Alternating copolymerization of N-(alkyl-substituted phenyl)maleimides with isobutene and thermal properties of the resulting copolymers

Radical copolymerization of N-(alkyl-substituted phenyl)maleimides (RPhMI) with isobutene (IB) was carried out with an initiator in various solvents at 60°C. The copolymerization of N-(2,6-diethylphenyl)maleimide (2,6-DEPhMI) with IB in benzene proceeded readily in a homogeneous system to give an alternating copolymer over a wide range of the comonomer compositions in the feed. Whereas the alternating tendency of the copolymerization of other RPhMI with IB decreased depending on the alkyl substituents of RPhMI in the following order: 2,6-DEPhMI > N-(2,6-dimethylphenyl)maleimide ≥ N-(2-methylphenyl)maleimide >. N-(4-ethylphenyl)maleimide. The copolymerization reactivities were discussed based on the rate constants for the homo-propagations and cross-propagations. Subsequently, the effect of the solvent on the rate and the reactivity ratios was examined. It was revealed that the copolymerization in chloroform proceeded with higher alternating tendency at a higher copolymerization rate than in the copolymerizations in benzene or dioxane. The copolymers of RPhMI with IB showed excellent thermal stability, i.e., high glass transition temperature and initial decomposition temperature over 200 and 350°C, respectively. © 1996 John Wiley & Sons, Inc.     

Synthesis of Pyrazole Derivatives Possessing Anticancer Activity: Current Status

Pyrazole is a versatile lead compound to design potent bioactive molecules for drug discovery and development, particularly in cancer therapy. The aim of this review is to present the most recent deeds in the field of synthetic route made for functionalized pyrazole derivatives active against cell proliferation disease. The review article covers the synthesis of 1H-pyrazole, synthesis of N-substituted pyrazoles, synthesis of pyrazolopyrazoles, and synthesis of pyrazoles fused with a naturally occurring moiety. Some of these reported compounds have passed the preclinical or initial-phase clinical trials for their anticancer activity.     

Six cation-templated halometal complexes and C–H activation of alkylene-bridged azoles

Six dication-templated complexes were discovered in efforts to investigate the effect of linear imidazolium-based template, 1,ω-bis(3,3′-methylimidazolium)alkyl dibromide, on pure inorganic halometal clusters. Complexes {[C₄(Mim)₂](Pb₂I₆)}_n (1) (ω?=?4), {[C₁(Mim)₂] (Ag₂I₄)}_n (2) (ω?=?1), {[C₃(Mim)₂](Ag₂I₄)}_n (3) (ω?=?3), and {[C₄(Mim)₂](Ag₂I₄)}_n (4) (ω?=?4) possess 1-D chain architecture with different organic cations trapped in it. Compound {[C₃′(Mim)₂](CuBr₃)} (5) (ω?=?3) contains the mononuclear anion (CuBr₃)^2? and intra-molecular coupled organic cation with the formed seven-membered ring. {[C₂(Mim)₂S₂]₂(Cu₂I₂)}_n (6) (ω?=?2) presents an infinite 2-D coordination polymer as the first representative polyrotaxane example featuring the biimidazolium thiolate cation ligand. All compounds were further characterized with IR spectra and thermal analysis properties.     

Chirally N-Substituted Indole-2-carbaldehydes. Preparation and Use in Asymmetric Synthesis

A simple method is proposed for the synthesis of optically active indole-2-carbaldehydes via alkylation of 2-cyanoindole by optically active secondary alcohols and subsequent reduction of the cyano group to an aldehyde. Reaction of the aldehydes obtained with aromatic amines gave imines whose reaction with the Danishefsky diene was studied. The structure of the major diastereomer of (2R′)-1-phenyl-2-[1-((1R′)-1-phenylethyl)indol-2-yl]-1,2,3,4-tetrahydropyridine-4-one and minor diastereomer (2S)-2-[1-((1S)-2-methoxy-1-phenylethyl)indol-2-yl]-1-phenyl-1,2,3,4-tetrahydropyridine-4-one respectively were established by X-ray analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1540–1550, October, 2005.     

