Inverted reactivity of aryllithium derivatives V. On the syntheses of thiocyano-, phenylsulfinyl-, and phenoxy derivatives of thiophenes and furans

The reaction of some diheterocyclic iodonium salts with a variety of nucleophiles has been studied. The reaction was of preparative use for the syntheses of thiocyano, phenylsulfinyl and phenoxy derivatives of thiophenes and furans.     

Synthesis of Thienotriazolopyrimidine Derivatives Containing Triazolothiadiazole Moiety

A series of diheterocyclic compounds 15 and 16 was synthesized by the introduction of 6‐aryl or 6‐benzyl‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazole moiety to thieno[1,2,4]triazolo[4,3‐c]pyrimidine ring through a sulfur linkage.     

Dienamine and Friedel–Crafts One‐Pot Synthesis,and Antitumor Evaluation of Diheteroarylalkanals

An asymmetric synthesis of diheteroarylalkanals through one‐pot dienamine and Friedel–Crafts reaction is presented. The reaction tolerates a large variety of substituents at different positions of the starting aldehyde and also in the indole nucleophile, and a range of diheterocyclic alkanals can be achieved. Furthermore, we have studied the antiproliferative activity of these new compounds in representative cancer tumor cell lines.     

Syntheses of diheterocyclic compounds based on 2-thioacetohydrazide-5,7-dimethyl-1,2,4-triazolo[1,5-a]- pyrimidine

The syntheses of some diheterocyclic compounds from 2-thioacetohydrazide- 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (1) are described. Compound 1 can be converted into triazoles, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles. The structures of the intermediates and the target compounds were confirmed by (1)H-NMR, MS and elemental analyses.     

Copper(II)acetate complexes with piperazine, 1-methylpiperazine, 1,4-dimethylpiperazine and their monohydrochlorides

New copper(II) acetate complexes with the saturated diheterocyclic bases (L-L): piperazine, 1-methylpiperazine, and 1,4-dimethylpiperazine and their monohydrochlorides, have been prepared and characterised by physico-chemical and spectroscopic methods. They are magnetically dilute and antiferromagnetic, with stoichiometries of the type Cu(OAc)₂(B)_n(B=L-L or L-LHCl and n=2, 1 or 0.5).     

Synthesis of 5,7-Dimethyl-2-(5-Substituted-1,3,4-Oxadiazole-2-yl)- Methylenethio-1,2,4-Triazolo[1,5-a]Pyrimidines as Potential Fungicides

New challenging problems in plant protection technology have promoted research to discover more efficient pesticides. In recent years, many chemists have paid much attention to compounds bearing 1,2,4-triazolo [1,5-a] pyrimidine rings due to their broad spectrum of biological activities such as herbicidal and fungicidal effects1-7. Up to now, a great variety of these kinds of compounds have been synthesized, among which some commercially herbicides have been developed including metosulam, f…     

Model studies for the thiol-mediated methyl transfer to corrinoids

The thiol-dependent methylation of heptamethyl cob(II)yrinate 8r with methyl iodide and methyl tosylate was explored under a variety of conditions. The interaction of the heptamethyl cob(II)yrinate with a variety of thiols was monitored prior to the addition of the methylating agent, and the formation of the Co(I) complex was only apparent in the reaction with hexane thiol. Nevertheless, thiol-mediated methylation of the Co(II) complex 8r takes place with methyl iodide under most conditions. The Co-methylation with methyl tosylate showed a different reactivity, was inhibited by pyridine or N-methylimidazole, and was strongly dependent on the the acidity of the thiol used. Mechanistic aspects are discussed.     

Synthesis of 5-(thiazol-5-yl)-4,5-dihydroisoxazoles from 3-chloropentane-2,4-dione

Condensation of 3-chloropentane-2,4-dione with thioamides gives 1-(thiazol-5-yl)ethanones and subsequent Wittig olefination, followed by nitrile oxide 1,3-dipolar cycloaddition to the resulting prop-1-en-2-yl moiety, delivers racemic 5-(thiazol-5-yl)-4,5-dihydroisoxazoles. When this thiazole and isoxazoline diheterocyclic scaffold has a carboethoxy substituent at C2 of the thiazole ring, aminolysis provides for effective diversification. A 50-member library of various 5-(thiazol-5-yl)-4,5-dihydroisoxazoles is reported.     

A microwave‐assisted solid‐state synthesis and characterization of diheterocyclic thioureas

In this study, a number of new diheterocyclic thioureas have been synthesized under microwave irradiation coupled with solvent‐free condition, which proves to be simple and efficient. The structures of the prepared compounds are characterized by elemental analysis, IR, ¹H NMR, and ¹³C NMR spectra. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:148–151, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20193     

An improved and practical route for the synthesis of enzalutamide and potential impurities study

An improved and practical synthesis of enzalutamide was accomplished in five steps. Starting from 4-bromo-2-fluoro-benzonic acid, a methyl esterification, Ullmann ligation, methyl esterification, ring closing reaction and final methyl amidation provided the target in 35% total yield with 99.8% purity. Five identified impurities were also synthesized. This efficient and economical procedure avoids the use of highly toxic reagents and multiple recrystallization operations, which is suitable for further industrialization.     

