N-溴代丁二酰亚胺氧化γ(δ)-内酯合成4(5)-氧代羧酸

以γ(δ)-内酯为原料,N-溴代丁二酰亚胺(NBS)为氧化剂,合成了具有不同碳链长度的4(5)-氧代羧酸,其结构经NMR和MS表征.考察了NBS用量对产率的影响和反应温度对反应时间的影响.较适宜的反应条件为γ(δ)-内酯5 mmol, NBS 6.75 mmol,于40 ℃反应1.5 h～3.5 h,产率53%～97%.     

β-硝基苯乙烯衍生物与丙烯酰胺及N-溴代丁二酰亚胺的区域专一性氨溴加成反应

以β-硝基苯乙烯衍生物为底物,丙烯酰胺和N-溴代丁二酰亚胺(NBS)为氮源和卤素源,建立了碳-碳双键上的选择性氨溴加成反应新体系.以二氯甲烷为溶剂,在没有惰性气体保护及乙醇钠促进下,β-硝基苯乙烯衍生物与丙烯酰胺和NBS于室温反应即可高收率地获得α-氨基-β,β-二溴加成产物,最高收率达83%;以甲醇为溶剂,在无水碳酸钠作用下,β-甲基-β-硝基苯乙烯衍生物也可高收率地获得相应的邻位氨溴加成产物,最高收率达97%.共考察了25种不同结构β-硝基苯乙烯衍生物的氨溴加成反应,结果表明,该反应具有广泛的适应性.采用核磁共振波谱及质谱表征了产物的结构,并提出了可能的反应机理.     

K_2CO_3/Ni(OAc)_2催化下的以苯甲酰胺和N,N-二溴苯甲酰胺为氮溴源的胺溴化反应(英文)

本文报道了一个高效的以苯甲酰胺和N,N-二溴苯甲酰胺为氮溴源的胺溴化反应。这个反应有广泛的底物适应性、很好的产率及较高的非对映选择性。本文报道的胺溴化反应用金属无机盐和碱作为共同催化剂,与作者们以前报道的胺卤化反应不同。     

对NBS反应中低溴浓度的估算

NBS(N-溴代丁二酰亚胺)的应用对烯丙位和苄位上的特殊溴化提供了一个极有用的方法。对于这类反应,NBS的特殊价值是由于分子卤素在双键存在下不能完成取代而给出加成,但NBS却能发生取代反应而双键不受干扰。对于这个反应历程直到     

N-溴代丁二酰亚胺催化水杨醛与麦氏酸反应合成香豆素-3-羧酸

室温条件下、水和乙醇的混合液中,N-溴代丁二酰亚胺(NBS)促进2-羟基苯甲醛与麦氏酸连续发生Knoevenagel缩合反应和分子内环化反应,高产率地合成了一系列的香豆素-3-羧酸.该方法扩展了可用于合成香豆素-3-羧酸的催化剂的种类,同时还具有催化剂廉价易得、反应条件清洁环保、底物适用性广、后处理简单和产物易于纯化等优点.     

乙酰乙酰苯胺类化合物导向的2,2-二溴乙酰苯胺衍生物的合成

以N-溴代丁二酰亚胺(NBS)为溴源,醋酸为催化剂和溶剂,经过活泼亚甲基的两次连续的溴化,羰基的质子化和碳碳键的断裂等过程合成了2,2-二溴乙酰苯胺衍生物.该方法具有操作简便、反应条件温和和高效等特点.所有反应都能以极高的收率得到相应的目标产物.     

碳酸银催化N-氟代二苯磺酰亚胺与丙炔酸衍生物的氢胺化反应

N-氟代二苯磺酰亚胺(NFSI)的胺化反应已成为制备胺类化合物的重要方法,但利用它制备N-烯基磺酰亚胺的方法不多.在磷酸氢二钠存在下,碳酸银和1,10-菲啰啉衍生物共同催化NFSI与丙炔酸酯或丙炔酰胺发生氢胺化反应,高选择性地生成顺式N-烯基二苯磺酰亚胺类化合物,产率为35%～71%.     

