氮杂Wittig反应的最近进展

综述了最近几年氮杂Wittig反应的研究进展,包括分子间氮杂Wittig反应、分子内氮杂wittig反应及串联的氮杂Wittig反应。讨论了氮杂Wittig反应在一些含氮杂环、稠杂环及天然产物合成中的应用。     

无溶剂反应在杂环合成中的应用进展

杂环化合物在药物和农药领域具有多种优良的生物活性,其合成方法是目前药物和农药研究的热点领域之一.以绿色合成为主题,介绍了无溶剂杂环有机合成在产率高、选择性好、操作简便、成本低及环境友好等绿色化学方面的优点,综述了近四年无溶剂反应在杂环合成方面研究的最新进展.     

五元氮杂环的开环反应研究进展

综述了近年来各种五元氮杂环的开环反应及其在有机合成中的应用。杂环化合物在有机合成中的作用越来越重要,五元氮杂环是其中最重要的一部分,其开环反应可以用来合成某些用其它方法难以合成的多官能团化合物,或通过开环和修饰合成其它环状化合物,还可以作为保护基以及研究仿生合成领域中各类复杂的生化反应等。     

杂氮钛三环的合成

本文报道了具有N→Ti配位键的2,8,9-三氧杂-5-氮杂-1-钛杂三环[3.3.3.0~(1,5)]十一碳烷的合成及其性质。共制得六个新的化合物。研究了制备它们的最佳条件及化学稳定性。     

手征性杂氮钛三环化合物的合成

杂氮钛三环(titatrane)(Ⅰ)是一类具有五配体特殊结构的杂环化合物,由于对其合成工作研究的不多,所以这类化合物的一些性质还鲜为人知。我们对杂氮钛三环的合成方法做了改进,将手性中心引入到这类化合物中,合成了下列结构图中(Ⅱ)所示的具有手性的杂氮钛三环。     

多氮杂环类化合物的设计与合成

以1-咪唑基甲醛为原料,经Aldol缩合反应、Michael加成和关环反应,用室温无溶剂研磨的方法,设计并合成了3个多氮杂环类化合物,其结构经1H NMR和13C NMR表征.     

环链转移反应及其在合成杂环化合物中的应用

概括了环链转移反应的类型、机理,同时综述了环链转移反应在合成取代杂环化合物中的应用。     

多组分反应合成杂环化合物研究进展

利用多组分反应合成结构复杂多样的杂环化合物,在有机合成领域具有广阔的应用前景和研究价值.本文综述了近年来多组分反应在五元杂环、六元杂环、多元杂环合成中的研究进展,同时对杂环化合物的绿色合成方法做出展望.     

高张力笼形氮杂环化合物的合成

以六苄基六氮杂异伍兹烷(HBIW)为母体,Pd(OH)₂/C为催化剂,在温和条件下,通过选择性催化氢解脱苄,使部分或全部苄基被其它官能团(如CH₃O-,C₂H₅-,CHO-)取代,合成了4种N-取代六氮杂异伍兹烷,并鉴定了它们的结构.这些化合物都是高张力的笼形氮杂环化合物,且均可作为合成六硝基六氮杂异伍兹烷(HNIW)的前体,而HNIW是当今最引人注目和最有军用前景的高能量密度化合物(HEDC).     

某些氮杂环烷衍生物的合成

多氮杂环多羧酸及其氮取代化合物因其特殊的螯合能力近年来得到了日益广泛的研究,多氮杂环烷多乙酸的合成及其应用研究报道较多[1～3],而多氮杂环多丙酸及氮上带3个碳原子以上取代基的化合物研究较少,随着氮原子上碳链的增长,此类化合物作为配体其硬度下降,有助于分离某些金属离子.我们以Cyelen.4HCl及Cyclam为原料以LiOH为碱在水溶液中与氯丙酸反应合成了化合物Ⅰ,Ⅱ,用Cyclen和Cyclam为原料与丙烯腈回流合成了化合物Ⅲ,Ⅳ.     

An efficient one-pot synthesis of pyrrolines and tetrahydropyridines from their chloro-precursors via in situ aza-Wittig reaction

A simple and efficient method for synthesizing pyrrolines and tetrahydropyridines via an intramolecular aza-Wittig reaction has been achieved by microwave irradiation of the corresponding chloro-alkane derivatives in the presence of tertiary phosphite and sodium azide. The in situ formation of the alkyl azides makes this a facile and safe method for aza-Wittig reactions.     