2,2,4,13,13,15,—六甲基—1,5,12,16—四氮杂环二十二烷—N′,N″′—二乙酸及其镧系配合物的合成和表征

本文合成了题头所示大环配体,并制备了它的十四种镧系元素(La～Lu,Pm除外)固体配合物。用元素分析,DTA-TG,红外光谱以及电导测定等手段研究了这些化合物的组成和性质.基于这些分析结果可建议配合物化学式为Ln(H_2L)(NO_3)_3·nH_2O。     

Cyclization of N-(2,4,6-trimethylphenyl)-β-alanines

Reaction of 2,4,6-trimethylaniline with acrylic and itaconic acids gives the corresponding N-substituted =alanines which can be converted to derivatives of tetrahydropyridone, dihydropyrimidinedione, and 4-carboxy-2-pyrrolidinone. Bromination of the aromatic substituent in the synthesized heterocycles has been carried out.Kaunas Technological University, Kaunas 3028, Lithuania Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 951–954, July, 2000     

Influence of inorganic anions on the tautomeric equilibria of N-substituted aminoazobenzenes — The evidence for ionic association

The influence of inorganic anions: perchlorate, chloride, sulphate, and hydrogen sulphate on the acid-base and tautomeric equilibria of 4-aminoazobenzene (AAB) and its N-ethyl (EAAB), N,N-diethyl (DEAAB), and N-phenyl (PhAAB) derivatives was investigated by UV-spectrophotometry in 80%:20% vol. ethanol:water system. The possible equilibrium models were evaluated by means of the nonlinear confluence analysis program STOICHIO in order to explain the observed dependence of the electronic spectra on acid and salt concentration. It was found that all the anions considered form 1:1 associates with both ammonium and azonium tautomers of the protonated aminoazobenzenes. The corresponding association constants were generally about one order of magnitude greater for SO ₄ ^2– than for the univalent ions. The azonium species were found to form more stable associates in all the cases except SO ₄ ^2– , which explains the observed shift of the tautomeric equilibrium towards the azonium form on increasing the mineral acid or salt concentration. Based on the obtained values of the molar absorption coefficients all but the PhAAB associates were found to be of the ionic pair type, with proton transfer taking place only in the last case. This was due to the greater basicity SO ₄ ^2– , compared with PhAAB. The association constant values obtained are discussed in terms of the tendency of the anions studied to associate, as well as in terms of the effect of solvation on the stability of the ionic pairs formed.     

Synthesis of N-substituted imides via solid-liquid phase-transfer catalytic reaction

Summary N-substituted imides (RSIs) were synthesized from the reactions of alkylbromides (RX) and potassium salts of imides (KSIs) under solid-liquid phase-transfer catalytic conditions (SL-PTC). No water is required in the reaction system. In this work, serious hydration of KSIs is avoided using SL-PTC to synthesize RSIs. The reaction catalyzed by quaternary ammonium salts is greatly enhanced in the solid-liquid solution     

Halogen-containing Pyridines. 8. Synthesis of 3,5-Dichloropyridines Containing Pyrazole and Pyrazoline Residues in Position 2

The interaction of 3,5-dichloro-2-pyridylhydrazine with ,-unsaturated carbonyl compounds leads to 1-(3,5-dichloro-2-pyridyl)-3,5-disubstituted ²-pyrazolines. It was shown that N-(3,5-dichloro-2-pyridyl)hydrazones of the corresponding aldehydes and ketones are formed as intermediates. Condensation of the hydrazine mentioned above with ,-diketones gives 1,3,5-trisubstituted pyrazoles, but with acetoacetic ester a 1,3-disubstituted pyrazol-5-one containing a 3,5-dichloropyridyl residue is obtained.     

N-炔丙基胺类化合物的合成

近五十多年来,科学家们普遍认为是生物体内的自由基的不可逆的氧化导致了生物体生理机能的衰老[1 3]。帕金森症[4]在人群中多发生于老年人。它主要的病理异常是黑质变性,会导致中枢神经纹状体致密区中的多巴胺耗竭。由Ｈｕｅｂ ｎｅｒ[5]等人对Ｎ 炔丙基 Ｎ 取代茚满类化合物所进行的药理作用与其结构关系的研究,发现具有Ｎ 炔丙基的胺类或氨基酸类化合物,对于生物体中单胺氧化酶有较高的抑制作用;而抑制单胺氧化酶,可有效地提高人体大脑中多巴胺的水平[4,6,7]。本文以简便的方法合成了十种尚未见文献报道的Ｎ 炔丙基胺的化合物Ⅰ Ⅹ(表…