Reactions of 1,3,4-triphenyl-1,2-dihydrophosphete

In contrast to previously reported reactivity of the tungsten pentacarbonyl complex of a 2-substituted 1,2-dihydrophosphete, which apparently undergoes electrocyclic ring opening to the corresponding 1-phospha-1,3-butadiene and subsequent [4+2] cycloaddition reactions with dienophiles, the reaction chemistry of 1,3,4-triphenyl-1,2-dihydrophosphete is dominated by its nucleophilic nature. Although low to modest yields of cycloadducts are obtained with some dienophiles, the reactions forming these products are apparently stepwise, as indicated by the loss of stereochemistry in the reaction of dimethyl maleate and in the competitive formation of a phosphorus-free dimer in the reaction of N-methylmaleimide. Dimethyl acetylenedicarboxylate affords three major products, each of which incorporates two equivalents of the acetylene, again apparently a result of initial nucleophilic addition of the dihydrophosphete to the “dienophile.” © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:9–19, 1998     

Synthesis of 1,3,4-triphenyl-1H-pyrazolo[3,4-e][1,4]thiazepin-7-one

The reaction of 5-amino-1,3-diphenylpyrazole with benzaldehyde gives 5-benzylideneamino-1,3-diphenylpyrazole, which then undergoes cyclization with mercaptoacetic acid to give 1,3,4-triphenyl-1H-pyrazolo[3,4-e][1,4]thiazepin-7-one.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 464–465, April, 1984.     

Effects of metal coordination on the reactivity of 1,3,4-triphenyl-1,2-dihydrophosphete

Nucleophilicity dominates the reaction chemistry of 1,3,4-triphenyl-1,2-dihydrophosphete even when it is coordinated to electrophilic metal centers, but coordination dramatically alters the course of its reactions. Deoxygenation of carbonyl-containing substrates is effected by both the W(CO)₅ complex, which reductively couples benzaldehyde, and the HgCl₂ complex, which converts benzaldehyde to α,α-dichlorotoluene. Metal coordination appears to decrease the tendency of the dihydrophosphete to undergo electrocyclic ring opening to the corresponding 1-phosphabutadiene, and the HgCl₂ complex reacts with dimethyl acetylenedicarboxylate to afford a cyclopentadienyl ylide containing an intact dihydrophosphete unit. By reducing the nucleophilicity of the dihydrophosphete and/or the availability of the highly nucleophilic uncoordinated dihydrophosphete, coordination to HgCl₂ and W(CO)₅ makes accessible new mechanistic pathways. Dihydrooxaphosphinines, although unavailable through the reactions of the dihydrophosphete, may be synthesized by exploitation of the reactivity of organotitanium metallacycles. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:21–28, 1998     

Synthesis of 2,4,6-triphenyl-1,3,5-triazine

Conclusions A study was made of the cyclotrimerization of benzonitrile in chlorosulfonic acid and the optimum conditions were ascertained for the formation of 2,4,6-triphenyl-1,3,5-triazine.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2105, September, 1972.     

Synthesis and properties of triethylammonium 2,2,5-triphenyl-1,3,2,5-dioxaborataphosphorinane

The reaction of bis(hydroxymethyl)phenylphosphine with isobutyl diphenylborate in the presence of triethylamine leads to the formation of triethylammonium 2,2,5-triphenyl-1,3,2,5-dioxaborataphosphorinane (1). The reaction of compound 1 with electrophilic reagents (O, S, Se, CH₂O, RHal) leads to quaternization of the phosphorus atom, giving the corresponding phosphine oxides, sulfides, and selenides and P,B-containing betaines. In the reactions of compound 1 with amines aminomethylphosphines of the diazaphosphorinane and diazadiphosphacyclooctane series are formed. Ammonium 1,3,2,5-dioxaborataphosphorinanes dissociate in solutions and enter into ion exchange with phosphonium iodides, leading to phosphonium 1,3,2,5-dioxaborataphosphorinanes. The latter, in the case of the aminomethylphosphonium cation, undergo intramolecular rearrangement with the formation of P,B-containing betaines and aminomethylphosphines.Deceased.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1398–1405, June, 1992.     