硅有机化合物Ⅱ 四(对甲苯基)硅烷的反应

本文报告四(对甲苯基)硅烷的硝化、溴化和氧化反应的结果。当用硝酸铜和醋酸酐在室温硝化时,生成三(对甲基间硝基苯基)对甲苯基硅烷,产率接近定量。当用 N-溴代丁二酰亚胺溴化时,一个甲苯基-硅键发生断裂,生成三(对溴甲苯基)溴硅烷,水解得出相应的硅醇,其中的溴甲基经 Sommlet 反应可以变成醛基。当用铬酸酐和乙酸酐氧化时,得出高熔点的四(对羧苯基)硅烷,并制成其乙酯。     

芳香杂环甲基卤代反应

总结了五元、六元及其它芳香杂环的甲基卤代的制备方法,如甲基呋喃、甲基嗯唑及甲基吡啶的溴化条件等。主要有三种方法：（1）芳香杂环甲基直接以N-溴代丁二酰亚胺（N-Bromosuccinimide,NBS）溴化。（2）以芳香杂环的羟基甲基与三苯基磷和四溴化碳反应。（3）通过预留卤代甲基来生成相应的芳香卤代甲基,如3-氯甲基-1H-吡唑-羧酸乙酯的合成。     

高灵敏荧光法测定盐酸雷尼替丁

基于N-溴代丁二酰亚胺可与盐酸雷尼替丁发生氧化还原反应,剩余的N-溴代丁二酰亚胺能氧化亚甲基蓝,β-环糊精对未参加反应的亚甲基蓝具有荧光增强作用,可使其荧光增强近2倍,通过测定亚甲基蓝的荧光强度间接测定盐酸雷尼替丁的含量,建立了测定盐酸雷尼替丁荧光新方法,体系的最大激发波长为647 nm,最大发射波长为683 nm,线性范围为0.05~1.55 mg/L,检出限为7μg/L,相对标准偏差为0.2%。方法已用于实际样品的测定。     

A one-pot three-component approach to synthesis of novel dihydroxyoxoindeno[1,2-b]pyrrole derivatives

A new class of 2-arylamino-dihydroxyindenopyrroles were prepared by the one-pot multicomponent reaction of ninhydrin, N-methyl-1-(methylthio)-2-nitroethenamine and aromatic amines in EtOH at room temperature. The advantages of this procedure are short reaction times, good to high yields, easy separation of products and good functional group tolerance.     

以国产微晶纤维素膜作固体基质五种多环芳烃的室温磷光法研究

本文考察了10种国产纤维素膜用于多环芳烃固体基质室温磷光(SS-RTP)的可行性。实验表明:MN-C和MN-P两种型号的微晶纤维素膜用于多环芳烃的SS-RTP是适宜的。阴离子交换纤维素膜、CM-纤维素膜和聚酰胺-6膜也能诱导出多环芳烃的RTP来,但其性能逊于前两种。故本文应用MN-C和MN-P两种微晶纤维素膜基质考察了五种多环芳烃的RTP特征,并建立了它们的SS-RTP新方法。并与用滤纸作基质的实验结果进行了比较,表明两种新的固体基质的RTP性能优于滤纸基质。     

一锅合成异硫氰酸酯

以N,N-二乙基乙胺(Et₃N)为碱,甲苯为溶剂,伯胺和CS₂为原料,叔丁基碳酸二乙基磷酸酐(3)为脱硫试剂,在n(伯胺):n(CS₂):n(Et₃N):n(3)=1:1.1:3.3:1.1,二硫代甲酸盐合成段反应温度为室温,脱硫反应段为-5 ℃至室温的实验条件下,两步一锅合成了系列烷基、芳基和双功能基异硫氰酸酯化合物,收率77%96%。 本方法底物适用范围广,操作简单,对胺的各种保护基团耐受,不引起消旋化副反应。 脱硫剂3作为一种新的脱硫试剂,商业易得,安全有效。     

MgBr2·OEt2 mediated protection of alcohols with hexamethyldisilazane: An efficient catalytic route for the preparation of silyl ethers under solvent-free conditions

Various types of alcohols and phenols were rapidly protected by hexamethyldisilazane in good to excellent yields at room temperature in the presence of catalytic amount of magnesium bromide ethyl etherate under solvent-free conditions. Good to excellent chemoselectivity was demonstrated for competitive protection of primary hydroxyls in the presence of secondary and tertiary alcohols. Highly selective protection of phenols in the presence of aromatic amines was also demonstrated successfully.     

