Willgerodt–Kindler reaction of arylglyoxals with amines and sulfur in aqueous media: a simple and efficient synthesis of α-ketothioamides

A simple and efficient method for the synthesis of α-ketothioamides via the Willgerodt–Kindler reaction is developed. Reactions were carried out between arylglyoxal hydrates, amines and elemental sulfur in water at 80°C to afford corresponding α-ketothioamides in good to high yields in a short reaction time.     

3,4-Dimethyl-2,5-functionalized thieno[2,3-b]thiophenes: versatile precursors for novel bis-thiazoles

Synthesis of novel bis(thiazoles) 19–22, 24, 25, 30 and 31 is reported. Thus, reaction of the bis(α-bromoketones) 14 and 15 with the corresponding thioamide derivatives 16–18 in refluxing EtOH in the presence of triethylamine afforded 19–22 in good yields. On the other hand, the novel bis(thiazoles) 24 and 25 can be synthesized by the reaction of 14 and 15 with the corresponding p-chlorobenzaldehyde thiosemicarbazones 23 in refluxing EtOH. The novel isomeric bis(thiazoles) 30 and 31 can also be synthesized by a reaction of the corresponding bis(benzaldehyde thiosemicarbazones) 27 and 28 with p-chlorophenacyl bromide 29. Compounds 27 and 28 were obtained by condensation of the corresponding bis(aldehydes) 12 and 13 with thiosemicarbazide 26.     

A convenient [hydroxy(tosyloxy)iodo]benzene-mediated one-pot synthesis of 2-arylimidazo[2,1-b]benzothiazoles

Several 2-arylimidazo[2,1-b]benzothiazoles (4) have been conveniently synthesized in one-pot reactions via α-tosyloxylation of enolizable ketones (1) using [hydroxy(tosyloxy)iodo]benzene 2 in acetonitrile, followed by treatment with 2-amino-6-(substituted)benzothiazoles (3). The present protocol offers several advantages towards general access of 2-arylimidazo[2,1-b]benzothiazoles, including an intriguing alternative to the literature protocols, a readily available nontoxic reagent, operational simplicity and an environmentally benign procedure.     

SYNTHESIS,RHEOLOGICAL BEHAVIOR,AND MECHANICAL PROPERTIES OF GRAFT-TYPE ACS RESIN

Graft-type ACS resin and α-methylstyrene (α-Mst)-containing ACS were synthesized by suspension polymerization. The effect of concentration of initiator and polyvinyl alcohol (PVA) on reaction was discussed. The graft efficiency (GE) increased with the increasing concentration of initiator in the first stage, but it began to decrease when the initiator concentration exceeded 3.3–3.5×10^?4mol L^?1. The GE decreased gradually with the increasing concentration of PVA. The rheological behavior, mechanical properties, and morphological structure of resins were studied. The rheological behavior became worse with the increasing content of chlorinated polyethylene and the melt is a pseudo-plastic liquid. The impact strength of graft-type ACS resin increased as the content of chlorinated polyethylene increased. The rheological behavior and impact properties of α-Mst-containing ACS resin got better because of the introduction of α-Mst, and the comprehensive properties was the best at the 5% α-Mst content of ACS resin.     

α-甲基苯乙烯和苯乙烯共聚物乳液的合成及性能研究

在不通N2的条件下,采用半连续法,在85℃、乳化剂用量为总量的7.53%时合成出了不同单体配比的α-甲基苯乙烯-苯乙烯共聚物[P(AMS-St)]乳液,其中AMS单体含量最高可达70%以上。用红外、核磁对共聚物结构进行了表征,讨论了加料方式、反应温度、乳化剂用量、单体配比对乳液转化率及稳定性的影响和单体组成与乳液流变性、乳胶粒径大小之间的关系。结果表明随单体中AMS含量的增加,乳液黏度逐渐变大,乳胶粒径逐渐变小,乳胶粒具有均一的尺寸。     

AMS加氢制异丙苯反应动力学及机理

用α-甲基苯乙烯（AMS）在自制Pd/γ-Al₂O₃催化剂上加氢生成异丙苯，于间歇搅拌釜内研究了该反应的本征动力学，在排除内外扩散影响的前提下，分别在不同温度、氢压、原料浓度下测定了反应级数，分析了反应机理。结果表明，该反应对氢为一级，而对AMS为变级数反应。     

竞争性抑制剂对反胶团萃取过程中α胰凝乳蛋白酶活力的稳定作用

研究了竞争性抑制剂苯基硼酸对a胰凝乳蛋白酶反胶团萃取过程的影响及对酶活力的稳定作用. 研究发现,向AOT/isooctane 反胶团中添加一定量的苯基硼酸,萃取率会略有增加,反萃取率则无显著变化. 酶活力的回收率显著提高,酶活力对萃取和反萃时间的耐受性显著增强. 苯基硼酸和a胰凝乳蛋白酶之间的特异性亲和作用是产生这种影响的原因.     

α,β-不饱和酮与金属有机试剂的不对称共轭加成反应的研究进展

综述了近来α,β 不饱和酮与金属有机试剂的不对称共轭加成反应的研究进展。详细介绍了α,β 不饱和酮与金属试剂反应的配体及影响反应的条件。     

Investigation on the early and late stage phase-separation dynamics of poly(methyl methacrylate)/poly(α-methyl styrene-co-acrylonitrile) blends through rheological and scattering functions

The phase-separation behavior of poly(methyl methacrylate)/poly(α-methyl styrene-co-acrylonitrile) (PMMA/α-MSAN) blends with two different compositions was studied by time-resolved small angle light scattering (SALS) in the spinodal decomposition (SD) regime from 160 to 210 °C. The rheological function (WLF-like equation) was introduced into the processing of light scattering data. It was found that the WLF-like equation was applicable to describe the temperature dependence of apparent diffusion coefficient D_app and the relaxation time τ of normalized scattering intensity (I(t)−I(0))/(I_m−I(0)) at the early stage of SD, as well as the relaxation time τ of maximum scattering intensity I_m and characteristic scattering vector q_m with I_m at the late stage of SD for PMMA/α-MSAN blends with two different compositions. This is in consistence with the phase-separation behavior of PMMA/SAN reported in our previous paper.     

Evaluation of vitamin E by HPLC in a variety of olive-based foodstuffs

A survey of vitamin E levels in a wide variety of olive-based foodstuffs was conducted. Vitamin E was determined by normal-phase HPLC. The only form of vitamin E found in all commercial presentations of table olives was α-tocopherol, with an average content of 3.1 mg/100 g edible portion. A very low content (<0.4 mg/100 g edible portion) of γ-tocopherol was found in most of the samples analyzed. The main sources of variation of vitamin E were olive cultivars and commercial presentations. Processing type (Spanish style green olives, directly brined olives, ripe olives) had a limited influence. Irrespective of the elaboration style, the Gordal cultivar was the poorest with respect to the vitamin E content. On the other hand, all commercial presentations based on the Hojiblanca cultivar had high contents of vitamin E. The results of this study may be used by the industry for requirements of nutritional labeling or by nutritionists to estimate vitamin E intakes in diets that include table olives.