三(对-甲苯磺酰氧甲基)硝基甲烷的还原和N-三(对-甲苯磺酰氧甲基)甲基羟氨的空气氧化

三(对-甲苯磺酰氧甲基)硝基甲烷(1)于苯中,以锌粉和醋酸在加或不加醋酸酐下可以被还原,并分別形成相应的羟氨(2)或其醋酸酯(3)。值得注意的是,当2和3以1M甲醇钠在氯仿中处理时,受空气氧化后又形成硝基化合物(1),但在排除空气时,不发生这一氧化反应。同样,三(苯甲酰氧甲基)硝基甲烷当用锌粉-醋酸还原时可生成相应的胺。     

水溶性葛根素衍生物的合成

以葛根素为起始原料,分别经亲核取代反应和羟甲基化反应得到水溶性4′-羟乙基葛根素和3′,5′-二羟甲基葛根素,对首次得到的3′,5′-二羟甲基葛根素,用正交实验对的合成条件进行了优化,当n(葛根素)∶n(甲醛)∶n(氢氧化钠)=1∶2∶4,反应温度为60℃,反应时间为4.0 h,产率为69.0%。目标化合物的结构经IR、~1H NMR、~(13)C NMR和元素分析方法进行表征。经测试4′-羟乙基葛根素和3′,5′-二羟甲基葛根素水溶性分别是葛根素的5倍和10倍。     

可回收铋配合物催化氮亲核试剂与对醌甲基化物1,6-加成:轻松获得N-杂环取代的不对称三芳基甲烷衍生物（英文）

开发了一种用对醌甲基化物(p-QMs)和各种芳香族N-杂环化合物1,6-氮杂-迈克尔加成合成含氮不对称三芳基甲烷衍生物的方法.这种合成方法具有反应条件温和、催化剂负载量可接受、原子经济性、易于放大的特点,并且能够以中等至优异的产率形成N-杂环取代的不对称三芳基甲烷衍生物.此外,铋催化剂可以重复使用多次而不会损失其活性.     

纳米晶碳化钨薄膜对硝基甲烷还原的电催化性能

采用磁控溅射物理气相沉积技术在金属镍基体上制备碳化钨纳米晶薄膜. 薄膜具有纳米晶结构, 由粒径为20~35 nm的晶粒构成, 晶粒分布均匀, 晶相结构为非化学计量比的碳化钨(WC1-x). 采用电化学方法研究硝基甲烷在纳米晶碳化钨薄膜电极上的电化学还原性能和反应机理. 实验结果表明, 碳化钨薄膜电极对硝基甲烷电化学还原反应具有较好的催化性能, 当电极电位为-0.89 V(vs.SCE)时, 硝基甲烷还原为甲基羟胺的电流达14.9 mA/cm2, 其反应表观活化能为12.3 kJ/mol. 硝基甲烷在碳化钨薄膜电极上经过一步不可逆的电化学反应还原成甲基羟胺, 其控制步骤是电极反应的电荷传递过程.      

5(6)-氨基-1-(4-氨基苯基)-1,3,3-三甲基茚满合成及工艺优化

以5(6)-硝基-1-(4-硝基苯基)-1,3,3-三甲基茚满为原料,Pd/C为催化剂,用氢气还原合成5(6)-氨基-1-(4-氨基苯基)-1,3,3-三甲基茚满。红外、核磁表征了产物结构;考察了反应温度、反应时间、充入氢气压力及催化剂用量四个因素,设计正交试验对还原工艺条件进行优化分析。结果表明,对粗产率的影响显著程度依次为充入H2压力、反应时间、反应温度和催化剂用量,获得了优化工艺条件,即反应温度70℃、反应时间为2 h、充入H2压力为1.5 MPa,催化剂用量为5(6)-硝基-1-(4-硝基苯基)-1,3,3-三甲基茚满的10%。     

基于Barton-Zard反应的2-乙氧羰基-3-三氟甲基-4-甲基吡咯及其卟啉衍生物的改进合成

由2-乙氧羰基-3-硝基-1,1,1-三氟丁烷(1b)与异氰基乙酸乙酯发生Barton-Zard反应制备2-乙氧羰基-3-三氟甲基-4-甲基吡咯(1)的过程中,分别用K2CO3和乙醇代替有机碱1,8-二氮杂二环[5.4.0]十一碳-7-烯(DBU)和四氢呋喃溶剂,这种改进的Barton-Zard方法具有操作简便、试剂价廉易得、溶剂毒性低和产率更高等优点。 另外,在3-硝基-1,1,1-三氟-2-丁醇(1a)通过乙酰化反应转变为中间体1b的过程中,用沸腾温度下的甲苯溶液与乙酰氯代替浓硫酸催化下的酸酐反应体系;合成化合物1b的最优化的反应条件被确定为：乙酰氯与反应物1a之间的摩尔比为1.2∶1,反应时间为3～3.5 h。 又根据改进的卟啉合成法,在低温下用过量氢化铝锂还原吡咯1,将还原所得的尚未干燥或储存的粗产物α-羟甲基-三氟甲基-4-甲基吡咯(1c),立即在未经处理的三氯甲烷溶剂中,以三氟化硼·乙醚(BF3·OEt2)为催化剂进行四聚化反应,然后用2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)氧化,合成出含三氟甲基取代的卟啉衍生物2。 研究发现,由化合物1c制备产物2时,用BF3·OEt2取代p-TsOH作为催化剂,在确定的反应条件下,能够将产物2的收率由14%提高至50%。     

