1,3偶极环加成合成芳基氮氧螺环化合物的研究

螺环化合物是一类天然产物和药物中常见的杂环化合物,它们具有多种生物活性,在医学上其抗菌、抗病毒、消炎等生物活性非常显著,是国内外研究的一个热点。1,3偶极环加成反应是一个重要的有机合成反应,它的应用很广泛,在多种药物中间体的合成中起了至关重要的作用。文章是关于1,3-偶极环加成反应合成一系列新的含氮氧螺杂环化合物的研究。以α-亚甲基-γ-丁内酯作为亲偶极体与自制的腈氧化物偶极体进行1,3-偶极环加成反应合成了9种含氮氧螺杂环化合物,并对得到的新螺杂环化合物进行了红外、核磁共振氢谱、核磁共振碳谱分析。     

Ag2O/PPh3催化合成4-位季碳吡咯烷衍生物

本文报道了以Ag2O/PPh3为催化体系,催化偶氮甲碱叶立德与a-取代的丙烯酰胺之间的1,3-偶极环加成反应构建4-位季碳的吡咯烷衍生物。通过条件优化和底物适应性研究,以大于20︰1的非对映选择性及87%～97%的产率合成了7个4-位季碳吡咯烷类化合物,并且该反应条件温和,催化剂廉价易得。     

1,3偶极环加成合成芳基螺环化合物的研究

螺环化合物是一类天然产物和药物中常见的杂环化合物,它们具有多种生物活性,在医学上其抗菌、抗病毒、消炎等生物活性非常显著,是国内外研究的一个热点。1,3偶极环加成反应是一个重要的有机合成反应,它的应用很广泛,在多种药物中间体的合成中起了至关重要的作用。本文以1,3偶极环加成和点击化学的方法进行了一系列的芳基螺环化合物的合成研究及表征。     

1-苄基-4-（4-甲氧基）-苯基-1，2，3-三唑的合成

采用氯苄和叠氮化钠在乙醇中反应制备了苄叠氮,进而与对甲氧基苯乙炔进行1,3-偶极环加成反应合成了未见报道的1-苄基-4-（4-甲氧基）-苯基-1,2,3-三唑,产率达到了48％,产物结构经NMR和MS确认。     

2-苯基-3,5-二(4-吡啶基)异噁唑啉的合成及生物活性的研究

以硝基苯为起始原料,经还原生成苯基羟胺、再与4-吡啶甲醛反应生成硝酮、与4-乙烯基吡啶发生1,3-偶极环加成反应等3个步骤合成得到未见文献报道的新型四氢异噁唑啉化合物2-苯基-3,5-二(4-吡啶基)异噁唑啉。通过IR、1 HNMR、13 CNMR、HRMS等对该化合物的结构进行了表征。确定优化的1,3-偶极环加成反应条件为:反应温度75℃、溶剂为DMF。并对合成的新型四氢异噁唑啉化合物进行了生物活性测试,发现该化合物对10种病菌均有不同程度的抑制作用,尤其是对苹果轮纹的防效最高,达到了72.9%。表明,2-苯基-3,5-二(4-吡啶基)异啉啉具有一定的生物活性。     

2-叔丁氧羰基-9-乙氧羰基-2,7-二氮杂-螺[4.4]壬烷的合成

报道了2-叔丁氧羰基-9-乙氧羰基-2,7-二氮杂-螺[4.4]壬烷的合成方法,即以甘氨酸乙酯盐酸盐■为起始原料,与丙烯酸乙酯■经迈克尔加成、 Boc保护和分子内迪克曼缩合生成3-乙氧羰基-4-吡咯酮(■)和2-乙氧羰基-3-吡咯酮(■)后,经Krapcho脱羧反应生成N-Boc-3-吡咯酮(■),随后与磷酰乙酸三乙酯经Witting-Horner-Emmons反应生成α,β-不饱和羧酸乙酯(■),再经[1,3]-偶极环加成反应生成螺环双吡咯烷(■),最后经氢解脱去苄基等7步反应得到标题化合物2-叔丁氧羰基-9-乙氧羰基-2,7-二氮杂-螺[4.4]壬烷(TM),总收率为11%,中间体和目标产物结构经~1H NMR和MS确证。     

