3-丙酰基-2,5-二芳基-1,3,4-噁唑啉类化合物的合成

3-丙酰基-2;5-二芳基-1;3;4-噁唑啉类化合物的合成;噁唑啉;衍生物;合成;结构表征     

2-芳基-3-N-丙酰基-5-(2-溴-4-氟苯基)-1，3，4噁二唑啉类衍生物的合成及抗菌活性

2-芳基-3-N-丙酰基-5-(2-溴-4-氟苯基)-1;3;4噁二唑啉类衍生物的合成及抗菌活性;噁二唑啉衍生物;合成;结构表征;抑菌活性     

2,5-二取代-1,3,4-噻二唑衍生物的合成与表征

苯并噁唑啉酮和1,3,4-噻二唑衍生物具有多种生物活性,制备含有苯并噁唑啉酮结构的1,3,4-噻二唑衍生物非常有意义。本文以邻氨基苯酚和尿素为初始原料,经多步合成反应,制备了10个新的2-(芳甲酰氨基)-5-(2-苯并噁唑啉酮-3-甲基)-1,3,4-噻二唑化合物(7a～7j),并利用IR、1H NMR和元素分析对其结构进行了表征。     

Zn/Y双金属接力催化:一锅法分子内环异构化/分子间阿尔德-烯反应构建α-羟基酰胺噁唑衍生物

报道了一种新型的Zn/Y双金属接力催化的串联反应,该方法通过Zn(OTf)2和Y(OTf)3接力催化,一锅法进行分子内环异构化/分子间阿尔德-烯反应构建α-羟基酰胺噁唑衍生物.产物的形成主要是由Zn(OTf)2活化炔丙基酰胺的叁键发生分子内的环化反应构建噁唑啉中间体,由Y(OTf)3催化1-苄基吲哚啉-2,3-二酮类化合物,继而由噁唑啉中间体与1-苄基吲哚啉-2,3-二酮类化合物发生分子间阿尔德-烯反应,实现了α-羟基酰胺噁唑衍生物的合成.优化部分的对比实验证实,Zn(OTf)2和Y(OTf)3的存在对于该串联反应都是必须条件.所有反应都是将各反应物和试剂一次性加入,在空气氛围下100℃加热进行反应.该方法反应条件简单、原子经济性高、官能团兼容性好,对噁唑衍生物合成具有重要的意义.     

异噁唑啉酮的不对称芳基化反应

在手性磷酸的作用下,实现了异噁唑啉酮和对苯醌单亚胺的不对称芳基化反应,以高收率和高对映选择性构建了4-芳基异噁唑啉酮衍生物。对其中一个产物进行单晶培养,确定了绝对构型。      

由α-氰基肉桂酸乙酯/N-溴代苯甲酰胺合成2-噁唑啉衍生物

作为重要的杂环化合物,合成新的2-噁唑啉衍生物以及发展其新的合成方法具有重要意义,为此以α-氰基肉桂酸乙酯衍生物为底物,以N-溴苯甲酰胺为反应试剂,在无水碳酸钠(相对于底物3为110%摩尔分数)促进下,在丙酮溶剂中,室温下,建立了合成相应2-噁唑啉衍生物的新方法,共合成了11个新化合物,其结构由核磁共振波谱仪(~1H NMR,~(13)C NMR)和高分辨质谱(HRMS)确认。结果显示,各种α-氰基肉桂酸乙酯衍生物(3a~3k)可被顺利的转化成相应的2-噁唑啉衍生物(5a~5k)。在室温下,丙酮作溶剂,以Na_2CO_3为促进剂时,相应产物的最高收率可达90%。不仅α-氰基肉桂酸乙酯衍生物(3)可被用作该反应的底物,而且α-乙氧甲酰基肉桂酸乙酯(6)也适用于该反应。实验结果还证明,除了N-溴代苯甲酰胺外,N-溴代对硝基苯甲酰胺(8)及N-溴代乙酰胺(9)也适用该反应,证明该方法具有广泛的适应性。根据实验结果,提出了可能的反应机理,该机理支持了形成2-噁唑啉衍生物的区域选择性。     

α-氰基肉桂酸乙酯/酰胺/N-溴代丁二酰亚胺三组分合成2-噁唑啉

以α-氰基肉桂酸乙酯衍生物、酰胺和N-溴代丁二酰亚胺(NBS)为原料,在无水碳酸钠促进下,以N,N-二甲基甲酸胺(DMF)为溶剂,室温下建立了三组分合成2-噁唑啉的新体系.在优化条件下,丙酰胺、丙烯酰胺、异丁酰胺和戊酰胺均能与不同结构的α-氰基肉桂酸乙酯衍生物反应,高收率地生成相应的2-噁唑啉(最高收率可达94%),说明该反应具有广泛的适应性.合成了39个新化合物,其结构均由核磁共振氢谱、碳谱和高分辨质谱确证.根据实验结果,提出了该反应的可能机理,该机理有力地支持了形成2-噁唑啉时的区域选择性.     

