Reactions of electron-rich heterocycles with orthocarboxylic acid derivatives. 11. Reactions of carbazole and 4-methoxycarbazole with triethyl orthoformate: Regiospecific functionalization of the carbazole nucleus

Carbazole ( 1a ) and 4-methoxycarbazole ( 1b ) can be regioselectively functionalized by reaction with triethyl orthoformate. Whereas the reaction of 1a with the ortho ester furnishes the amide acetal 2 , the new carbazole derivatives 4–10 are formed, depending on the reaction conditions, in the electrophilic substitution of 1b . The products of this reaction sequence provide a contribution to studies on the mechanism of the transformation of 1b to tris-carbazolylmethane 5 . Compound 5 represents a new, three-bladed propeller in the triheteroarylmethane series.     

Expeditious access to the most easily ionized closed-shell molecule, W2(hpp)4

A new synthetic path, far superior to either of those previously available, to the W2(hpp)4 molecule (Hhpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) is reported. The reaction of W(CO)6 with Hhpp in o-dichlorobenzene at 200 degrees C produces W2(hpp)4Cl2 in a one-pot reaction in over 90% yield. This compound is stable and easily stored for further use, and it can be efficiently reduced in a one-step reaction to the title compound W2(hpp)4.     

New ab initio potential energy surface and quantum dynamics of the reaction H(2S) + NH(X3Σ-) → N(4S) + H2

A new global potential energy surface is reported for the ground state ((4)A(")) of the reaction H((2)S) + NH(X(3)Σ(-)) → N((4)S) + H(2) from a set of accurate ab initio data, which were computed using the multi-reference configuration interaction with a basis set of aug-cc-pV5Z. The many-body expansion and neural network methods have been used to construct the new potential energy surface. The topographical features of the new global potential energy surface are presented. The predicted barrier height is lower than previous theoretical estimates and the heat of reaction with zero-point energy is closer to experimental results. The quantum reactive scattering dynamics calculation was carried out over a range of collision energies (0-1.0 eV) on the new potential energy surface. The reaction probabilities, integral cross-section, and rate constants for the title reaction were calculated. The calculated rate constants are in excellent agreement with the available experimental results.     

Synthesis of new 1-substituted 4-(2-phenylquinazolin-4-yl)-and 4-(2-phenylquinazolin-4-ylidene) thiosemicarbazides

Two new 1-substituted 4-(2-phenylquinazolin-4-yl)-and 4-(2-phenylquinazolin-4-ylidene) thio-semicarbazides were formed by a multistep domino reaction of imidoyl isothiocyanate derivative with 1,1-di-R-hydrazine in acetone solution. Application of hydrazine hydrate under the same reaction conditions afforded 4-(2-phenylquinazolin-4(3H)-ylidene)-2-(propen-2-yl)-1-(propan-2-ylidene) thio-semicarbazide via a six-step triple-component domino reaction. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1688–1693, November, 2008.     

Kinetic study of dichlorocyclopropanation of 4-vinyl-1-cyclohexene by a novel multisite phase transfer catalyst

In this work, the dichlorocyclopropanation of 4-vinyl-1-cyclohexene catalyzed by a new novel phase transfer catalyst was carried out in an alkaline solution/chloroform two-phase medium. This new synthesized phase transfer catalyst, 1,4-bis(triethylmethylammonium)benzene dichloride (DC-X), which possesses two-site activity, was obtained from the reaction of ,′-dichloro-p-xylene and triethylamine. This new novel phase transfer catalyst exhibits higher reactivity than those of the other quaternary ammonium salts. The reaction of chloroform and alkali was carried out at the interface to generate dichlorocarbene which can further react with 4-vinyl-1-cyclohexene to produce mono-dichlorocyclopropane and bis-dichlorocyclopropane products. Rational mechanism of the dichlorocyclopropanation is proposed according to the experimental evidence. The reaction follows a pseudo-first-order rate law. Kinetics of the reactions such as: effect of the catalysts, agitation speed, temperature, alkaline concentration, amount of DC-X catalyst, amount of 4-vinyl-1-cyclohexene (reactant) and volume of chloroform (organic solvent) on the reaction rate were investigated in detail. Peculiar phenomenon for the dependence of the reaction rate on the amount of DC-X catalyst is explained satisfactorily.     