功能化离子液体支载脯氨酸催化的不对称Henry缩合反应

以L-脯氨酸支载在功能化离子液体四氟硼酸1-(2-羟乙基)-3-甲基咪唑鎓盐上的离子液体([Promim]CF3CO2)为催化剂兼溶剂,可在温和条件下顺利地催化硝基乙烷、硝基甲烷和各种醛的Henry缩合反应,目标产物的产率达79％～95％,非对映选择性可达3∶1,对映选择性可达85%ee。 反应操作和后处理简单方便。 [Promim]CF3CO2离子液体通过简单的处理即可实现循环利用,以邻-硝基苯甲醛和硝基乙烷为反应底物的模板反应,这种离子液体可以较稳定地循环使用6次,催化活性不降。     

三羟甲基硝基甲烷电解还原机理的研究

本文报导利用线性扫描伏安法和控制电极电位电解研究三羟甲基硝甲烷电解还原的机理,从而选取适宜的电解条件获得了高产率的三羟甲基氨基甲烷。     

Eu(NTf2)3催化吲哚与醛(酮)反应合成二吲哚基甲烷

二(三氟甲基磺酰)亚胺铕(Ⅲ)[Eu(NTf2)3,Tf=SO2CF3]作催化剂,吲哚与醛(酮)在室温下发生亲电取代反应合成了一系列二吲哚基甲烷,产率85%～98%.该法反应条件温和、时间短、催化剂用量少且可以回收重复使用.     

Na2CO3催化的叠氮三甲基硅烷对δ-三氟甲基-δ-芳基取代对亚甲基苯醌的1,6-共轭加成: 高效构建含三氟甲基和叠氮取代的二芳基甲烷化合物

报道了一种高效的δ-三氟甲基-δ-芳基-取代对亚甲基苯醌的叠氮化芳基化反应. 以Na₂CO₃为催化剂, 叠氮三甲基硅烷与δ-三氟甲基-δ-芳基取代对亚甲基苯醌发生1,6-共轭加成反应, 以优异的分离产率(90%~96%)获得了结构多样的含有三氟甲基和叠氮取代的二芳基甲烷化合物.该反应具有良好的底物适用范围和官能团兼容性.     

Complexing properties of N-[1,1-bis(hydroxymethyl)ethyl]-and N-[tris(hydroxymethyl)methyl]-β-alanine

Russian Chemical Bulletin - Protolytic and complexing properties of N-[1,1-bis(hydroxymethyl)ethyl]- and N-[tris-(hydroxymethyl)methyl]-β-alanine were estimated using the potentiometry. Values...     

Palladium nanoclusters entrapped in polyurea: A recyclable and efficient catalyst for reduction of nitro-benzenes and hydrodechlorination of halogeno-benzenes

Polyurea-entrapped palladium nanoclusters have been prepared by interfacial polymerization in W/O emulsion and showed high thermal stability and chemical stability with the content of 0.12 mmol g^?1 Pd. This catalyst exhibited dual catalytic activity for reduction of nitro compounds and hydrodehalogenation of aromatic chlorides in atmospheric hydrogen with 100% yield for reduction of nitro compounds and >99% yield for hydrodehalogenation of aromatic chlorides. This immobilizing method was particularly effective and eliminated the need of special chelating groups.     

Determination of the Major Factors of Fermentation of the Nebramycin Complex by High Performance Liquid Chromatography

Abstract

For the determination of the major factors (tobramycin, kanamycin B, apramycin) from the fermentation broth a new method has been developed with combination of some earlier published method. In this method the protein content of the mixture was removed by treatment with tris-(hydroxymethyl)-aminomethane followed by centrifuging then the antibiotic content was derivatized by 1-fluoro-2,4-dinitro-benzene, The mixture was analysed on a reversed phase column.     

Temperature-Dependent Structure-Energy Changes in Crystals of Compounds with Poly(hydroxymethyl) Grouping

Crystals of tris(hydroxymethyl)nitromethane (1) and tris(hydroxymethyl)aminomethane (2) were prepared and grown at room temperature. X-ray analysis was used to study the structure of crystals 1 and 2 at room temperature; the X-ray diffraction method was applied to investigate polycrystalline samples during a temperature rise up to the phase transition into the plastic phase. Phase transitions in separate crystals 1 and 2 were observed in a hot stage under an optical microscope. Calorimetric study of the crystal temperature behavior and the phase transition features including melting were carried out. By IR spectroscopy the temperature relations of the bonds of symmetric N-O stretching vibrations of nitro groups and stretching vibrations of OH groups redistribution in crystals of 1 were investigated. In crystals of 2 the behavior of stretching vibration bands of O-H groups was studied at room temperature. In the temperature interval including phase transition, data on structure-dynamic rearrangements in the crystal lattice of compounds 1 and 2 were obtained by the NMR pulse method in the solid phase using relaxational free induction decay of protons. The proton conductivity was found and its temperature parameters were determined for both compounds in the plastic state.     