Iodination with Potassium Permanganate/Hydroiodic Acid/Acetonitrile Reagent

Iodination of various aromatic amines proceeds smoothly with a preformed homogeneous mixture of hydroiodic acid potassium permanganate in acetonitrile. para-Substituted products were obtained in high yields (71-78%) within twelve hours at room temperature. With a slight modification of the permanganate, hydroiodic acid and substrate ratio, iodination of alkynes to vic-diiodoalkenes can be carried out at 60 °C in 65-87% yield.     

The one-pot process for the preparation of <Emphasis Type="Italic">N</Emphasis>-monoalkyl aromatic amines from nitroarene derivatives

A series of N-monoalkyl aromatic amines are synthesized in high yields from corresponding nitroarene derivatives, aldehydes, and ammonium formate in the presence of Pd/C as a catalyst through one-pot operations at room temperature. Both the conversion and selectivity of the process are above 80%. Optimum reaction conditions are investigated, and it is found that the optimum molar ratio of nitroarene derivatives to ammonium formate and the optimum weight ratio of nitroarene derivatives to Pd/C are 1/4 and 1/0.10, respectively. These experiments provide a novel access for N-monoalkyl aromatic amines with advantages of simplicity, high selectivity, and environmental benignity.     

Kinetics and mechanism of the bromination of aromatic compounds by N-bromosuccinimide in solution

The kinetics of bromination of several aromatic compounds (anilides, anisoles, and phenols) was investigated in 80% aqueous acetic acid (v/v) in the temperature range 20–50°C using N-bromosuccinimide (NBS) as the reagent. The reaction was found to be first order in the aromatic substrate (ArH), and zero order in NBS, the overall order being 1. Stoichiometry of the reaction was 1:1. An increase in solvent polarity increased the reaction rate, and chloride ions were found to be specific catalysts for the reaction. Arrhenius activation energy remained almost constant for all the substrates. A probable mechanism explaining all these observed facts was proposed. The mechanism involved an attack by Br⁺ or more probably by a solvated Br⁺ ion on the aromatic substrate.     

Willgerodt-Kindler reaction at room temperature: Synthesis of thioamides from aromatic aldehydes and cyclic secondary amines

A simple method for the synthesis of thioamide derivatives in DMSO at room temperature and at 120 °C has been developed. Total 27 compounds were prepared under both conditions via a one-pot, three component reaction between substituted aromatic aldehydes, elemental sulfur powder, and cyclic secondary amines. By optimizing the mole ratio of sulfur powder and amines, we have successfully carried out Willgerodt-Kindler reaction of aromatic aldehydes at room temperature. At 120 °C, it is catalyst free reaction with lower reaction time whereas at room temperature, due to the additional amine molecule, Willgerodt-Kindler reaction of aromatic aldehydes is successfully carried out at room temperature. On gram-scale, the reaction is successfully attempted under both conditions with good yields.     

Regioselective Bromination of Aromatic Amines and Phenols Using N-Benzyl-DABCO Tribromide

N-Benzyl-DABCO tribromide, a stable, solid organic ammonium tribromide, has been used as a bromine source for the regioselective and high-yielding bromination of aromatic amines and phenols. Mono-bromination proceeds well in the presence of a stoichiometric amount of bromine source at room temperature.     

温和条件下对甲基苯磺酸铝高效催化一锅法合成β-氨基酮衍生物

室温条件下,对甲基苯磺酸铝可有效催化芳香酮、芳香醛和芳香胺的Mannich反应,三组分"一锅法"合成了一系列β-氨基酮衍生物.考察了溶剂及反应条件对产率的影响.反应结束后,催化剂经简单相分离可回收并多次重复使用,催化活性无明显下降.产物结构经IR,~1H NMR,元素分析进行表征.