含内环化A—Bb,Cc缩聚反应的溶胶—凝胶分配

结合Ａａ－Ｂｂ，Ｃｃ型缩聚反应，给出了溶胶中含内环化的溶胶－凝胶分配公式及凝胶化条件。     

分子内环化对溶胶凝胶分配的影响(Ⅰ)——A_a-B_b型缩聚反应

本文用概率方法推导出包括溶胶中分子内环化反应的溶胶凝胶分配方程。由此方程计算出的理论值同实验值符合很好。     

含引发机制A_2 十A_a型缩聚反应的溶胶-凝胶分配理论

讨论了含引发机制的A_2+A_a型缩聚反应体系,给出了该体系溶胶-凝胶分配公式,凝胶化条件,数量分布函数,并证明了数量分布函数的不变性质.     

含时间变量的凝胶溶胶分配方程及其应用

在Ａａ－Ｂｂ型综聚反应的凝胶溶胶分配（ＧＳＤ）方程中引入相应的聚合反应动力学方程．模拟计算的溶胶分数（Ｓ）对反应程度（Ｐ_Ｂ，Ｐ_Ｂ＇）的关系曲线与实验结果基本吻合．利用含时间的ＧＳＤ方程，解决了非线型缩聚反应交联网络的模拟计算，给出了交联度随时间的变化曲线，也为凝胶点的计算提供了一种方法．     

关于Aa-Bb型缩聚物网络结构的研究——溶胶凝胶分配理论

溶胶凝胶分配理论是在分子水平上表征交联网络结构的有效工具。由Flory等建立和发展起来的这一理论,由于引用了溶胶相无分子内环化反应的假定,特别是在理论推导中将分子内交联反应与分子间的链增长反应对两相分配的贡献未能加以区别,致使理论与实验不符。本文充分考虑了经典理论的这些缺欠,建立了更为符合客观实际的理论模型。同时,用十分简便的方法推导了反应溶胶分数,溶胶反应程度,分子内和分子间总反应程度等量宏观联系的参数方程组。以聚酯为模型化合物的实验研究与本文所得理论结果基本相符。     

A_a－B_b型缩聚反应的0－次和1－次回转半径

Ａ_ａ－Ｂ_ｂ型缩聚反应的０－次和１－次回转半径巴信武，李泽生潘守甫（吉林大学理论化学研究所长春，１３００２３）（吉林大学原子与分子物理研究所）关键词缩聚反应，回转半径，差分方法高分子回转半径是表征高分子尺度的重要物理量，Ｄｏｂｓｏｎ和Ｇｏｒｄｏｎ［１...     

一般的A_aB_b缩聚反应的固化理论——Ⅰ.溶胶分数和凝胶化条件

本文讨论了最一般的A_aB_b缩聚反应,包括A基和A基、B基和B基、以及A基和B基的反应,给出了溶胶-凝胶分配公式和相应的凝胶化条件。     

含内环化与不含内环化固化理论间的对应关系

含内环化与不含内环化固化理论间的对应关系黄旭日，肖兴才，李泽生，孙家，唐敖庆（吉林大学理论化学研究所，长春，１３００２３）关键词内环化，非线性缩聚反应，数量分布函数，高分子矩在研究非线性缩聚反应体系的固化问题时，Ｆｌｏｒｙ和Ｓｔｏｃｋｍａｙｅｒ等［１...     

A_a-B_b(B′)_b型缩聚反应在热固化反应过程中的溶、凝胶分配

Flory、Gordon和唐敖庆从相同的基本假定出发,用不同的几率方法提出了凝胶化理论,统称为经典的凝胶化理论,对A_a-B_b(B′)_b体系,汤心颐等曾研究过其凝胶化范围,但只得到了临界反应程度,我们用经典的统计方法,以甘油和丁二酸酐为模型化合物,研究了溶胶分数与反应程度的关系,并导出了酸/醇摩尔比r_b与r_b′的关系式。     

Sol-Gel Distribution of Polycondensation Reaction

A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycondensation of adipic acid with trimethylol propane in a sto-ichiometric ratio of 0. 8, and the effect of intramolecular cyclization is discussed in detail.     

