α-溴代羰基化合物脱溴的一种简便方法

卤代物的脱卤反应是有机合成中重要反应之一,应用有机碲试剂使某些邻二溴代物脱溴反应及α-卤代羰基化合物的脱卤反应已有文献报道。我们在研究碲 Ylide 反应过程中发现二丁基碲能使某些单取代的α-溴代酮发生脱溴反应,这是一种未见文献报道的新的脱溴反应。为了考察二丁基碲作为一种新的脱溴试剂应用的可能性,我们对二丁基碲的脱     

新型葡萄糖氮苷化合物的合成与表征

通过自由基溴代反应得到活性中间体溴代二甲戊乐灵, 再以2,3,4,6-四-O-乙酰化-β-葡萄糖胺亲核取代得到一种新型糖苷化合物, 产物经MS和NMR进行表征.     

N-(溴代-2-吡咯甲酰基)氨基酸甲酯的合成

在室温条件下, 2-三氯乙酰基吡咯经溴代反应, 再与氨基酸甲酯反应得到一系列N-(溴代-2-吡咯甲酰基)氨基酸甲酯, 收率为64.8%～92.2%. 通过元素分析, ¹H NMR, IR和MS对产物结构进行了表征, 培养了N-(1-甲基-4,5-二溴-2-吡咯甲酰基)甘氨酸甲酯的单晶并进行单晶X射线衍射分析. 初步活性试验表明, 目标产物对金黄色葡萄球菌、粪链球菌等五种细菌有一定的抑制作用.     

2-氯甲基呋喃与三烷基炔基硼酸盐的反应研究

近几年来,有机硼酸盐的化学是一个非常活跃的研究领域,三烷基炔基硼酸盐能与许多亲电试剂进行立体选择性的反应,经质子解,得到各种各样的三取代烯烃,其一般反应式如方程式(1)。在这些亲电试剂中,有的亲电试剂如:溴丙烯、溴苄、溴代丙酮、溴代     

5-甲基-[(2E,6E)-3,7,11-三甲基-9-氧代十二碳二烯]苯醌和氢醌的首次全合成

以2-甲基对苯二酚和香叶基溴为起始原料, 经过酚羟基保护, 溴代, Li₂CuCl₄催化的芳基溴与Grignard试剂的偶联以及Julia偶联等一系列反应, 完成了裸鳃亚动物的代谢产物, 5-甲基-[(2E,6E)-3,7,11-三甲基-9-氧代十二碳二烯]苯醌(1)和氢醌(2)的首次全合成, 将1用NaBH₄还原, 得到(±)-3, (±)-3也是此类天然产物之一.     

吉咪替康的合成新方法

10-羟基喜树碱首先在N,N-二甲基甲酰胺(DMF)中经N-溴代丁二酰亚胺(NBS)溴代得到9-溴-10-羟基喜树碱, 9-溴-10-羟基喜树碱和氯甲酸乙酯反应得到9-溴-10-羟基喜树碱-10,20-双乙氧基碳酸酯(6). 化合物6和烯丙基三正丁基锡通过Stille偶联反应^[9]得到关键中间体7, 最后水解化合物7得到目标化合物. 通过柱层析纯化得到纯度大于99.8%, 单杂小于0.1%的吉咪替康(HPLC). 所有中间体及目标产物经¹H NMR, ¹³C NMR, LRMS, HRMS表征确证.     

官能化二硫缩烯酮的选择性α-溴代反应

发展了一种适用范围广、高效且高选择性的官能化二硫缩烯酮的α-溴代反应.在少量水存在下,在四氢呋喃溶液中,以溴化铜为溴代试剂,经由官能化二硫缩烯酮(1)的α-溴代反应制备了结构多样的α-溴代二硫缩烯酮(2).     