One-pot and regioselective synthesis of polysubstituted 3,4-dihydroquinazolines and 4,5-dihydro-3H-1,4-benzodiazepin-3-ones by sequential Ugi/Staudinger/aza-Wittig reaction

An efficient one-pot and regioselective synthesis of 3,4-dihydroquinazolines and 4,5-dihydro-3H-1,4-benzodiazepin-3-ones by Ugi/Staudinger/aza-Wittig sequence has been developed. The Ugi reactions of 2-azidobenzylamines, aldehydes, acids (or α-keto acids) and isocyanides produced the azide intermediates, which were then treated with tributylphosphine or triphenylphosphine to give polysubstituted 3,4-dihydroquinazolines or 4,5-dihydro-3H-1,4-benzodiazepin-3-ones in moderate to good yields by tandem Standinger/aza-Wittig reactions.     

Synthesis of new 1,2,4-oxadiazolidin-5-ylthiophenes and thienopyrimidine derivatives by aza-Wittig reaction using a thienyl carbodiimide

Azidation of aminothiophene derivative 1 afforded the corresponding azido derivative 2.The latter reacted with triphenylphosphine to afford iminophosphorane derivatives 3.Reacting 3 with phenylisocyanate gave the highly reactive carbodiimide intermediate 4,which was reacted with different nitrones to afford new l,2,4-oxadiazolidin-5-ylidene-aminothiophenes 5a-c. Treatment of 4 with absolute EtOH at room temperature gave methyleneamino-5-(methylthio)thiophene 7,(methylthio)-3-(3- phenylureidothiophene)-2-carboxylate 8 or thienopyrimidine 9 and 10 at refluxing temperature.Finally reaction of carbodiimide intermediate 4 with different secondary amines gave the new thienopyrimidines 11a-c.     

First total synthesis of two new heterocyclic compounds:Bretschneiderazines A and B

Facile synthesis of the two new natural heterocyclic compounds bretschneiderazines A（2） and B（3）,isolated from an extract of the stems of Bretschneidera sinensis,is reported.We employed the cyclization reaction of benzamide by directed lithiation and sequential treatment with sulfur and phosgene as key steps.All new compounds have been fully characterized by means of IR,¹H NMR,¹³C NMR,and HRMS.     

Tandem reaction of heterocyclic ketene aminals with diazoesters: Synthesis of pyrimidopyrrolidone derivatives

A tandem reaction of heterocyclic ketene aminals (HKAs) with diazoesters in the presence of a Cu catalyst is demonstrated for the efficient synthesis of pyrimidopyrrolidone derivatives. The reaction shows a broad substrate scope and excellent functional group tolerance. Our method provides rapid access to diverse pyrimidopyrrolidones in moderate to excellent yields under mild reaction conditions.     

The Mitsunobu reaction in the chemistry of nitrogen-containing heterocyclic compounds. The formation of heterocyclic systems (review)

Methods for the design of nitrogen-containing heterocyclic systems involving the formation of C-N bonds under the conditions of the Mitsunobu reaction are discussed. Dedicated to Afanasi Andreevich Akhrem on his 95th birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 347–385, March, 2008.     

Seven- and eight-membered heterocyclic biaryl synthesis through a metal-free oxidative coupling reaction

A metal-free intramolecular biaryl coupling mediated by DDQ and BF₃·OEt₂ was developed. The reaction proceeds smoothly at room temperature to give seven- and eight-membered heterocyclic biaryl compounds in up to 95% yields. Only 1 equiv of DDQ sufficed for the reaction, obviating the use of a large excess of oxidants and undesired chlorination pathway in metal-mediated process.     

Biocatalytic promiscuity: lipase-catalyzed asymmetric aldol reaction of heterocyclic ketones with aldehydes

The new promiscuous activity of lipase from porcine pancreas, type II (PPL II), has been observed to catalyze the direct asymmetric aldol reaction of heterocyclic ketones with aromatic aldehydes. PPL II showed favorable catalytic activity and had a good adaptability to different substrates in the reaction. The enantioselectivities of up to 87% ee and diastereoselectivities of up to 83:17 (anti/syn) were achieved. It is interesting that PPL II possesses the function of aldolase in organic solvents.     

Three-component cascade reaction synthesis of polycyclic 1,4-dihydropyridine derivatives in water

An efficient and straightforward synthesis of polycyclic 1,4-dihydropyridine derivatives has been developed by reacting heterocyclic ketene aminals (HKAs) with 1,3-cyclohexanedione derivatives and a number of substituted salicylaldehyde, respectively, via three-component cascade reactions in water. This strategy provides an efficient and environmentally friendly approach for easy access to various new fused polycyclic 1,4-dihydropyridine derivatives without the need of organic solvents in moderate to good yields.     

Efficient synthesis of functionalized pyrimidones via microwave-accelerated rearrangement reaction

An efficient synthesis of functionalized pyrimidones via microwave-accelerated rearrangement reaction of amidoxime DMAD adducts is described. In most cases, the pyrimidone formation was furnished in reasonable yield after 2 min of microwave irradiation.