1，3，4-噻二唑簇合物的合成

根据簇合效应原理,以2-氨基-5-巯基-1,3,4-噻二唑为母体,二溴烷烃或二酰氯为连接体,设计并合成了15个新的2-氨基-5-巯基-1,3,4-噻二唑簇合物,其结构经1H NMR和元素分析表征.     

Synthesis of picryl-substituted 1,3,4-oxadiazoles

A convenient procedure was developed for the synthesis of picryl-substituted 1,3,4-oxadiazoles. The nucleophilic replacement of the nitro group in picroylacylhydrazines under the action of thiophenol was studied. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1583–1585, September, 2000.     

含1,3,4-噁二唑和1,3,4-噻二唑的硫醚类化合物的合成

在KOH作用下,芳甲酰肼1a～1e与CS2环化生成5-芳基-2-巯基-1,3,4-噁二唑(2a～2e);将2a～2e与氯乙酸乙酯反应,生成2-(5-芳基-1,3,4-噁二唑)硫基乙酸乙酯(3a～3e);3a～3e肼解得2-(5-苯基-1,3,4-噁二唑-2-硫基)乙酰肼(4a～4e);4a～4e与芳酰基异硫氰酸酯5a～5d反应得到双酰基氨基硫脲衍生物A1～A19;A1～A19在H2SO4催化下环合得到目标化合物B1～B19;目标化合物的结构经IR,1H NMR,MS,HRMS确证.     

Synthesis of 2,6-di-tert-butylphenols linked to 1,3,4-oxadiazoles and 1,3,4-thiadiazoles

The preparation of a series of analogs of 2,6-di-tert-butylphenol linked to a 1,3,4-oxadiazole or 1,3,4-thiadiazole via an ethylene or methyleneoxy spacer is discussed.     

Synthesis of substituted 1,3,4-oxadiazole derivatives

Monosubstituted oxadiazoles were synthesized by the reaction of hydrazides with triethyl orthoformate. Their reactions with benzoyl chloride gave benzoylcarbohydrazides, which under the action of thionyl chloride were cyclized to the respective 2,5-disubstituted oxadiazoles. 1-Aryl-4-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)-pyrrolidin-2-ones were synthesized from acid hydrazides using carbon disulfide under basic conditions. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 269-272, February, 2009.     

Synthesis of steroidal extranucleo 1,3,4-oxadiazoles

Cholest-5en-3β-ol 1 , 3,3-ethylenedioxy-androst-4-en-17β-ol 2 and 17,17-ethylenedioxy-1,3,5(10)-estratrien-3β-ol 3 were converted into ethyl ester 1a, 2a and 3a by reaction with ethyl chloroacetate in the presence of potassium. The ethyl esters 1a, 2a and 3a on reaction with hydrazine gave hydrazides 1b, 2b and 3b , which on reaction with cyanogen bromide afforded 1,3,4-oxadiazoles 1c, 2c and 3c .     

微波促进下2,5-二取代-1,3,4-(口恶)二唑衍生物的合成

报道了微波促进无溶剂条件下二酰基肼可以良好产率脱水闭环得到2，5-二取代-1，3，4-E二唑衍生物。反应产率受取代基影响较大，苯基取代时产率较高，烷基取代时产率较低；反应产率与所用的无机支持有关，其中以酸性三氧化二铝的效果最佳。此法不仅环境友好且操作安全，避免使用化学脱水剂。     

含有异噁唑的S-三唑[3,4-b]-1,3,4-噻二嗪、咪唑[2,1-b]-1,3,4-噻二唑和咪唑[2,1-b]-1,3,4-噁二唑衍生物的合成

异噁唑衍生物作为一类重要的生物活性物质,其合成一直受到人们的关注,其中德国HMR公司开发研制的新型抗内风湿性关节炎药来氟米特(Leftunomide)已于1998年在美国率先上市,该药还具有很好的免疫调节作用．7H-均三唑[3,4-b]-1,3,4-噻二嗪、咪唑并[2,1-b]噻唑和咪唑并[2,1-b]-1,3,4-噻二唑衍生物均表现出广谱的生物活性．     

Synthesis of branched polynuclear 1,3,4-oxadiazoles

The reaction of 5-substituted mono-and polytetrazoles with heterocyclic acid chlorides and trifluoroacetic acid anhydride gave branched polynuclear 1,3,4-oxadiazole systems. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1432–1437, September, 2008.