溴水与苯酚反应产物的探讨

通过查阅文献和实验探究了苯酚的几种溴代产物在水、苯酚熔液和苯酚水溶液中的溶解性;从有机反应的理论角度探讨了苯酚溴代反应机理及产物的确证,指出苯酚与溴水反应的产物是2,4,6-三溴苯酚。     

光照条件下碳-硅键断裂及其溴代反应研究

研究了在高能量紫外光照条件下,苄基硅试剂的碳-硅键断裂过程及随后的高效溴代反应.该反应在紫外光照条件下,室温下即可温和且高效地进行,从而发展了一套新型的由苄基硅试剂合成苄基溴代物的方法.同时提出了该反应的可能机理.     

ZnAl-BrO_3~--LDHs/KBr溴源在苯胺类化合物选择性氧化溴代的应用（英文）

以醋酸/水为溶剂,用溴酸根插层的水滑石和溴化钾为溴源,室温下完成对苯胺类化合物的选择性氧化溴代反应.成功合成苯胺类化合物的单溴代和多溴代的目标产物,并获得较高产率.考察了底物结构及反应条件对反应选择性的影响.应用该溴源试剂,环境友好,操作简单,产率高,是一种合成溴代苯胺类化合物的新途径.     

Allyl tetrahydropyranyl ether: a versatile alcohol/thiol protecting reagent

Allyl tetrahydropyranyl ether (ATHPE) can be used as a versatile protecting reagent. In combination with NBS/I₂, O-allyl group can easily be replaced by hydroxyls (including tertiary-OH) or thiols, in the molecules comprising other reactive functional groups such as halogen, nitro, acetonide and alkene under mild reaction conditions (near neutral pH and ambient temperature).     

A facile and rapid one-step synthesis of 8-substituted xanthine derivatives via tandem ring closure at room temperature

N-Bromo succinimide (NBS) was found to be an efficient and regioselective reagent in combination with AIBN for an unprecedented, facile and rapid one-step synthesis of 8-substituted xanthine derivatives at room temperature. The inexpensive, nontoxic and readily available NBS efficiently promoted the condensation of several aryl/cycloaryl/heteroaryl aldehydes with 5,6-diamino-1,3-dimethyluracils in presence of catalytic amount of AIBN in a single step via radical chain reaction. The notable advantages of this protocol were short reaction time, milder reaction conditions, simple work-up procedure, no requirement for chromatographic separation, use of non-hazardous reagent/solvent and applicable to a variety of substrates.     

2-异丙基-1,3-二氢-4(1H)异喹啉酮及其衍生物的合成

报道了异喹啉酮与格氏试剂反应合成四氢-4-羟基异喹啉酮化合物,NBS和混酸(HNO~3/HAc)与异喹啉酮反应合成异喹啉酮衍生物。6个新化合物的结构,通过元素分析,红外光谱和核磁共振氢谱,质谱给予证实。     

Trace determination of iron,cobalt, nickel and copper in zirconium fluoride by substoichiometric radioactivation analysis

Trace amounts of transition elements (Fe, Co, Ni and Cu) in zirconium fluoride and NBS SRM's were determined by substoichiometric radioactivation analysis. The contents of impurities in sublimed sample were less than those of high-purity material and of reagent grade. The detection limits of these elements in zirconium fluoride were 10 ng/g for iron, 0.01 ng/g for cobalt, 1 ng/g for nickel and 0.1 ng/g for copper. The analytical results for iron, cobalt, nickel and copper in NBS SRM's were in good agreement with certified values.     

The polarographic behaviour of ketoprofen and assay of its capsules using spectrophotometric and voltammetric methods

The quantitative determination of ketoprofen using spectrophotometric and voltammetric methods are described. The spectrophotometric procedure depends upon the reaction of ketoprofen with N-bromosuccinimide (NBS). The residual reagent is then determined by formation of violet colour with 2,2-diphenyl-l-picryl hydrazine (DPPH(2)). The consumed NBS would correspond to ketoprofen. Beer's law is valid over the concentration range 5-80 mug/ml of the drug. Direct current (DC) polarography allows to study the reduction behaviour of ketoprofen at the dropping mercury electrode (DME) using different supporting electrolytes at different pH values. Direct current stripping voltammetry (DCSV) was used for the quantitative measurements of the drug. The calibration graph of peak current vs concentration was linear from 0.254 x 10(-2) to 0.254 mug/ml. In model solutions as little as 5.08 x 10(-4) ng/ml ketoprofen can be detected by DCSV. Both methods were applied successfully for the determination of ketoprofen either in pure or dosage forms.     

