyl frameworks. Structural analysis of annulation products reveals evidence for the participation of Nazarov cyclization. This deoxygenative cyclization is extensible to a tandem intramolecular cyclization/nucleophilic addition cascade, giving polycyclic carbo- or oxacyclic compounds with controlled stereochemistry. This new gold catalysis is applied to a short synthesis of natural compounds of the brazilane family, including brazilane, O-trimethyl-, and O-tetramethyl brazilane.     

Reaction of 3,4,6-trioxoalkanoic acid esters with 2,4-dinitrophenylhydrazine

Methyl 3,4,6-trioxoalkanoates (3,4-dihydroxy-6-oxo-2,4-alkadienoates) reacted with 2,4-dinitrophenylhydrazine to give methyl 3,6-bis[(2,4-dinitrophenyl)hydrazinylidene]-4-oxoalkanoates or methyl {5-alkyl-2-hydroxy-1-(2,4-dinitroanilino)-3-oxo-2,3-dihydro-1H-pyrrol-2-yl }acetates. Alkyl 3,6-bis[(2,4-dinitrophenyl) hydrazinylidene]-4-oxoalkanoates were also synthesized by reaction of disodium 1-alkoxy-1,6-dioxoalka-2,4-diene-3,4-diolates with 2,4-dinitrophenylhydrazine.     

Nitro derivatives of pyrrolo[3,2-<Emphasis Type="Italic">d</Emphasis>]pyrimidine-2,4-diones: Synthesis of amines and new polynuclear heterocycles based thereon

The nitration of 1,3-dimethylpyrrolo[3,2-d]pyrimidine-2,4-diones under different conditions led to the formation of their 6(7)-mono- and 6,7-dinitro derivatives which were reduced to the corresponding amines. The latter reacted with α- and β-dicarbonyl compounds, as well as with ortho-quinones to give a number of new polycyclic heteroaromatic systems.     

Metal-catalyzed chemoselective cycloisomerization of cis-2,4-dien-1-als to 3-cyclopentenones and 4-alkylidene-3,4-dihydro-2H-pyrans

[reaction: see text] PtCl(2) (5 mol %) catalyst effected cycloisomerization of cis-2,4-dien-1-al (1) to 3-cyclopentenone (3) efficiently in hot toluene. In the presence of p-TSA, this PtCl(2) catalysis gave 2-cyclopentenone (5) exclusively because of the secondary isomerization reaction. Although the 1-2 equilibrium state greatly favors aldehyde (1), PdCl(2)(PhCN)(2) (5 mol %) catalyzed cycloisomerization of aldehyde (1) to 4,6,7,8-tetrahydro-3H-isochromene (4) smoothly in hot toluene. A plausible mechanism is proposed on the basis of reaction observation and isotope-labeled experiment.     

Thiazolidine-2,4-dione in benzoylation reaction

Chemistry of Heterocyclic Compounds - The direction of the benzoylation reaction of thiazolidine-2,4-dione under the conditions of basic and general acid catalysis was studied. It was shown that...     

Picryl derivatives of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one

Treatment of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one ( 1 ) with picryl fluoride (PkF) in 1-methyl-2-pyrrolidinone (NMP) gave a mixture of a monopicryl and a dipicryl derivative of 1 in a ratio of 2 :1 , respectively, regardless of the initial concentrations of 1 and PkF. The products were identified as 5-nitro-2-picryl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 2 ) by X-ray crystallography and 5-nitro-2,4-dipicryl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 4 ) by ¹⁵N labeling experiments.     

N-Arylation of nitrogen heterocycles with 2,4-difluoroiodobenzene

Arylation reactions of NH-heterocycles [specifically, pyrazole, 3-(trifluoromethyl)pyrazole, imidazole and pyrrole] with 2,4-difluoroiodobenzene in the absence and presence of copper catalysis are described. The combination of fluoro and iodo substituents in the same aryl substrate has facilitated both S_NAr reactions at the C-F bonds and copper-catalysed Ullmann-type coupling reactions at the C-I bond. Products arising from regioselective reactions and multiple substitutions have been isolated, providing a range of new N-arylated pyrazole, imidazole and pyrrole derivatives.     

3-Methylidene-2,4-dioxo-4-pentafluorophenylbutanoates in the Synthesis of Heterocycles

3-Ethoxy- and 3-arylaminomethylidene-2,4-dioxo-4-pentafluorophenylbutanoates undergo cyclization by the action of hydrazine hydrate and phenylhydrazine to give ethyl 4-pentafluorobenzoylpyrazole-5-carboxylates. The reaction of 3-ethoxymethylidene-2,4-dioxo-4-pentafluorophenylbutanoate with o-phenylene-diamine leads to formation of 3-[2-(2-aminophenylamino)-1-pentafluorobenzoylethenyl]-1,2-dihydroquinoxa-lin-2-one. 3-Arylaminomethylidene-2,4-dioxo-4-pentafluorophenylbutanoates react with o-phenylenediamine to afford 3-(1-aryl-5,6,7,8-tetrafluoro-4-oxo-1,4-dihydroquinolin-3-yl)-1,2-dihydroquinoxalin-2-ones and/or 3-(2-arylamino-1-pentafluorobenzoylethenyl)-1,2-dihydroquinoxalin-2-ones.     