5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶双杂环衍生物的合成与生物活性

以2-巯基-5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶为原料, 设计合成了17种含5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶环和1,2,4-三唑环的新型双杂环化合物, 结构经元素分析, MS, 1H NMR及13C NMR进行表征. 初步的生物活性测试表明, 部分化合物表现出较好的杀菌、除草活性.     

Calorimetric investigation of polymerization reactions. I. Diffusion-controlled polymerization of methyl methacrylate and styrene

The rate of bulk polymerization of methyl methacrylate and styrene was determined directly, continuously and over the whole range of conversion with a differential scanning calorimeter (DSC) operated isothermally. At the later stages of the accelerated polymerization of methyl methacrylate, a previously unknown inflection or peak in the rate of polymerization was observed. The variation of the rate after the onset of the gel effect, including this peculiar inflection, was interpreted on the basis of the diffusion behavior of monomer molecules and polymeric radicals in the polymer–monomer system, their diffusion rates being predicted from the free volume theory. The final conversion at which no further polymerization proceeds was determined for both monomers. It was affirmed quantitatively that the final conversion has a close relation with the transition of the polymer–monomer system from a viscous liquid to a glassy state.     

Alkoxide-Induced Reaction of 1-[(Trimethylsilyl)-Methyl]Azoles with Imines and Carbonyl Compounds

t-BuOK-induced reaction of 1-[(trimethylsilyl)methyl]-1,2,4-triazole with imines to yield (triazol-1- yl)ethylamines and (triazol-5-yl)methylamines was explored. Also, alkoxide-induced desilylation of 1-[(trimethylsilyl)methyl]azoles in the presence of carbonyl compounds was demonstrated, and (-BuOK and potassium trimethylsilanolate were found to be effective in this reaction.     

Study on the 1,3-dipolar cycloaddition reaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one with nitrile oxides

1,3-Dipolar cycloaddition (1,3-DC) reaction of 4-ethoxy-1,1,1-trifluoro-3-buten-2-one 1 with nitrile oxides was studied. It was found that besides its CC participating in the formation of isoxazole rings, trifluoromethyl activated CO also underwent 1,3-DC reaction with nitrile oxides to afford 1,4,2-dioxazole rings. Single crystal diffraction analysis also evidenced the diheterocyclic configuration.     

甲基丙烯酸甲酯高转化聚合动力学的研究

以金属膨胀计和差热扫描量热计法对甲基丙烯酸甲酯本体聚合的凝胶效应临界转化率和最终转化率与温度、引发剂种类和浓度等聚合条件的定量关系进行了探讨。进一步论证了均相理想聚合体系的最终转化率仅是温度系数。     

STUDIES ON POLYMERIZATION KINETICS OF METHYL METHACRYLATE AT HIGH CONVERSION

The bulk polymerization of methyl methacrylate which was carried out in a metallic dilatometer and in a differential scanning calorimeter has been studied over the complete course of the reaction. An attempt was made to quantitatively express the relation on the onset of gel effect and the final conversion with polymerization conditions such as temperature, kinds and concentration of initiators. It was demonstrated further that the final conversion of polymerization in homogeneous ideal systems is only dependent upon the reaction temperature.     

Efficient Design to Monitor the Site-specific Sustained Release of a Non-Emissive Anticancer Drug

A pH-responsive smart nanocarrier with significant components was synthesized by conjugating the non-emissive anticancer drug methyl orange and polyethylene glycol derived folate moiety to the backbone of polynorbornene. Complete synthesis procedure and characterization methods of three monomers included in the work: norbornene-derived Chlorambucil (Monomer 1), norbornene grafted with polyethylene glycol, and folic acid (Monomer 2) and norbornene attached methyl orange (Monomer 3) connected to the norbornene backbone through ester linkage were clearly discussed. Finally, the random copolymer CHO PEG FOL METH was synthesized by ring-opening metathesis polymerization (ROMP) using Grubbs′ second-generation catalyst. Advanced polymer chromatography (APC) was used to find the final polymer‘s molecular weight and polydispersity index (PDI). Dynamic light scattering, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were utilized to explore the prodrug‘s size and morphology. Release experiments of the anticancer drug, Chlorambucil and the coloring agent, methyl orange, were performed at different pH and time. Cell viability assay was carried out for determining the rate of survived cells, followed by the treatment of our final polymer named CHO PEG FOL METH.     

Unimolecular dissociation of tert-butyl methyl ether via an ion-neutral complex

Ab initio calculations are presented representing the ionization of tertbutyl methyl ether and its subsequent fragmentation via loss of a methyl radical. This process is shown to proceed via an ion-molecule complex, the nature of which is explored. The results obtained are found to be consistent with mass spectrometric evidence.     

Convenient synthesis of dithiafulvene carbene complexes as potential precursors of extended TTF

The condensation of α-carbanion of Fischer-type carbene complex with 2-thiomethyl-1,3-dithiolium salts 1 gave new heterocyclic organometallic carbenes 2 potentially precursors of extended TTF. Reaction of allylic carbanion 4 derived from (methoxypropenyl)pentacarbonyl carbene complex afforded a mixture of monoheterocyclic condensation products 7 and diheterocyclic carbene complexes 8 produced from successive α and γ attacks of the heterocyclic cations.