几种N-亚胺喹唑啉叶立德化合物的制备与表征

以取代邻硝基苯甲醛为初始原料,经3步反应合成了6个新型的N-亚胺喹唑啉叶立德化合物(■),产物经核磁共振氢谱、碳谱、红外光谱和高分辨质谱确证。     

1,3–偶极环加成反应在固化含能黏合剂中的应用

从叠氮化物的1,3–偶极环加成反应和腈氧化物的1,3–偶极环加成反应两个方面,综述了它们分别固化含能黏合剂的研究进展。介绍了叠氮黏合剂与多炔基化合物、端炔基黏合剂与多叠氮化合物2种固化反应,以及腈氧化物的固化反应原理及其在低温固化方面的应用情况。指出了未来腈氧化物研究的3个重点方向:固化剂的理论设计、黏合体系与炸药的作用机理、材料间相容性研究。     

1-取代苄基-4-乙酰基-5-甲基-1,2,3-三唑的合成

以取代溴苄为原料,经取代和1,3-偶极环加成反应,得到1-取代苄基-4-乙酰基-5-甲基-1,2,3-三唑。实验表明,以无水碳酸钾为碱催化剂,乙腈和乙醇等体积混合为反应溶剂,物料配比n（取代苄基叠氮）∶n（乙酰丙酮）=1∶1.2,反应时间约为2 h,产品收率92%。目标化合物的结构得到1H NMR、MS和IR证实。     

1-苄基-5-苯基-1,2,3-三氮唑的合成

以氯化苄和叠氮化钠为原料,通过叠氮化反应,制得叠氮苄,反应收率达到95.2%。苯乙炔和叠氮苄,通过1,3-偶极环加成反应制得1-苄基-5-苯基-1,2,3-三氮唑,收率26%。该反应是原子经济的绿色化学反应。     

3-Functional substituted 4-trifluoromethyl tetrahydrothiophenes via [3 + 2]-cycloaddition reactions

New 4-(trifluoromethyl)tetrahydrothiophenes containing an ester, sulfone, sulfoximine, sulfonamide, or phosphonate moiety at position 3 were synthesized by 1,3-dipolar [3?+?2]-cycloaddition reactions of 3,3,3-trifluoropropene derivatives and thiocarbonyl ylide generated in situ from chloromethyl trimethylsilylmethyl sulfide.     

一锅法制备四氢苯并呋喃衍生物

以取代苯乙酮为起始原料,经由分子碘的卤代,与吡啶成盐得到氮叶里德化合物,再进一步在碱存在下与1,3-环己二酮、取代苯甲醛反应,一锅法高收率制备得到目标化合物,该方法不需提前制备a-卤代苯乙酮或者不饱和羰基化合物,具有操作简便、条件温和、产率较高等特点。目标产物经~1HNMR、~(13)CNMR、IR和MS进行确认。     

Effect of cobalt on the electrical conductive property of epoxy resins

Cobalt acrylate (CoA₂) has been treated with bisphenol‐A and epichlorohydrin to modify epoxy resins. It was cured with p‐acetylbenzilidene triphenyl arsonium ylide. The properties such as epoxide equivalent weight (equiv/100 g), molecular weight, hydrolyzable chlorine content increases whereas hydroxyl content, refractive index decreases in the presence of CoA₂. The cured epoxy resins shows improve electrical conductivity due to the incorporation of CoA₂ with epoxy resins. The influence of complex formation of CoA₂ with either linkage of epoxy resins were investigated by spectroscopy. The decrease in T_g from differential scanning calorimetry support the improve in flexibility. The dispersion of cobalt in epoxy resins matrix was confirmed by scanning electron microscope. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Multicomponent Reactions of Phosphines,Enynedioates and Cinnamaldimines Give γ‐Lactams with a 1,3,5‐Hexatriene Moiety for Facile 6π Electrocyclization: Access to Oxindoles,Isatins and Isoxazolinones

Multicomponent reactions of phosphines, enynedioates and cinnamaldimines generated 3‐phosphorus ylide γ‐lactams having a 1,3,5‐hexatriene moiety with low activation energy barrier for 6π electrocyclization, through initial formation of 1,3‐dipoles from the α(δ′)‐Michael addition of phosphines to enynedioates. The reactive 1,3‐dipoles underwent addition to cinnamaldimines, lactamization, 6π electrocyclization and oxidation to give 3‐phosphorus ylide oxindoles as platform molecules toward isatins and isoxazolinones. The key step, 6π electrocyclization, was further examined by a kinetic and a computational study.