己二酸—三羟甲基丙烷缩聚反应的理论分析

用唐敖庆等曾得到的含内环化A_a-B_b型缩聚反应的固化理论,对配料比为1.3的己二酸-三羟甲基丙烷缩聚反应实验数据进行了分析,得到的溶胶-凝胶分配曲线与实验结果符合的较好,进一步讨论了内环化对凝胶点的影响,算出了凝胶点以上数均、重均和Z均分子量的理论曲线.     

分子内环化对聚乙烯醇交联体系的影响

以聚乙烯醇(PVA)-戊二醛(GA)体系作为研究对象, 系统地研究了分子内环化对凝胶体系的影响, 为水凝胶体系的网络结构评价奠定了一定的实验基础.     

Palladium‐Catalyzed Chemoselective Intramolecular Cyclization of 2‐Bromoaryl Alkenenitriles

The chemoselectivity in the palladium‐catalyzed intramolecular cyclization of 2‐(o‐bromoaryl)‐alkenenitriles depends on the nature of α‐substitutents. 2‐(o‐Bromoanilino)alkenenitriles attacked the cyano group, followed by the cyano group transposition and hydrolysis, to give o‐(methylamino)benzonitrile. 2‐(o‐Bromobenzyl)alkenenitriles, 2‐(o‐bromophenylthio)alkenenitriles and 2‐(o‐bromophenoxy)‐alkenenitriles attacked the olefinic double bonds and led to l‐vinyl‐2‐indancecarbonitrile, 1,2,3,4‐tetrahydronaphthalene‐2‐carbonitriles, 3,4‐dihydro‐2H‐benzo[b]thiine‐2‐carbonitriles, and 3,4‐dihydro‐2H‐benzo[b]oxine‐2‐carbonitriles. A general mechanism for the palladium‐catalyzed arylations is proposed.     

One Pot Spiropyrazoline Synthesis via Intramolecular Cyclization/Methylation

Regioisomeric spiropyrazolines were synthesized through a tandem intramolecular cyclization/methylation reaction of a functionalized 5,5-disubstituted pyrazoline in one reaction vessel. The 5,5-pyrazolines were constructed through a 1,3-dipolar cycloaddition reaction of aromatic ring containing nitrile imines and a disubstituted geminal alkene. An evaluation of the relative location of the nucleophilic and electrophilic functional groups on the pyrazoline was performed in order to ascertain the best pyrazoline system for the intramolecular cyclization/methylation reaction. Higher spiropyrazoline isolated yields were realized from pyrazolines with the electrophilic ester located further away from the pyrazoline when compared to pyrazolines with a directly bonded ester.     

Synthesis of Highly Substituted N-Hydroxy Piperidine via Intramolecular Reductive Cyclization of 1-Keto-5-ketoxime

Abstract

Diasteroselective synthesis of highly substituted N-hydroxypiperidine was achieved by an intramolecular reductive cyclization of monoxime (2) of the 1,5-diketone (1), generated from 2-(cyclohexylthio)-1-phenylethanone and arylaldehyde, using NaBH₃CN. The major product N-hydroxypiperidine (3) has been found to be racemate of a single diastereomer.     

Studies of Intramolecular Cyclization of 4-Arylpyridines. II Syntheses of Condensed Tricyclic Pyridines

A convenient method for the synthesis of condensed tricyclic pyridines using intramolecular cyclization of 4-arylpyridines is reported. The tricyclic compounds, 2-azafluorenone (9), 2-azafluorenone (10), 2-azafluorenol (11), lactones 12 and 13, and anhydride 14 have been prepared.     

分子内Friedel-Crafts环化反应在苯并环状物合成中的应用

Friedel-Crafts反应是有机合成中最有用的反应之一,它的应用范围十分广泛.Friedel-Crafts反应也是合成环状化合物的重要途径,尤其分子内的环化反应一直以来受到广泛的关注.对近年来应用分子内Friedel-Crafts环化反应合成苯并环状化合物进行了详细的综述,并对分子内Friedel-Crafts环化反应在有机合成上发展前景作了展望.     

Intramolecular Heck cyclization to the galanthamine-type alkaloids: total synthesis of (±)-lycoramine

A novel approach towards the construction of the galanthamine skeleton was demonstrated by the total synthesis of (±)-lycoramine. The key steps include a Pd-catalyzed intramolecular cyclization to form the seven-membered azepane ring and a spontaneous intramolecular Michael addition to afford the five-membered furan ring. This synthetic route has also been demonstrated to be useful for the preparation of novel derivatives with simplified galanthamine skeletons.