Na2S-mediated thionation: an efficient access to secondary and tertiary α-ketothioamides via Willgerodt–Kindler reaction of readily available arylglyoxals with amines

The task of this paper is to provide an efficient process for synthesis of secondary and tertiary α-ketothioamides via Willgerodt–Kindler reaction of readily available arylglyoxals with amines using Na₂S as an effective catalyst. A plausible role for Na₂S in the reaction of arylglyoxals with primary amines is proposed.     

溴化铜对乙酰基愈创木酚的选择性溴化反应

以愈创木酚为起始物,合成了4-乙酰基愈创木酚,然后以4-乙酰基愈创木酚和溴化铜(CuBr2)为反应物,分别用乙酸乙酯与三氯甲烷的混合溶液、甲醇、乙醇作为反应溶剂合成了4-(α-溴代乙酰基)-愈创木酚,并利用红外光谱、核磁共振谱(1H-NMR)等手段对其化学结构进行了分析和确认。研究结果表明,利用甲醇和乙醇作为反应溶剂,将该4-乙酰基愈创木酚的取代反应由非均相转变为均相,得率稳定在90%以上。该溴代反应受反应时间的影响不大。重结晶的方法不能将产物分离,采用硅胶层析用乙酸乙酯和正己烷(1∶2,V/V)作为流动相可分离得到产物。     

几种4-α-呋喃甲酰PMP希夫碱的合成与抑菌活性研究

合成了1-苯基-3-甲基-4-(a-呋喃甲酰基)-吡唑啉酮-5(4-a-呋喃甲酰PMP)及其三个双希夫碱和两个单希夫碱。通过元素分析、红外、紫外吸收光谱分别表征了它们的分子结构。采用琼脂扩散滤纸片法测定了几种希夫碱对大肠杆菌、酒精酵母菌、黑曲霉菌、腾黄八叠球菌、腾黄微球菌和枯草芽孢杆菌的抑菌活性,结果表明:几种希夫碱对除黑曲霉菌外的受试菌均有一定抑制作用。     

Investigation of the effect of branched structure on the performances of the copolymers synthesized from ethylene and α-olefin with rac-Et(Ind)2ZrCl2/MMAO catalyst system

The branched copolymers prepared from ethylene and α-olefins using rac-Et(Ind)₂ZrCl₂/MMAO catalyst system were studied. Both the absolute molecular weight and the molecular size (radius of gyration, R_g) of the polymers eluting from gel permeation chromatography (GPC) columns were obtained simultaneously via a high temperature GPC coupled with a two-angle laser light scattering (TALLS) detector. The branched structures and performances of the copolymers display approximate molecular weight and molecular sizes were investigated. Wide angle X-ray diffraction analyses indicate that 16-carbon side branch could co-crystallize effectively with backbone chain at low α-olefin incorporation. The melt behaviors of the copolymers were studied by dynamic rheological measurements. Both branch length and comonomer content affect considerably the loss modulus, storage modulus and complex viscosity of the copolymers. The relationship between the dynamic-mechanical behavior and the comonomer content of the copolymers was also examined by dynamic-mechanical experiments. It is found that the intensity of β-transition raise with comonomer content increasing.     

Novel triblock copolymers synthesized via radical telomerization of N-isopropylacrylamide in the presence of polypseudorotaxanes made from thiolated PEG and α-CDs

A protocol for the preparation of novel triblock copolymers comprising a polyrotaxane center block and outer blocks of poly(N-isopropylacrylamide) (PNIPAAm) as bulky stoppers was developed, in which N-isopropylacrylamide was allowed to telomerize in the presence of polypseudorotaxanes made from the self-assembly of thiol end-capped PEG with a varying amount of α-CDs under UV irradiation in aqueous solution. The molecular structure of the resulting copolymers was characterized in detail by ¹H NMR, FTIR, XRD, TG and DSC analyses. It was demonstrated that the PNIPAAm blocks are successfully attached to the two terminals of the polypseudorotaxanes and each block having the minimum 7 NIPAAm units seems long and bulky enough to efficiently impede the dethreading of α-CDs from the PEG axle to give rise to the triblock polyrotaxane-containing copolymers.     

