毛细管气相色谱法测定果蔬中20种有机磷农药残留量

毛细管气相色谱法测定果蔬中２０种有机磷农药残留量庄无忌周昱（中国商检技术研究所北京１０００２５）（厦门商检局厦门３６１０１２）１前言食品中多种有机磷农药残留量的测定国外已有报道￣［１～４］,国内也正在开展此项工作。李聪等￣［５］曾报道了低脂肪样品中１...     

止痛胶囊中甘草酸含量测定方法

止痛胶囊中甘草酸含量测定方法杨吉田，邵长凤（天津市计划生育研究所，３００１９１）孙家莉，王文彤，刘继云（天津市药物合成研究所）甘草中甘草酸的分析方法，文献有些报导如：薄层紫外分光光度法￣［１］，高效液相色谱法￣［２，３］。但对止痛胶囊中甘草酸的含量测...     

手性柱前衍生高效液相色谱法拆分牙本质中天冬氨酸对映体

手性柱前衍生高效液相色谱法拆分牙本质中天冬氨酸对映体傅世江,范垂昌,张世鑫魏奉群赵婷（中国医科大学法医化学教研室沈阳１１０００１）（辽宁基础医学研究所沈阳ｌ１０００３）（辽宁省分析测试研究中心沈阳１１００１５ｊ１前言由于氨基酸消旋化理论￣［１］在考古...     

高效液相色谱法分离纯化人胎盘泌乳素酶切片段

高效液相色谱法分离纯化人胎盘泌乳素酶切片段杨煜,杨波,麦荫乔（白求恩医科大学长春１３００２１）１前言人胎盘泌乳素（Ｈｕｍａｎｐｌａｃｅｎｔａｌｌａｃｔｏｇｅｎ,ＨＰＬ）是由胎盘绒毛滋养层的合体细胞分泌的一种单链多肽类激素。它主要有催乳作用￣［１］及促...     

白酒中C_9－C_（18）脂肪酸的气相色谱分析

白酒中Ｃ＿９－Ｃ＿（１８）脂肪酸的气相色谱分析周在德，曾永昌（四川大学化学系成都６１００６４）关键词气相色谱法，白酒，Ｃ＿９－Ｃ＿（１８）脂肪酸。白酒中脂肪酸的含量及相互比例关系，极大地影响着白酒的色，香，味，风格￣（［１］［２］）。一般采用的化学分...     

柱色谱法分离地榆中的鞣质和皂甙

柱色谱法分离地榆中的鞣质和皂甙王满力，陈桐（贵州工学院化工系贵阳５５０００３）ｌ前言从中草药植物中革取的鞣质和皂甙极不易分离，严重地制约了它们的开发利用￣［１，２］。本文采用色谱半干柱酸度梯度淋洗法￣［２，３］，可将地榆中鞣质和皂甙完全分离，并观察到...     

催化动力学光度法测定痕量锰的研究

催化动力学光度法测定痕量锰的研究周华方，张明珠（徐州师范学院化学系，２２１００９）王镇浦（南京化工学院应化系，２１０００９）近年来，光度法测定锰已有一些报道，目前主要报道直接显色法￣［１１］、间接法￣［２］和催化动力学法￣［２－４］，比较这几种方法。...     

人工神经网络法预测有机物临界体积研究

人工神经网络法预测有机物临界体积研究张向东（辽宁大学化学系沈阳１１００３６）赵立群，张国义（沈阳化工学院高分子化工系１１００２１）１基本原理￣［１］最近几年国内外学者将人工神经网络方法应用于解决化学问题收到较好效果￣［２］。误差反向传播（ＢＰ）模型是...     

反相高效液相色谱法测定3，5－二硝基邻甲苯酰胺含量

反相高效液相色谱法测定３，５－二硝基邻甲苯酰胺含量翟素琴，吕青涛（山东建筑工程学院，济南２５００１０）（山东中医学院，济南２５００１４）３，５－二硝基邻甲苯酰胺（Ｚｏａｌｅｎｅ）是一种饲料添加剂，可有效地预防和治疗鸡球虫病￣［１］，是抗家畜球虫病的重...     

DNA双螺旋结构发现的背景

ＤＮＡ双螺旋结构发现的背景张金菊（南京师范大学化学系，南京２１００２４）１９５３年春，英国剑桥卡文笛什实验室的两位科学家沃森（Ｗａｔｓｏｎ）和克里克（Ｃｒｉｃｋ），在英国《自然》杂志上发表了一篇题为“核酸的分子结构”的通讯￣［１］，阐明了核酸是由两条...     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.