对硝基邻苯二乙醚合成技术研究

以邻苯二酚与溴乙烷为原料、聚乙二醇为相转移催化剂合成邻苯二乙醚,再经过冰醋酸和硝酸硝化得到对硝基邻苯二乙醚。研究了反应温度、反应时间、原料摩尔比和催化剂用量等对反应收率的影响,获得了合成邻苯二乙醚的优化工艺条件:n(C6H4(OH)2)∶n(NaO H)∶n(C2H5Br)=1∶2.6∶2.4,反应温度80℃,反应时间4h,催化剂用量2g,该反应条件下邻苯二乙醚平均收率88%。混酸硝化条件下合成对硝基邻苯二乙醚的较佳工艺条件为n(C10H14O2)∶n(HNO3)=1∶1.2,乙酸25mL,反应时间30min,反应温度20℃,该反应条件下对硝基邻苯二乙醚平均收率为99%。     

氯化磷酸二苯酯的合成和结构表征

以苯酚、三氯氧磷为原料,以无水三氯化铝为催化剂合成了氯化磷酸二苯酯;采用正交试验研究了反应温度、反应时间、催化剂用量和原料配比对反应收率的影响,确定了最佳工艺条件;并利用红外光谱和核磁共振谱表征了产物的结构.结果表明,影响反应收率的几种因素的排序为:反应温度>原料配比>催化剂用量>反应时间;最佳反应条件为:温度70℃、反应时间15h、原料配比(n苯酚∶n三氯氧磷)2∶1、催化剂用量0.8g(相对于苯酚的质量分数为4.25%).与此同时,采用加水后处理方法可以提高产品收率和可操作性.     

β-二酮钴配合物催化空气氧化二苯甲醇反应的研究

研究了β-二酮钴催化空气氧化二苯甲醇生成二苯甲酮的反应．利用正交实验方法考察了反应温度、时间、N-羟基邻苯二甲酰亚胺(NHPI)用量、催化剂种类及用量对反应的影响．发现同一金属中低价态β-二酮金属配合物的活性较高，配体给电子能力强，催化活性就越高．当反应温度80℃、反应时间12h、NHPI为l0％、Co(acac)2为0．9％时，二苯甲醇的转化率高达97．6％．     

阴离子交换树脂担载氟离子催化合成假性甲基紫罗兰酮

用阴离子交换树脂担载氟离子催化柠檬醛与丁酮的反应,合成了假性甲基紫罗兰。探讨了催化剂用量、反应物配比、反应温度和反应时间等因素对收率的影响,在柠檬醛为100mmol,n(柠檬醛)：n(丁酮)=1：10,催化剂用量为柠檬醛质量的75％,室温反应1h的最佳反应条件下,产物收率87．1％,纯度99．1％。     

H_4SiW_(12)O_(40)/C催化合成丁酮1,2-丙二醇缩酮

以丁酮和1,2-丙二醇为原料,活性炭负载硅钨酸(H4S iW12O40/C)为催化剂,催化合成了丁酮1,2-丙二醇缩酮。正交试验筛选出最佳反应条件为:丁酮200 mmol,n(丁酮)∶n(1,2-丙二醇)=1.0∶1.4,w(催化剂)=1.2%(以反应物质量计),反应时间1 h。在此最佳反应条件下,丁酮1,2-丙二醇缩酮的收率可达71.13%。     

催化氧化合成邻苯二甲醛工艺的响应面优化的研究

以制备的Co/Mo/γ-Al_2O_3为催化剂,采用过氧化氢催化氧化工艺合成邻苯二甲醛,在前期实验基础上,通过响应面法对邻苯二甲醛的合成工艺参数进行了优化,选用Box-Behnken对实验进行设计,研究了对反应有较大影响的反应时间、反应温度及过氧化氢加量三个因素对邻苯二甲醛收率的影响,得到最佳工艺条件并进行模型的建立。实验表明:过氧化氢催化氧化合成邻苯二甲醛的优化工艺条件为:邻苯二甲醇的加量为5g,30%过氧化氢加量15g,反应温度为81℃,反应时间为3h,催化剂为0. 3g,邻苯二甲醛收率可达51. 4%。使用傅里叶红外光谱、核磁共振氢谱、气相色谱对产品结构进行了分析表征。     

咪唑类离子液体在邻苯二甲酰亚胺的N-烷基化反应中的相转移催化作用

研究了1-正丁基-3-甲基咪唑{[BMIM][R],R-[Br],[PF6],[HSO4],[H2PO4]}类离子液体(ILa)在邻苯二甲酰亚胺(1)的N-烷基化反应中的相转移催化作用.考察了ILs的结构及用量、反应温度和反应时间、卤代烃(2)的结构及用量、溶剂等对N-烷基化反应的影响.最佳反应条件为:120mmol,n(1):n(2):n(ILs):n(K2CO3)=1.0:1.5:0.1:1.5,在1,4-二氧六环中于80℃反应3 h,收率86.7%.     

甲苯氧化制苯甲酸的新催化体系

以分子氧为氧化剂,探索了甲苯氧化制苯甲酸的新催化体系,第一次把N-羟基邻苯二甲酰亚胺(NHPI)与钴盐组成的催化剂用于甲苯氧化反应.实验揭示:以NHPI/Co(acac)2(乙酰丙酮酸钴)和NHPI/Co(OAc)2(醋酸钴)为催化剂时,苯甲酸的收率可分别为55.5%与41.2%,文中还对氧气压力、反应温度与时间等对反应的影响进行了讨论,同时提出了可能的反应机理.     

4-氨基-1-丁醇的合成研究

使用四丁基溴化铵为相转移催化剂,以4-氯-1-丁醇作为起始原料,与邻苯二甲酰亚胺钾盐反应制备N-(4-羟基丁基)邻苯二甲酰亚胺(中间产物),中间产物在氢氧化钠的作用下水解得到4-氨基-1-丁醇。通过高分辨质谱、核磁共振谱等对中间产物和产品进行了测定和结构表征。考察了反应溶剂、4-氯-1-丁醇与邻苯二甲酰亚胺钾盐摩尔比、反应温度、反应时间、四丁基溴化铵与邻苯二甲酰亚胺钾盐摩尔比对中间产物收率的影响,优化反应条件之后4-氨基-1-丁醇最佳的总收率为77. 2%。此工艺路线具有合成方法简便、反应条件温和、产品收率高等优点,可以进行工业放大。     

La(OTf)_3催化合成1,3-二噁烷-4,6-二酮化合物的研究

研究了在La(OTf)3的催化条件下,以丙二酸和酮为原料,缩合反应合成了3种1,3-二噁烷-4,6-二酮化合物.考察了酸酮物质的量之比、反应温度、反应时间、催化剂用量及催化剂的稳定性等因素对反应的影响.确定了其最佳反应条件为:取0.1mol丙二酸,n(丙二酸)∶n(酮)=1.0∶1.1,催化剂用量为0.3mol%,反应温度30℃,反应时间为3.0h,在上述反应条件下,产品收率可达62.3%～77.5%.     

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.