9,9-二[4-(4-羧基苯氧基)苯基]呫吨的合成

在碘化亚铜、四丁基溴化铵和磷酸钾存在下,9,9-二(4-羟基苯基)呫吨(1)和4-甲基碘苯(2)于N,N-二甲基甲酰胺溶剂中发生Ullmann偶联反应,加热回流反应24 h,以95%的产率合成了中间体--9,9-二[4-(4-甲基苯氧基)苯基]呫吨(3),继而加入催化量的N-溴代丁二酰亚胺并在光照条件下,将中间体3氧化得到一种新型芳香族二羧酸--9,9-二[4-(4-羧基苯氧基)苯基]呫吨(4),其产率为84%,二步反应总收率为79.8%。 目标化合物4经1H NMR、13C NMR、IR和元素分析测试技术确定了其结构。 该法具有原料易得,操作简单,反应条件温和,收率高等优点。     

Dakin反应的研究

本文对九个酚醛及酚酮类化合物的Dakin反应进行了研究。由于避免了过度的氧化和副反应,所以产率较文献报道的60～80％要高,可达81～96％。其中,2-甲酰基雌酚酮和4-甲酰基雌酚酮的Dakin反应尚未见报道,产率几乎是计算量的。采用本文的方法,可将Dakin反应由通常的甲酰基或乙酰基成功地扩展应用到含丙酰基的酚酮。     

新型结构规整的三联苯桥基四官能度化合物的合成与表征

以对-溴甲苯、对苯二酚、1-溴己烷、1,4-对苯二异氰酸酯等为原料, 通过Williamson反应、溴化反应、格氏反应、氧化反应、Suzuki反应等一系列反应合成了用于合成梯形聚合物的两种重要单体: 2,5-二[4′-N-(1,1-二羟甲基)丙胺基甲酰苯基]-1,4二己氧基苯和2,5-二｛4′-N-[1,1-二(对异氰酸酯基苯胺甲酸酯基)丙胺基甲酰苯基]｝-1,4二己氧基苯, 并利用元素分析、红外光谱(IR)、核磁共振氢谱(¹H NMR)和质谱(MS)等手段对其进行了结构表征.     

α-碳基—硫代半缩醛与脂肪族脲反应合成2,4-咪唑啉二酮衍生物

利用α-羰基—硫代半缩醛与脂肪基取代脲反应合成了六个新的咪唑啉二酮类衍生物,并用IR,NMR,MS和元素分析进行测定,最后用X四圆衍射仪确定了它们的结构.     

─硫代半缩醛的反应研究──1-苯甲酰基-1-甲硫基甲醇与脲的反应

一硫代半缩醛非常活泼,不易分离得到．但当在其邻位导人一个谈基后所生成的a一谈基一硫代半缩醛就比较稳定,且能够分离得到［’·’j．我们首次研究了a一拨基一疏代半缩醛如卜苯甲酸基一1一甲硫基甲醇（2）与尿素（3a）或芳基晚（3b—3g）的反应,发现在弱酸性条件下可?..     

Stereoselective synthesis of functionalised carbocyclic amides: construction of the syn-(4aS,10bS)-phenanthridone skeleton

A new synthetic approach has been developed for the preparation of 7-deoxypancratistatin analogues bearing a syn-(4aS,10bS)-phenanthridone ring junction. A one-pot tandem process involving a substrate-directed Overman rearrangement and ring closing metathesis reaction was developed for the stereoselective synthesis of a carbocyclic allylic trichloroacetamide. Conversion to a 6-bromopiperonyl amide, followed by a Heck reaction generated a homoallylic alcohol and completed the syn-(4aS,10bS)-phenanthridone carbon skeleton. Stereoselective epoxidation and dihydroxylation of the syn-(4aS,10bS)-phenanthridone framework was then investigated leading to the preparation of new analogues of 7-deoxypancratistatin.     