GPC净化高效液相色谱法测定肉制品中的苯并（α）芘

目的：建立肉制品中的苯并（α）芘的检测方法。方法：肉制品经超声提取后,提取液经GPC分离净化,浓缩后用乙腈定容经高效液相色谱分离,荧光检测器测定,外标法定量。结果：方法线性关系良好,加标回收率为87.5%～95.4,相对标准偏差小于5%,检出限为0.1μg/kg。结论：本法前处理简便,定量准确可靠,适用于肉制品中苯并（α）芘的测定。     

苯妥英钠对鼠脑缺血再灌注时血浆细胞因子及内皮素的影响

目的 探讨苯妥英钠对脑缺血再灌注后TNFα、IL-Ⅰβ 和ET₁的影响。方法 采用线栓法制备大鼠局灶性脑缺血再灌注模型, 用放射免疫方法检测脑缺血再灌注大鼠血浆TNFα、IL-Ⅰβ、ET₁的变化, 以及苯妥英钠对TNFα、IL-Ⅰβ、ET₁ 含量的干预作用。结果 缺血再灌组与假手术组相比, 血浆TNFα、IL-Ⅰβ、ET₁ 含量明显增加, 应用苯妥英钠各剂量组TNFα、IL-Ⅰβ、ET₁水平均降低。结论 TNFα、IL-Ⅰβ、ET1 参与了局灶性脑缺血再灌注损伤的病理过程, 苯妥英钠通过降低TNFα、IL-Ⅰβ、ET₁ 的含量能发挥一定的脑保护作用。     

IN SITU OBSERVATION ON FORMATION OF BASKET DURING BAINITIC TRANSFORMATION

By means of riM-190 hot-stage microscopy,the in situ observation of α-β transformation in12Cr2MoWVTiB steel has been carried out.The sequence of the growth of ferritic needlescomposing bainitic basket has also been determined.According to the crystallographic analy-sis a multislip system transform model concerning the formation of basket has been proposed.     

ON THE ORDERING TRANSFORMATIONS IN Ti_3AL-Nb ALLOY

Study was made of the behaviour of ordering transformation in Ti_3AI-Nb alloy,including the ordering at high temperatures,the transformation of high temperature β-phase during cooling,and the decomposition of metastable β-phase during aging.The results show that the ordered primary α_2 and high temperature β in alloy form at 1060℃.The transformation of high temperature β-phase proceed by β→α_2+ω type during cooling,and the decomposition of metastable β and ω type proceeded by(β+ω)_(metustabte)→(α_2+β)_(stable)during aging at 700℃.     

HPLC-DAD及HPLC-MS研究干燥工艺对中药粗榧化学成分的影响

用高效液相色谱-二极管阵列检测器及高效液相色谱-质谱联用技术,发现常压及减压干燥能使粗榧提取物中两个主要的化合物(1号峰和2号峰)发生降解。减压干燥后两个化合物分别减少了20.2%和45.6%,常压干燥后,两个化合物均检测不到。与干燥前相比,减压干燥和常压干燥使3号峰面积分别增加了1.90倍和5.74倍。1~3号峰均具有特征性的黄酮化合物的两个紫外吸收带(240~280 nm和300~400 nm),被推测为黄酮化合物,质谱研究推测1~2号峰发生了苷键断裂生成3号峰。用AB-8大孔吸附树脂,葡聚糖凝胶LH-20,反相硅胶(ODS)柱色谱分离纯化得到1~3号峰的3个化合物,对其进行了红外和核磁测定,鉴定出芹菜素-5-O-α-L-吡喃鼠李糖基(1→4)-β-D-吡喃葡萄糖苷和芹菜素-5-O-α-L-吡喃鼠李糖基(1→4)-6″-O-乙酰基-β-D-吡喃葡萄糖苷两个黄酮苷,干燥过程使它们苷键断裂生成了苷元芹菜素(3号峰)。