Synthesis of 2,4-diphenyl-1H-pyrrol-1-amine derivatives

The direction of the reaction of 4-bromo-1,3-diphenyl-2-buten-1-one (γ-bromodypnone) with hydrazines depends on the nature of the substituent they contain. Reaction with 1-methylhydrazinium hydrosulfate gives 1-methyl-3,5-diphenylpyridazin-1-ium bromide but carboxylic acid hydrazides give N-(2,4-diphenyl-1H-pyrrol-1-yl)carboxylic acid amides. γ-Bromodypnone and phenylhydrazine give both 1,3,5-triphenyl-1,4-dihydropyridazine and N,2,4-triphenyl-1H-pyrrol-1-amine (15%). 1-(2,4-Dinitrophenyl)hydrazine gives the 2,4-dinitrophenylhydrazone of (Z)-4-bromo-1,3-diphenyl-2-buten-1-one. Condensation of 2,4-diphenyl-1H-pyrrol-1-amine with aromatic aldehydes readily leads to N-(arylmethylidene)-2,4-diphenyl-1H-pyrrol-1-amines and alkylation with methyl iodide gives N,N-dimethyl-2,4-diphenyl-1H-pyrrol-1-amine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–414, March, 2009.     

2,4-dihydroxyquinoline derivatives

Instead of the expected 2,4-dihydroxy-3-quinolyl-3-butanol, the product of its cyclization in the form of the angular isomer-2-methyl-5-hydroxypyrano[3,2-c]quinoline — is obtained in the reduction of 2,4-dihydroxy-3-quinolyl-3-butanone with aluminum, isopropoxide. Some transformations of 2,4-dihydroxy-3-(3-chlorocrotyl)quinoline were investigated.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 836–838, June, 1973.     

Synthesis and bioactivity of novel strobilurin derivatives containing the pyrrolidine-2,4-dione moiety简

（E）-Methyl-2-（2-（bromomethyl）phenyl）-3-methoxyacrylate was reacted with substituted 1-acetylpyr-rolidine-2,4-diones and 3-（1-（hydroxylamino）ethylidene）pyrrolidine-2,4-diones respectively to synthesize two series of/%methoxyacrylate derivatives containing the pyrrolidine-2,4-dione moiety. The structures of the targeted compounds were confirmed by IR, 1H NMR, 13C NMR, MS and elemental analysis. The fungicidal activity against Rhizoctonia solani, Botrytis cinerea and Fusarium graminearum was evaluated. The bioassay results demonstrated that these compounds showed visible fungicidal activity.     

Fluorine-containing 3-arylhydrazono-2,4-dioxobutanoates in reactions with difunctional nucleophiles

3-Arylhydrazono-4-polyfluoroalkyl-2,4-dioxobutanoates reacted with hydrazines to give ethyl 4-aryldiazeno-3-polyfluoroalkyl-1H-pyrazole-5-carboxylates, while analogous reactions of ethyl 3-arylhydrazono-4-pentafluorophenyl-2,4-dioxobutanoates resulted in the formation of 4-aryldiazeno-3-pentafluorophenyl-1,2-dihydropyridazine-5,6-diones or 6-aryl-7,8,9,10-tetrafluoro-2-phenyl-2,4a,6,10b-tetradropyridazo[4,3-c]cinnoline-3,4-diones, depending on the conditions. Cyclocondensation of ethyl 3-arylhydrazono-4-polyfluoroalkyl(or pentafluorophenyl)-2,4-dioxobutanoates with ethylenediamine led to 3-[1-arylhydrazono-2-oxo-2-polyfluoroalkyl(or pentafluorophenyl)ethyl]-5,6-dihydropyrazin-2(1H)-ones, and 3-[1-arylhydrazono-2-oxo-2-polyfluoroalkyl(pentafluorophenyl)ethyl]benzoxazin-2-ones were formed in the condensation with o-aminophenol. Pentafluorophenyl-substituted heterocycles were found to undergo intramolecular ring closure to give 3-hetaryl-substituted 1-aryl-5,6,7,8-tetrafluoro-1,4-dihydrocinnolin-4-ones. The reactions of ethyl 3-arylhydrazono-4-pentafluorophenyl-2,4-dioxobutanoates with o-aminobenzenethiol gave 3-[7-(2-aminophenylsulfanyl)-1-aryl-5,6,8-trifluoro-4-oxo-1,4-dihydrocinnolin-3-yl]benzothiazin-2-ones; 8a-hydroxy-11,12,13,14-tetrafluoro-10-(4-methoxyphenyl)-2,3,4,5,6,7,8a,10-octahydropyrazino[1′,2′:4,5][1,4]diazepino[6,7-c]cinnolin-8-one was isolated in the condensation of ethyl 3-(4-methoxyphenylhydrazono)-4-pentafluorophenyl-2,4-dioxobutanoate with N-(2-aminoethyl)ethane-1,2-diamine.