Synthesis and molecular structure of new acyclic analogues of nucleotides with a 1,2-alkadienic skeleton

Reaction of 1-chloro-4-(diethoxyphosphonyl)alka-2,3-dienes 14,15 with purine and pyrimidine heterocyclic bases in the presence of cesium carbonate afforded new acyclic analogues of nucleotides containing a 1,2-alkadienic skeleton 18-23. Dealkylation of 18-23 furnished phosphonic acids 2a-f. In contrast, alkylation reaction with 1-chloro-4-(diethoxyphosphonyl)octa-2,3-diene 16 led to Z- and E-1,3-alkadienic phosphonates 25a,b and 26a,b. A similar reaction with 1-chloro-4-(diethoxyphosphonyl)-2-methylbuta-2,3-diene 17 led to the elimination of hydrochloride and formation of 4-(diethylphosphonyl)-2-methylbut-1-en-3-yne 24. Molecular structures of new acyclic nucleotides 18 and 2f are determined by X-ray crystallographic analysis.     

α-羰基一硫代半缩醛与脂肪族脲反应合成2, 4-咪唑啉二酮衍生物

利用α-羰基一硫代半缩醛与脂肪基取代脲反应合成了六个新的咪唑啉二酮类衍生物。并用IR,NMR,MS和元素分析进行测定,最后用X四圆衍射仪确定了它们的结构。     

乙烯／顺丁烯二酸酐共聚物为主链的光致变色苯氧基萘并萘醌聚合物

通过由３－溴丙－１－醇（１）与６－［４－（２－（４－羟基苯基）异丙基）苯氧基］－５,１２－萘并萘醌（２）反应制备新反应试剂６－［４－（２－（４－（３－羟基丙氧基）苯基）异丙基）苯氧基］－５,１２－萘并萘醌（３）,然后通过（３）与乙烯－顺丁烯二酸酐交替共聚物反应的方法成功合成了乙烯－顺丁烯二酸酐为主链的光致变色苯氧基萘并萘醌聚合物（４）。与化合物（２）相似,聚合物（４）具有正常的光致变色行为。同时发现,溶剂对聚合物（４）和化合物（２）的光诱导ｔｒａｎｓ→ａｎａ异构化反应速度有明显影响。在ＴＨＦ／Ｈ２ＳＯ４（Ｖ／Ｖ＝２４／１）中的速度常数约为在ＤＭＳＯ／Ｈ２ＳＯ４（Ｖ／Ｖ＝２４／１）中的速度常数的两倍     

Phosphine-catalyzed synthesis of 1,3-dioxan-4-ylidenes

[reaction: see text] A phosphine-catalyzed reaction of an allenoate with aldehydes furnished (2,6-diaryl-[1,3]dioxan-4-ylidene)-acetates 4 in excellent to moderate yields with complete diastereoselectivity and high E/Z-selectivities. Upon removal of the acetal functionality in this domino reaction product 4, delta-hydroxy-beta-ketoester 11 was obtained. The reported vinylphosphonium-based approach provides a new way to achieve a synthesis of delta-hydroxy-beta-ketoesters that differs from the classical dianion-based approach.     

β-CD-Shiff碱铜(Ⅱ)配合物模拟酶催化光度法的研究

合成了Shiff碱2-羟基-1-萘醛缩-2-氨基噻唑(HNATS)及其铜配合物,发现配合物Cu(Ⅱ)-(HNATS)~2具有显著的过氧化物模拟酶活性,可催化H~2O~2氧化4-氨基安替比林与2,4-二氯苯酚偶联反应。研究了β-环糊精对模拟酶催化活性的影响,探讨了反应机理,考察了反应条件和共存物质的影响,建立了新的测定超氧阴离子自由基(O~2^-^.)的分光光度法,线性范围为0～5.0×10^-^4mol/L,检出限为5.0×10^-^6mol/L。方法用于测定人体血液中超氧化物歧化酶(SOD)活性,结果满意。     

4-（4′-甲氧基-苯基）亚甲基-1h-咪唑啉-5-酮类schiff碱的合成与生物活性

咪唑啉酮;schiff碱;串联aza-wittig反应;合成;生物活性     

Synthesis and Characterization of Poly(ether amide)s Containing Phthalazinone Moieties