     

An efficient synthesis of stable sulfur-containing phosphoranes derived from 2-mercapto-1-methylimidazole and 2-thiazoline-2-thiol

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of strong SH-acids, such as 2-mercapto-1-methylimidazole and 2-thiazoline-2-thiol. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon–carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

Radical polymerization of n‐butyl methacrylate initiated by stibonium ylide

1,2,3,4‐Tetraphenylcyclopentadiene triphenyl stibonium ylide initiated radical polymerization of n‐butyl methacrylate (n‐BMA) in dioxane at (60 ± 0.2)°C for 90 min under nitrogen atmosphere has been carried out. The system follows nonideal kinetics, i.e., R_p α [ylide]^0.2 [n‐BMA]^1.8. The value of k/k_t and overall energy of activation have been computed as 0.133 × 10^?2 L mol^?1 s^?1, 33 kJ/mol, respectively. The FTIR spectrum shows a band at 1745 cm^?1 due to acrylate group of n‐BMA. The ¹H NMR spectrum shows a peak of two magnetically equivalent protons of methylene group at 2.1 δ ppm. The DSC curve shows glass transition temperature (T_g) as 41°C. The presence of six hyperfine lines in ESR spectrum indicates that the system follows free radical polymerization and the initiation is brought about by phenyl radical. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2457–2463, 2007     

A Straightforward Synthesis of Enantiomerically Pure trans‐2, 5‐Bis(alkyloxymethyl) pyrrolidines by 1, 3‐Dipolar Cycloaddition Reactions of Azomethine Ylides

A new efficient method for the stereoselective preparation of trans‐2,5‐bis(alkyloxymethyl)pyrrolidines ( 7 ) using easily available starting materials is described. The main step of this synthesis is the stereoselective formation of the pyrrolidine ring by the 1,3‐dipolar cycloaddition reaction of an in situ generated azomethine ylide. Both enantiomers of the C₂‐symmetric auxiliaries are prepared separately in a short reaction sequence.     

1,3-Dipolar Cycloadditions of 1,1-Difluoroallene,Nitrones, Nitrile-Oxides and Carbonyl Ylides

The 1,3-dipolar cycloadditions of C,N-diphenylnitrone, C-phenyl-N-methylnitrone, triphenylnitrone, mesitylnitrile oxide and tetracyanocarbonyl ylide with 1,1-difluoroallene (DFA) are reported and discussed with respect to regiochemistry. Each of the dipoles adds exclusively to the C₂—C₃, non-fluorine-substituted π-bond of DFA. The nitrones all undergo regiospecific reactions while mesitylnitrile oxide does not. The results are discussed with respect to FMO theory and other factors which can give rise to regiochemical variation.     

p-acetyl benzylidene triphenylarsonium ylide initiated radical terpolymerization of styrene,acrylonitrile and copper acrylate: synthesis,characterization and properties

Solution terpolymerization of styrene (Sty), acrylonitrile (AN) and copper acrylate (CuA) has been carried out in dimethylformamide at 90°C for 4 h using p-acetyl benzylidene triphenylarsonium ylide as radical initiator. ¹H nuclear magnetic resonance (NMR), IR and elemental analysis have been used to characterized the terpolymer. Analysis of kinetic data indicates the following rate equation: The overall activation energy is 38 kJ mol⁻¹. The composition of terpolymer calculated from NMR and elemental analysis has been used to evaluate reactivity ratios as r₁(Sty) = 5 ± 2 and r₂(AN + CuA) = 0.4 ± 0.02 employing the Finemann–Ross method, which confirms its random origin. The terpolymer was thermally stable up to 2007deg;C.     

Microwave-assisted reactions of α-diazoketones with hetaryl and ferrocenyl thioketones*

Differently substituted hetaryl thioketones react with less reactive diazoketones under microwave (MW) irradiation in toluene solution. After only 2?min, the reactions were complete and, depending on the type of the used diazoketone, α,β-unsaturated ketones, acyl substituted thiiranes or 1,3-oxathioles were obtained as final products. In the case of azibenzil and di(thiophen-2-yl) thioketone, a new type of 1,5-dipolar electrocyclization of the intermediate thiocarbonyl ylide involving a thiophene ring led to a fused sulfur heterocycle. In contrast to hetaryl thioketones, the ferrocenyl analogues decompose under MW irradiation. Alternatively, they react with diazopropanone and 2-diazo-1-phenylethanone in boiling THF in the presence of LiClO₄ to give α,β-unsaturated ketones as sole products. In these cases, the reactions require long reaction times.