Three simple spectrophotometric methods for the determination of sulphinpyrazone

Three simple and sensitive spectrophotometric methods for the determination of sulphinpyrazone (SP) in bulk samples and pharmaceutical formulations are described. They are based on the oxidation of sulphinpyrazone with excess N-bromosuccinimide (NBS) and determination of the unconsumed NBS with metol-isonicotinic acid hydrazide (method A, lambda(max): 620 nm); by the reduction of Folin-Ciocalteu reagent (method B, lambda(max) 770 nm); or by the formation of a chloroform-soluble, coloured ion-association complex between the drug and Methylene Violet (MV) at pH 7.0 (method C, lambda(max) 545 nm).     

Determination of traces of mercury using radioactive zinc dithizonate as a reagent

A radioreagent method for the analysis of traces of mercury using radioactive zinc dithizonate as the reagent has been developed. As small as 0,2 μg of mercury can be determined using this technique. Possible interferences from most of the metals which displace zinc from zinc dithizonate can be removed by a simple separation procedure. The method was tested by analyzing the NBS reference standard SRM 1064 and our value was found to be in agreement with the value certified by NBS. This paper was presented at the South-East and South-West ACS Regional Meeting, Memphis, Tenn., October 29–31, 1975.     

Bromination by means of sodium monobromoisocyanurate (SMBI)

A variety of aromatic compounds with both activating and deactivating substituents were brominated with sodium monobromoisocyanurate (SMBI) 1, diethyl ether, diethyl ether-methanesulfonic acid, trifluoroacetic acid, or sulfuric acid were employed as solvents. Thus nitrobenzene was conveniently brominated in sulfuric acid, benzene was readily monobrominated in diethyl ether-methanesulfonic acid, and phenol was selectively brominated at the ortho position under mild conditions in refluxing diethyl ether. With substituents that are easily protonated, trifluoroacetic acid may be employed as solvent in the reaction with 1, in contrast NBS was ineffective in trifluoroacetic acid. This renders 1 a superior reagent relative to NBS. In addition to aromatics, alkenes, ketones and esters were also brominated with 1. Diethyl malonate was brominated with 1 and then subjected to a Bingel reaction with NaH to afford the desired methanofullerene in reasonable yield.     

NBS-mediated synthesis of β-keto sulfones from benzyl alcohols and sodium arenesulfinates

An efficient synthetic route towards the synthesis of β-keto sulfones has been developed from secondary benzyl alcohols using N-bromosuccinimide (NBS). The present protocol utilizes NBS as oxidant as well as brominating agent, readily accessible benzyl alcohols and sodium arenesulfinates as the sulfonylating reagent under mild conditions. The control experiments revealed that the reaction proceeds via oxidation of alcohol to ketone, α-bromination of ketone and nucleophilic substitution by sodium arenesulfinate. Furthermore, the efficiency of the methodology was tested with a gram scale reaction and also shown the synthetic utility.     

Spectrophotometric determination of astemizole

Four simple and sensitive spectrophotometric methods for the determination of astemizole (AZ) in pure samples and pharmaceutical formulations are described. They are based on the oxidation of astemizole with excess N-bormosuccinimide (NBS) and determination of the unconsumed NBS with, metol-sulphanilamide (method A, lambda(max): 520 nm) or celestine blue (method B, lambda(max): 540 nm); or by the reduction of Folin-ciocalteu reagent (method C, lambda(max): 720 nm); or by the formation of a chloroform-soluble, coloured ion-association complex between the drug and azocarmine G (AG) at pH 1.5 (method D, lambda(max); 540 nm). The results obtained are reproducible with a coefficient of variation of less than 1.0%.