硼氢阴离子交换树脂的制备及其对羰基、酰氯化合物的还原

Gibson和Bailey首次应用Cl型季铵型强碱性阴离子交换树脂与NaBH_4交换,制备了硼氢阴离子交换树脂还原剂(简称BER)。     

离子交换树脂用作聚合物试剂方面的新进展

本文综述由离子交换树脂为原料制备的聚合物离子型试剂.绝大多数的聚合物离子型试剂是用强碱性阴离子交换树脂制备的,它包括氧化剂、还原剂、20余种亲核试剂以及卤化剂等.约有40多种聚合物试剂可全由强碱性阴离子交换树脂制备.由强酸性阳离子交换树脂所制成的试剂只有数种.弱酸性阳离子交换树脂所制成的试剂,只是刚刚开始.弱碱性阴离子交换树脂可制成的试剂几乎没有.     

聚合物硼氢阴离子还原剂的制备及其对酯的还原研究

氯型季我安盐型强碱性阴离子交换树脂７１１＾＃与硼氢化钾反应制得聚合物硼氢阴离子还原剂，树脂容量３．２ｍｍｏｌ ＢＨ４／ｇ。用于不同酯化合物的还原，操作简便，树脂可再生重复使用。     

取代邻硝基苯酚的聚合物负载催化剂还原反应

制备了聚合物硼氢阴离子交换树脂（BER）、活性碳钯（Pd／C）和聚合物负载金属钯（Pd／D411）等催化剂，对各种取代的邻硝基苯酚进行了催化氢化还原反应。比较了上述三种催化剂对各种底物的催化活性的影响。研究结果表明：当邻硝基苯酚的苯环上取代基不同或取代基的位置不同时，它们被还原的难易程度不同。另外，催化剂载体对催化剂的性能也有很大影响。     

聚合物支载硼氢根阴离子交换树脂I_2系统还原羧酸的研究

本文采用聚合物支载硼氢根阴离子交换树脂／I2系统还原羧酸类化合物，发现它具有很好的还原选择性和还原效果，并对影响该反应的条件如温度、溶剂进行了讨论。     

新的聚合物支载硼氢负离子还原剂系统研究 3: 聚合物支载还原剂III

硼氢化钠的低分子还原系统研究很多,但其聚合物支载还原剂相对来说就很少,而且仅以强碱型阴离子交换树脂来制备的聚合物试剂。为了寻找用途更广泛的、新的聚合物支载还原剂,我们进行了硼氢负离子的聚合物还原系统的研究;发现能用弱酸型阳离子交换树脂制备出新的聚合物支载还原剂。前文报道了用NaBH_4的水溶液和阴离子交换树脂     

离子交换树脂负载Pd-Cu双金属催化剂的制备及其对硝酸盐的催化脱除作用

采用阴离子交换树脂(AIER)为载体.以络合剂EDTA为媒介物,制备了Pd-Cu双金属负载性型催化剂;以H2为还原剂,将催化剂应用于水介质中NO3-还原为N2的脱除反应;考察了双金属催化剂组成、载体阴离子交换树脂的性质及水介质中NaCl存在对还原脱除反应的影响规律.研究结果表明,凭借阴离子交换树脂对EDTA强烈的吸附作用及EDTA对金属离子的强螯合作用,可将大量的金属离子(Cu2 与Pd2 )结合到树脂表面,再通过水合肼的还原作用,可制得金属负载量高且结合程度牢的双金属负载性型催化剂Pd-Cu/AIER.在单纯含有硝酸盐的水溶液中,在催化剂Pd-Cu/AIER的作用下,NO3-只能被还原为NH4 ,不能还原为N2;水介质中大量氯离子的存在,能大大促进NO3-转变为N2的还原反应;载体阴离子交换树脂的碱性越弱,最终制得的催化剂活性与选择性越差.     

耐高温强碱阴离子交换树脂研究进展

羟型强碱阴离子交换树脂的最高使用温度一般为60□,三菱化学公司研究制备了能耐受100□高温的强碱阴离子交换树脂.本文对近年来强碱阴离子交换树脂在热稳定性方面的改进及提高做简要概述.     

聚合物支载硼氢根阴离子交换树脂：Ⅰ2系统还原羟酸的研究

本文采用聚合物支载硼氢根阴离子交换树脂／Ｉ２系统还原羟酸类化合物，发现它具有很好的还原选择性和还原效果，并对影响该反应的条件如温度、溶剂进行了讨论。     

pH和盐对树脂吸附芳香酸的影响研究

通过三甲胺修饰超高交联聚苯乙烯树脂NJ-00制备了一种新型树脂(NJ-03),树脂性质表征说明,通过改性季胺基被成功引入,树脂骨架上增加了一定数量的碱性基团。研究了pH、盐浓度对芳香酸类化合物在NJ-03树脂上吸附的影响,并与商品大孔强碱阴离子交换树脂D-201以及大孔弱碱阴离子交换树脂D-301进行对比,探讨了pH和盐浓度影响吸附的机理。     

含不同基团偶氮苯化合物的合成及其光致异构化性质

以苯胺或对硝基苯胺为起始原料,通过重氮偶合法合成了4种分别含有硝基、氨基和不同数目偶氮基的偶氮苯化合物(1~4),其结构经¹H NMR和FT-IR确证。研究了1~4在紫外灯(12 W)照射下随时间变化的UV-Vis谱图。结果表明：含有给电子基团(NH₂)偶氮苯的光致异构化速率较含有吸电子基团（NO₂）时更快,NO₂对分子的异构化有一定抑制作用;分子中偶氮基的数目增加时,顺反异构化过程也受到影响。     