Zn/Ni双金属接力催化:一锅法分子内环异构化/分子间酰胺化反应构建噁唑衍生物

报道了一种新型的Zn/Ni双金属接力协同催化的串联反应,该方法通过Zn（OTf）₂和Ni（ClO₄）₂·6H₂O协同接力催化,一锅法进行分子内环异构化/分子间酰胺化反应构建噁唑衍生物.产物的形成主要是由Zn（OTf）₂活化炔丙基酰胺的三键,发生分子内的环化反应构建噁唑啉中间体,由Ni（ClO₄）₂·6H₂O催化3-羟基-2-苯甲基-异吲哚啉-1-酮类化合物形成酰亚胺离子,继而由噁唑啉中间体与酰亚胺离子发生分子间酰胺化反应实现了噁唑分子的合成.优化部分的对比实验证实Zn（OTf）₂和Ni（ClO₄）₂·6H₂O的存在对于该串联反应都是必须条件.大体而言,所有反应都是将各反应物和试剂一次性加入,在空气氛围下100℃加热进行反应.含有不同类型给电子取代基、含有不同富电子的芳环、含有不同吸电子取代基的炔丙基酰胺都可以顺利地和3-羟基-2-苯甲基-异吲哚啉-1-酮反应得到相应的噁唑衍生物,相比而言,含有吸电子基团的炔丙基酰胺比含有给电子基团或富电子的炔丙基酰胺所得到的产物的收率要低一些,这可能是因为含有吸电子基团的炔丙基酰胺所得到的噁唑啉中间体活性较低.3-羟基-2-苯基异吲哚啉-1-酮类化合物、3-羟基-2-苯甲基异吲哚啉-1-酮类化合物和3-羟基-2-苯乙基异吲哚啉-1-酮类化合物对反应同样表现出了良好的兼容性.该方法反应条件简单、原子经济性高、官能团兼容性好,对噁唑衍生物合成和酰亚胺离子形成具有重要的意义.     

聚乙二醇支持的异噁唑啉衍生物的液相合成及其晶体结构

通过可溶性聚乙二醇支持的丙烯酸酯与由醛肟原位产生的腈氧化物进行1,3-偶极环加成反应,合成了PEG支持的异噁唑啉衍生物(3);3用甲醇钠-甲醇溶液解脱,高产率(84%～95%)地合成了4个3,5-二取代异噁唑啉衍生物(4a～4d),其结构经1H NMR, IR, EI-MS表征.采用X-射线单晶衍射测定了4d的晶体结构,4d属单斜晶系,C2/c空间群,晶胞参数:a=26.965 5(17)(A), b=9.370 5(6)(A), c=8.946 5(6)(A), α=γ=90°, β=97.226(2) °, V=2 242.6(3)(A)3, Z=8, Dc=1.299 mg·m-3, μ=0.094 mm-1, F(000)=928, R1=0.041 5, wR2=0.106 4.     

3,4-二羟基-2,5-双[2′-(4′-取代噁唑啉)]呋喃的合成及其应用

3;4-二羟基-2;5-双[2′-(4′-取代噁唑啉)]呋喃的合成及其应用;二羟基双 [(取代噁唑啉)]呋喃;双噁唑啉;手性试剂;不对称还原;合成     

One-pot Synthesis of Isoxazolines Using Soluble Polymer-supported Acrylates

An efficient and rapid parallel liquid-phase synthesis of isoxazolines has been reported.The one-pot three-component reaction of polyethylene glycol-supported acrylates, aldehydes and hydroxylamine hydrochloride in the presence of chloramine-T in methanol gave the corresponding PEG-supported isoxazolines, which can be cleaved from the support under mild condition to afford isoxazolines in good yields (＞80%) and high purities (＞86%).     

Hypervalent iodine-mediated interaction of aldoximes with activated alkenes including Baylis-Hillman adducts: a new and efficient method for the preparation of nitrile oxides from aldoximes

Treatment of aldoximes with activated alkenes in the presence of diacetoxy iodobenzene (DIB) afforded isoxazolines in high yields. The method has been applied for the preparation of polyfunctional isoxazolines from Baylis-Hillman adducts.     

Synthesis and new rearrangements of 4-isoxazolin-4,5-dicarboxylic acid derivatives

Acyclic nitrones react with dimethyl acetylenedicarboxylate (DMAD) to give stable isoxazolines, from which the ones that contain electron-donating aromatic rings at the C3 position (R¹) were shown to undergo unprecedented fragmentation at room temperature, giving the R¹-aldehyde and inseparable product mixtures, probably due to the formation of highly reactive species such as iminocarbenes. Attempts to convert the isoxazolines to the corresponding stable azomethine ylides, by refluxing in toluene, again led to the same product mixtures as above (e.g., the room temperature decomposition). Isoxazolines when reacted with methoxide at room temperature afforded highly functionalised diastereomeric mixtures. Also, isoxazolines, when reacted with propylamine, gave the corresponding amides regioselectively, all of which were more stable than the parent isoxazolines.     

