制备2,4,6-三甲基苯甲醛的新方法

1,3,5-三甲苯与溴素在水溶液中反应生成2,4,6-三甲基溴苯(1,收率90%);1制备成格氏试剂再与甲醛反应得到2,4,6-三甲基苄醇(2,收率79%)。2经铬酸氧化得2,4,6-三甲基苯甲醛(3,收率90.3%)。3的总收率达64.2%,纯度97%。2和3的结构经1H NMR和MS确证。     

3-仲氨基氧杂环丁烷-3-腈衍生物的合成

以仲胺、氧杂环丁-3-酮和三甲基氰硅烷为原料,无水甲醇为溶剂,无需催化剂,一步反应合成目标化合物3-仲氨基氧杂环丁烷-3-腈衍生物(1a～1d),产物结构经¹H NMR、¹³C NMR和ESI-MS表征。并以异吲哚啉、氧杂环丁-3-酮和三甲基氰硅烷的反应为模型反应,考察影响产物1a收率的主要因素,优化反应条件为:物料摩尔比为n(异吲哚啉)∶n(氧杂环丁-3-酮)∶n(三甲基氰硅烷)=2.0∶1∶2.5;反应溶剂为无水甲醇,在65℃反应6h,在此反应条件下,化合物1a收率78.3%。化合物1a与苯基溴化镁在四氢呋喃中室温反应5h,可得到2-(3-苯基氧杂环丁烷-3-基)异吲哚啉(4)和[3-(异吲哚啉-2-基)氧杂环丁烷-3-基](苯基)甲酮(5),收率分别为40.1%和31.5%。     

三氯化铁催化合成三芳基甲烷化合物的研究

三甲基芳烷类化合物在染料、生物、医药领域具有的重要应用价值。本文研究了2,4,6-三甲基苯甲醛和N,N-二甲基间溴苯胺通过缩合反应制备三芳基甲烷化合物,考察了催化剂种类、反应溶剂、反应温度和反应时间对产物收率的影响。确定合成条件为以无水Fe Cl3作为催化剂、对二甲苯为溶剂、反应温度为128℃,反应时间为32h,目标产物收率达到80%左右,产物结构经质谱和氢核磁共振谱表征确认。     

抗氧化剂1790合成反应的研究

以6-叔丁基-3-氯甲基-2,4-二甲基苯酚和氰尿酸三钠盐为原料,在N,N-二甲基甲酰胺溶剂中合成1,3,5-三(4-叔丁基-3-羟基-2,6-二甲基苄基)-1,3,5-三嗪-2,4,6-(1H,3H,5H)-三酮(抗氧化剂1790),确定较佳的缩合工艺条件。考察了溶剂种类及用量、物料配比、反应温度及时间对反应收率的影响。实验结果表明:在N,N-二甲基甲酰胺溶剂中,反应温度为110℃,反应时间为2.5 h,n(6-叔丁基-3-氯甲基-2,4-二甲基苯酚)/n(氰尿酸三钠盐)=3.2∶1,产品收率为89%,纯度99%(HPLC面积归一化法)。产品结构经IR、MS和~1H-NMR表征。     

3,5-二氯-2,4,6-三硝基苯胺及其衍生物的合成

分别以3,5-二氯苯胺为原料,经N保护、硝化、水解以及以1,3,5-三氯-2,4,6-三硝基苯(TCTNB)为原料,经叔丁胺化,再在三氟乙酸中脱叔丁基2种方法合成了3,5-二氯-2,4,6-三硝基苯胺。 与甲胺反应,合成了3,5-二甲氨基-2,4,6-三硝基苯胺,收率85%,再用混酸硝化合成了3,5-二甲硝胺基-2,4,6-三硝基苯胺的硝酸盐,收率70%。 采用核磁共振、质谱、红外和元素分析等进行了结构表征。 探讨了不同参数下TCTNB的氨化结果。 优化的条件为：n(TCTNB)∶n(叔丁胺)=1∶2,CuO为催化剂,KHCO3为碱。     

三光气法合成盐酸罗哌卡因

以三光气为酰氯化剂,2-哌啶甲酸经酰氯化,酰胺化制得1-N-(2,6-二甲基苯基)-2-哌啶甲酰胺(2),收率50.1%(以2-哌啶甲酸计)。以DMF为溶剂,2经丙基化反应合成了盐酸罗哌卡因(1),收率54%。1和2的结构经1H NMR表征。     

3-苯甲酰基香显素类化合物的合成及胆碱酯酶抑制活性研究

以2,4,6-三甲基苯甲酰氯为原料合成2,4,6-三甲基苯甲酰乙酸乙酯2a.以水杨醛类化合物与苯甲酰乙酸乙酯类化合物,六氢吡啶为催化剂在乙醇中发生环合反应,合成了8个3-苯甲酰基类化合物4a-4h,所有的化合物只需要重结晶纯化,就能得到纯度较高的目标产物.所有目标化合物均经过~(13)C NMR,~(1 )H NMR,ESI-MS对其进行了结构确认.在412 nm处,通过紫外分光光度测定化合物对乙酰胆碱酯酶和丁酰胆碱酯酶的抑制活性.     

3-氯-2,7,7-三甲基双环[41,1]辛-2-烯的酸性重排

用80％硫酸水解3-氯-2,7,7-三甲基双环[4.1.1]辛-2-烯(1)得到芳香族化合物3-甲基-2-苯基丁烷(2),而不是通常所预期的羰基化合物3。文中提出了可能的反应机理。     

N-叔丁氧羰基-3-羟基-1-金刚烷基甘氨酸的合成

以金刚烷甲酸(1)为起始原料,经过酰化,取代,脱羧三步反应一锅法制得金刚烷甲基酮(2),然后氧化甲基得到1-金刚烷基乙醛酸(3),将3与盐酸羟氨反应得到1-金刚烷乙醛酸肟(4),还原4并用BOC酸酐保护氨基得到N-叔丁氧羰基-1-金刚烷基甘氨酸(5),最后经高锰酸钾氧化得到DPP-IV抑制剂沙格列汀中间体N-叔丁氧羰基-3-羟基-1-金刚烷基甘氨酸(6),总收率28%。     

反式-1,2-双[5-取代苯基(口恶)唑-2-基]-乙烯的构象

合成了反式-1,2-双[5-(2,4,6-三甲基苯基)(口恶)唑-2-基]乙烯(1_a),并用分子力学法(MMX程序)计算了标题化合物(POEOP,2,5-二甲基-POEOP及2,4,6-三甲基POEOP).POEOP的结构、构象与X衍射结果颇吻合,分子中2个(口恶)唑环呈稳定的反向排布.比同向排布稳定4.6kJ/mol,旋转能垒约16.8～20.9 kJ/mol.还讨论了标题系列化合物的构象对其紫外光谱的影响.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.