新试剂2-(2-氰基-4-硝基-6-溴苯偶氮)-6-异丙基苯酚的合成及金属离子显色反应

本文以２－氰基－４－硝基－６－溴苯胺为原料，经重氮化后与邻异丙基苯酚偶联，合成２－（２－氰基－４－硝基－６－溴苯偶氮）－６－异丙基苯酚，用乙醇重结晶精制。用元素分析，波谱等鉴定其结构，并测定其离解常数，研究该试剂的一般性质。发现其与Ｃｕ２＋、Ｎｉ２＋、Ｃｏ２＋等的显色反应在吐温８０表面活性剂存在下有较高的灵敏度。     

Selective reduction of aromatic nitro compounds with stannous chloride in non acidic and non aqueous medium

Aromatic nitro compounds are readily reduced by SnCl₂, 2 H₂O in alcohol or ethyl acetate or by anhydrous SnCl₂ in alcohol where other reducible or acid sensitive groups such as aldehyde, ketone, ester, cyano, halogen and O-benzyl remain unaffected.     

Direct conversion of carbonyl compounds into organic halides: indium(III) hydroxide-catalyzed deoxygenative halogenation using chlorodimethylsilane

The reaction of carbonyls and chlorodimethylsilane was effectively catalyzed by indium(III) hydroxide and afforded the corresponding deoxygenative chlorination products, in which the carbonyl carbon accepted two nucleophiles (H and Cl) with releasing oxygen. Only In(OH)3 catalyzed the reaction, and typical Lewis acids such as TiCl4, AlCl3, and BF3.OEt2 showed no catalytic activity. The reaction mechanism of this deoxygenative chlorination includes initial hydrosilylation followed by chlorination. Other nucleophiles such as allyl or iodine were available for this methodology. The moderate Lewis acidity of indium catalyst enabled chemoselective reaction, and therefore ester, nitro, cyano, or halogen groups were not affected during the reaction course.     

A facile and convenient synthesis of functionalized ortho-nitrophenylboronic acids

A variety of ortho-nitrophenylboronic acids bearing functional groups such as cyano, nitro, halo, α-bromomethyl, and ester were prepared in good yields via I-Mg exchange followed by quenching with trimethyl borate. All reagents employed in this procedure are commercially available and were used without further purification, and the procedure can be executed in about an hour.     

Application of DMF-methyl sulfate adduct in the regioselective synthesis of 3-acylated indolizines

A number of 3-acylated indolizines were synthesized in good to excellent yields by a newly established reaction between picolinium salts and the methylsulfate salt of A (R = Me), the adduct formed from DMF-Me₂SO₄ as the key reagent. The low cost, short reaction time, mild reaction condition, and easy purification of the products make this an attractive new method for the synthesis of indolizine compounds. A variety of functional groups (nitro, cyano, ester, methoxy, and halogens) were well tolerated under the reaction conditions.     

Cobalt-catalyzed hydro-difluoromethylthiolation/hydro-trifluoromethylthiolation of unactivated alkenes

An efficient Co-catalyzed hydro-difluoromethylthiolation/hydro-trifluoromethylthiolation reaction of unactivated alkenes was described. Both reactions were conducted at room temperature and a variety of common functional groups such as halogen, ester, aldehyde, enolizable ketone or ester, nitro or cyano group, sulfonate and carbamate were compatible with the reaction conditions. Radical cyclization and radical inhibitor experiments suggested that the reaction proceeds through a free radical process.     

Extremely Fast Gas/Liquid Reactions in Flow Microreactors: Carboxylation of Short‐Lived Organolithiums

Carboxylation of short‐lived organolithiums bearing electrophilic functional groups such as nitro, cyano, and alkoxycarbonyl groups with CO₂ to give carboxylic acids and active esters was accomplished in a flow microreactor system. The successful reactions indicate that gas/liquid mass transfer and the subsequent chemical reaction with CO₂ are extremely fast.     

Disulfonyl carbon acids – synthesis,spectroscopic and structural studies – a review

The subject of carbon acids activated by two sulfonyl groups is reviewed. It will be shown that the studied compounds are relatively strong acids that have their importance in organic chemistry. The structure and reactivity of the products of the deprotonation reaction are also described. Structural studies using X-ray and spectroscopic methods such as IR, NMR or MS give more information about their proton donor properties. They are supplemented by charge distribution research in these carbanions using empirical evaluation and electron density ab initio calculation. A comparison of the results obtained for the title compounds with data obtained for other carbon acids activated by nitro or cyano groups is presented.     

Palladium-catalyzed borylation of aryl halides or triflates with dialkoxyborane: A novel and facile synthetic route to arylboronates

A direct borylation of aryl halides or triflates with dialkoxyborane was investigated. The coupling reaction of pinacolborane with aryl halides or triflates in the presence of a catalytic amount of PdCl(2)(dppf) together with a base provided arylboronates in high yields. The product distributions were strongly dependent on the base employed, and the tertiary amine, especially Et(3)N, was effective for the selective formation of the boron-carbon bond. The reaction conditions were so mild that arylboronates having a variety of functional groups such as carbonyl, cyano, and nitro groups were readily prepared.