芳香硝基化合物原位液相加氢一锅法合成喹啉类化合物

以芳香硝基化合物为起始原料,以2%Pt-Sn/γ-Al2O3为催化剂,采用原位液相加氢法可以一锅法合成喹啉类化合物,考察了Pt/Sn摩尔比、反应温度、原料浓度和水含量等对反应性能的影响.结果表明,在Pt/Sn摩尔比0.5,220oC,5.0MPa,原料浓度6%,水含量30%及反应物停留时间为72s的条件下,生成产物6-甲氧基-2-甲基喹啉的收率可达72%.     

peri-Naphthalenediamines: XXXIV. 1,4,5,8-Tetrakis(dimethylamino)naphthalene: Alternative Approaches to Synthesis

New methods were proposed for synthesizing 1,4,5,8-tetrakis(dimethylamino)naphthalene with an overall yield of 4 to 12% to replace the known procedure ensuring an overall yield of 2%. Catalytic hydrogenation was shown to be inapplicable for preparation of polyaminonaphthalenes from nitro compounds having 3 or 4 nitro gruops in the -positions. Nucleophilic amination of 1,5-dinitronaphthalene in the system NH₂OH/NaOH/MeOH yields 1-amino-4-nitronaphthalene. The nitration of 1,5-bis(p-tolylsulfonylamino)naphthalene leads to formation of 2,6-dinitro rather than 4,8-dinitro derivative, as it was believed formerly. This was confirmed by transformation of the latter into 1,2,5,6-tetrakis(dimethylamino)naphthalene. 3-Nitro, 2,6-dinitro, 2,6-diamino, and 2,4,6,8-tetranitro derivatives of 1,5-bis(dimethylamino)naphthalene, nitro and amino derivatives of 1,4,5-tris(dimethylamino)naphthalene, and 4,5-diamino-1,8-bis(methylamino)naphthalene were synthesized. By treatment with perchloric acid 1,4,5,8-tetrakis(dimethylamino)naphthalene was oxidized to 2,3-dihydroperimidinium salt.     

Electrosynthesis of 5-amino-4-oxopentanoic acid hydrochloride

The electroreduction of methyl 5-nitro-4-oxopentanate was studied by means of a polarographic method and preparative electrolysis in acidic-alcoholic solutions. The effects of the following factors on the yield and quality of 5-amino-4-oxopentanoic acid hydrochloride were studied: the cathode material, amount of electricity, temperature, nature of the solvent, concentrations of the initial nitro compound and hydrochloric acid, and the cell design. It was shown by electrolysis at a controlled potential and in a galvanostatic mode that the products of methyl 5-nitro-4-oxopentanate electroreduction are hydroxyamino and amino compounds, and also ammonium chloride, nitromethane, methylhydroxylamine hydrochloride, and monomethylamine hydrochloride. Their ratio depends on the electrolysis conditions. The highest overall substance yield (61.1–66.0%) and current yield (68.1–68.6%) of 5-amino-4-oxopentanoic acid hydrochloride was achieved at a copper cathode in a filter-press cell. The content of the main substance in the electrochemically obtained samples of 5-amino-4-oxopentanoic acid was 89.5–91.0%.     

用NMR方法测定三羟甲基胺基甲烷的质子解离常数

文献[1]中已报导了三羟甲基胺基甲烷(缓血酸胺,THAM)的质子解离常数。我们用¹H和¹³C NMR方法研究了这一试剂的质子解离过程。     

用分子子图法计算硝基呋咱化合物的生成热

用新的分子子图法计算硝基呋咱类化合物的生成热,将呋咱基团视为母体,即基子图项;硝基、叠氮基、甲基、氰基拆分为一个个原子,从原子的角度来分分子子图,将碳、氢、氧、氮原子视为取代基,即亚子图项.同时考虑呋咱基团的个数,考虑1位、 2位、 3位、 4位上碳、氢、氧、氮原子及双键、叁键对生成热的影响,还考虑不饱和度、总硝基个数、环的个数(除呋咱环)、氮氮及氮氧双键的个数对生成热的影响.用这种新的分子子图编码方法,对硝基呋咱化合物的生成热进行了拟合和预估,取得了满意的结果,其回归方程的相关系数达到了0.9954.     

Photoreduction of nitro arenes by formic acid in acetonitrile at room temperature

The formic acid-mediated photoreduction of aromatic nitro compounds in room temperature acetonitrile solutions was investigated. This mild photoreduction can be accomplished in high yield, with wide functional group tolerance and short reaction times (30 min to 1 h), and allows a very clean method for the conversion of nitro arenes to amines. Also, the photoreduction, as a convenient, versatile and general method, applies efficiently to polycyclic and heterocyclic nitro arenes.