Efficient combination of task-specific ionic liquid and microwave dielectric heating applied to one-pot three component synthesis of a small library of 4-thiazolidinones

The first report of the use of task-specific ionic liquid as synthetic equivalent of ionic liquid-phase matrice for the preparation of a small library of 4-thiazolidinones is reported in this paper. The starting (ethyleneglycol)ionic liquid-phase is functionalized in good yields with 4-(formylphenoxy)butyric acid by using usual esterification reaction conditions (DCC/DMAP as catalyst). The synthesis of the ionic liquid-phase bound 4-thiazolidinones was performed by a one-pot three-component condensation under microwave dielectric heating. The final cleavage under microwave/catalysis strategy provides the expected 4-thiazolidinones in high purity after flash-chromatography purification. According to the ionic liquid-phase organic synthesis (IoLiPOS) methodology, it was found that optimized reaction conditions were performed by standard analytical methods (NMR, TLC). The ¹H, ¹³C NMR spectrum of some representative 4-thiazolidinones and ionic liquid-phase bound benzaldehyde are also reported.     

Indium (III) Tribromide : An Excellent Catalyst for Biginelli Reaction

A highly efficient catalyst indium (III) tribromide is used to synthesize 5-alkoxy- carbonyl-4-hydrocarbyl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of β-keto ester, aldehydes and urea through improved Biginelli reaction.     

Synthesis of Chiral Cyclohexenones from α-Campholenic,Fencholenic, and β-Campholenic Derivatives

Summary. Optically active dimethylcyclohexenones, potential building blocks for enantioselective syntheses of various naturally active substances, were prepared. These compounds were obtained by oxidation with KMnO₄/Pb(OAc)₄ or ozonolysis of the corresponding cyclopentenic precursors, followed by aldol condensation. During the course of the preparation intermediate diols and chiral polyfunctional carbonyl derivatives were separated and identified analytically.     

有机锡聚醚的合成及性质的研究

利用界面缩聚技术,将二烷基二氯化锡、二(β-烷氧羰乙基)二氯化锡与有机二元醇、酚、硫醇反应,制成了一系列新的有机锡大分子化合物.对这些新化合物进行了分子量、红外光谱、TG/DTG测试.对有机锡大分子化合物阻止聚氯乙烯(PVC)热分解性能进行了测定.结果表明,新合成的有机锡聚醚化合物可作为PVC热稳定剂使用.     

Demonstration of methylene-ether bridge formation in melamine-formaldehyde resins

¹H and ¹³C NMR have been used for the quantitative determination of methylene-ether bridges in melamine-formaldehyde (MF) resins. The amount of methylene-ether bridges was determined by ¹³C NMR from the number of monomethylolated amino groups consumed in the condensation reactions and is in agreement with that calculated from the condensation water contents. This latter method, which involves a combination of ¹H and ¹³C NMR, is based on the amount of condensation water released during the formation of both methylene and methylene-ether bridges. © 1995 John Wiley & Sons, Inc.     

Synthesis of Calix[4]arene Derivatives with NLO Properties

The new chromophore compounds with NLO properties were prepared by Knoevenagel condensation from forrnyl or diformyl calix[4/arene and isophorone derivatives in the presence of piperidine and acetic acid, respectively. In these chromophore calix[4]arenes, the ring locked trienes were employed as the conjugation bridge and electron acceptor in D-π-A units. The NMR spectra demonstrated that they existed in a cone conformation and consequently non-conjugated D-π-A units could be oriented at nearly the same direction.     

1,1,4,4-Tetranitrobutane-2,3-diol and its derivatives. 5. Reaction of 1,1,4,4-tetranitrobutane-2,3-diol with formaldehyde; synthesis and crystal structure of 4,4-dinitro-2,3-dihydroxytetrahydrofuran

1,1,4,4-Tetranitrobutane-2,3-diol reacts with formaldehyde, forming 2,2-dinitropropane-1,3-diol or a cyclic ether — 4,4-dinitro-2,3-dihydroxytetrahydrofuran — as a function of the reaction conditions.Institute of Chemical Physics, Chernogolovka, Russian Academy of Sciences, 142432 Chernogolovka. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2755–2759, December, 1992.     

聚碳酸酯合成工艺开发的新进展

本文从工艺开发的角度，简要评介了目前聚碳酸酯两大工业生产工艺，即光气化界面缩聚工艺和熔融酯交换缩聚工艺的研究开发新动向。     

Synthesis of Derivatives of of Δ2-Imidazolin-5-one and Imidazolidine Containing Residues of Sterically-hindered Phenols

1-Substituted 4-benzylidene-2-{-[3,5-di(tert-butyl)-4-hydroxyphenyl]vinyl}-4-benzylidene-²-imidazolin-5-ones have been synthesized by the interaction of azomethines and N-acylhydrazones (derivatives of 3,5-di(tert-butyl)-4-hydroxybenzaldehyde) with 4-benzylidene-2-methyloxazol-5-one. The acylation of 1,2-bis[3,5-di(tert-butyl)-4-hydroxybenzylideneamino]ethane with acid chlorides in acetonitrile in the presence of triethylamine leads to 1,3-diacyl-2-[3,5-di(tert-butyl)-4-hydroxyphenyl]imidazolidine.     

On the Existence and Hydrolytic Stability of Titanosiloxane Bonds in the System: Glycidoxypropyltrimethoxysilane-Water-Titaniumtetraethoxide

Heterometal materials based on glycidoxypropyltrialkoxysilane and titaniumalkoxide are used for optical applications and require a high homogeneity on the molecular level. The presence of heterometal titanosiloxanes, their distribution and hydrolytic stability should influence the homogeneity of these materials. 29Si and 17O NMR spectroscopy has been used to investigate sols with molar ratios Si : Ti = 1 and H2O : OR (H) = 0.5 – 2.0 and their gels after heat treatment at 130°C. The presence of Si—O—Ti bonds in sols with a low water content (H < 0.2) and in the corresponding gels was identified by the high-field shift of the 29Si NMR signals of T1 and T2 units of up to 2–3 ppm compared to corresponding signals of homo-condensed Si—O—Si bonds. The existence of Si—O—Ti bonds in the sols is supported by 17O NMR spectra which show a characteristic signal around 340 ppm. A cleavage of the Si—O—Ti bonds occurs with increasing water/OR ratio in the sols. The cleavage of the heterometal bonds and the building up of homo-condensed species leads to a separation into areas with predominantly Ti—O—Ti and Si—O—Si bonds resulting in a decreased molecular homogeneity of the materials.