Soluble aromatic polyamides containing phthalazinone moieties were prepared. Those polymers were obtained from the solution polymerization of a new diacid containing phthalazinone moieties with various diamines. The new monomer, 2-(4-carboxyphenyl)-4-(4-carboxyphenoxy)phenyl-1(2H)phthalazinone(Ⅳ) was synthesized in a two-step reaction sequence. 2-(4-Cyanophenyl)-4-(4-cyanophenoxy)phenyl-1(2H)phthalazinone (Ⅲ) was prepared via the condensation reaction of 4-(4-hydroxyphenyl)-1(2H)phthalazinone (Ⅰ) with p-chlorobenzonitrile (Ⅱ). After (Ⅲ) was hydrolyzed, (Ⅳ) was acquired. The synthesized polyamides were characterized by means of viscosimetry, DSC, FT-IR, 1H NMR and EA. The polyamides have a high glass transition temperature which can be as high as 316 ℃. The polyamides also have good solubilities in some organic solvents.     

Nucleophilic substitution reactions of 1,4-dichlorobenzene chromium tricarbonyl with mono- and diphenoxides

The nucleophilic substitution reactions of 1,4-dichlorobenzene chromium tricarbonyl ( 1 ) with the phenoxide anion were investigated. The substitution of the first chlorine was very fast and gave the mono-substituted product in high yield. The substitution of the second chlorine group was significantly retarded by the presence of the phenoxy group incorporated during the first reaction and also due to the competing decomplexation reaction. The application of 1,4-dichlorobenzene chromium tricarbonyl ( 1 ) to the synthesis of new monomers was demonstrated by the preparation of 2,2′-bis[4-(4-chlorophenoxy)phenyl]propane ( 9 ). 2,2′-Bis[4-(4-chlorophenoxyl)phenyl]propane ( 9 ) was synthesized by a nucleophilic substitution reaction of 4,4′-isopropylidenediphenolate with 1,4-dichlorobenzene chromium tricarbonyl ( 1 ) followed by decomplexation with I₂. 2,2′-Bis[4-(4-chlorophenoxy)-phenyl]propane ( 9 ) was also synthesized via a three-step reaction starting from the nucleophilic substitution reaction of 4,4′-isopropylidenediphenol ( 7a ) with 1-chloro-4-nitrobenzene ( 10 ). 2,2′-Bis[4-(4-chlorophenoxy)phenyl]propane ( 9 ) was polymerized by a Ni(0)-catalyzed reaction to yield amorphous aromatic polyethers with number-average molecular weights of up to 11,200 g/mol. © 1993 John Wiley & Sons, Inc.     

Synthesis and Characterization of new Monomers and Polymers Containing Hindered Piperidine Groups

Abstract

Two new methacryloyl ureas, 1-(2-methylacryloyl)-3-(2,2,6,6-tetra-methylpiperidin-4-yl)-urea and 1-butyl-3-(2-methylacryloyl)-1-(2,2,6,6-tetramethylpiperidin-4-yl)-urea (monomer I and monomer II), were prepared by the addition reaction of 2-methylacryloyl iso-cyanate with 2,2,6,6-tetramethylpiperidin-4-yl-amine or butyl-(2,2,6,6-tetramethylpiperidin-4-yl)-amine in a molar ratio of 1:1 at low or room temperature. In a similar way, the syntheses of two new methacryloyl carbamates, 1-(2,2,6,6-tetra-methylpiperidin-4-yl)-3-(2-methylacryloyl)-carbamate and l-(1,2,2,6,6-pentamethyl-piperidin-4-yl)-3-(2-methylacryloyl)-carbamate (monomer III and monomer IV), were completed by the reaction of 2,2,6,6-tetra-methylpiperidin-4-ol or 1,2,2,6,6-pentamethylpiperidin-4-ol with 2-methylacryloyl isocyanate in the presence of dibutyltin dilaurate as catalyst at 60°C. The four new monomers were homopolymerized, and copolymerized with styrene by AIBN as initiator at 70°C. The structures of the new monomers and their polymers were characterized by FT-IR and NMR spectroscopy and by GPC.