Facile synthesis of carbohydrate-integrated isoxazolines through tandem [4+1] cycloaddition and rearrangement of 2-nitroglycals

Carbohydrate-integrated isoxazolines were synthesized from 2-nitroglycals and sulfur ylides, with the aid of 1-phenylthiourea catalyst. The reactions proceeded via [4+1] annulations and upon subsequent rearrangement, afforded the corresponding isoxazolines in high yields with excellent diastereoselectivities (up to 95% de).     

One-pot Synthesis of Isoxazolines Using Soluble Polymer-supported Acrylate

An eficient liquid-phase synthesis of isoxazolines through a 1,3-dipolar cycloaddition is described.Soluble polymer-supported acrylate reacted with nitrile oxides generated in-situ,followed by cleavage from the support giving corresponding isoxazolines in high yields and excellent purities.     

1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with nitrile oxides and nitrones

1,3-Dipolar cycloadditions of 2-thio-3-chloroacrylamides with nitrile oxides and nitrones is described. A series of novel isoxazolines are isolated from the nitrile oxide cycloadditions, whilst the isoxazolines generated from the nitrone cycloadditions undergo further ring opening to yield piperidines.     

Synthesis and Characterization of Some Novel Higher C,N-Diphenyl Nitrones,Isoxazolines, and Mercaptobenzimidazoles as Oleochemicals

Abstract

Some novel long-chain nitrones, isoxazolines, and (1H-benzo[d]-imidazol-2-ylthio) derivatives were synthesized. Nitrones, N-{4-[2-(tetradecylthio)acetoxy]benzylidene}aniline oxide, and N-[4-(12-oxo-2,5,8,11-tetraoxadocosan-22-yloxy)benzylidene]aniline oxide were prepared via the reaction of β-phenylhydroxylamine with the corresponding aromatic aldehydes. The isoxazolines were prepared from undec-10-en-1-ol and benzonitrile-N-oxide which was generated in situ. The 1H-benzo[d]-imidazol-2-ylthio derivatives were synthesized via the replacement reaction of ω-bromo esters and 2-mercaptobenzimidazole.     

Nitrile oxide cycloaddition routes to 2-(isoxazolyl)-benzoates and 2-(1,2,4-oxadiazol-3-yl)benzoates

Cycloaddition of aromatic nitrile oxides to methyl o-vinylbenzoate produced methyl 2-(3-aryl-2-isoxazolin-5-yl)benzoates; the isoxazolines were converted to methyl 2-(3-arylisoxazol-5-yl)benzoates. Reaction of the nitrile oxide from o-methoxycarbonylbenzohydroximinoyl chloride ( 11 ) with phenylacetylene, styrenes, and aromatic nitriles resulted in methyl 2-(5-phenylisoxazol-3-yl)benzoate, methyl 2-(5-aryl-2-isoxazolin-3-yl)-benzoates ( 15 ), and methyl 2-(5-aryl-1,2,4-oxadiazol-3-yl)benzoates, respectively. The isoxazolines 15 were converted to the corresponding isoxazoles 16 .     

Mo(CO)6-mediated synthesis of calix[4]arenes carrying β-hydroxy ketones or α,β-unsaturated-β-amino ketones

Mo(CO)₆-mediated ring opening reactions of calix[4]arene isoxazolines/isoxazoles provide a new synthetic methodology for calix[4]arenes carrying bifunctional β-hydroxy ketones or α,β-unsaturated-β-amino ketones. Mo(CO)₆ is a highly selective and convenient reagent for the ring opening process of these supramolecular isoxazolines/isoxazoles.     

Acyclic nitronate olefin cycloaddition (ANOC): regio- and stereospecific synthesis of isoxazolines

We report the first demonstrations of intra- and intermolecular acyclic nitronate olefin cycloaddition (ANOC) reactions that enable the highly efficient syntheses of isoxazolines bearing various functional groups. This general approach to accessing γ-lactone fused isoxazolines was hitherto unprecedented. The room temperature transformations reported herein exhibit wide substrate scopes, as evidenced by more than 70 examples, including the generation of five tricyclic isoxazolines. The robustness of this methodology was confirmed by a series of trials that afforded highly functionalized isoxazolines. Both experimental results and density functional theory calculations indicate that these transformations proceed via the in situ formation of acyclic nitronates together with concerted [3+2] cycloaddition and tert-butyloxy group elimination processes to give regio- and stereospecificity.

A novel acyclic nitronate olefin cycloaddition (ANOC) reaction was successfully established, which enabled facile construction of various isoxazolines.