Reactions of <Emphasis Type="Italic">N</Emphasis>-(Polychloroethylidene)arene-and - trifluoromethanesulfonamides with indoles

N-(Polychloroethylidene)arene-and -trifluoromethanesulfonamides reacted with indole and N-substituted indoles to give the corresponding N-[2,2-dichloro(or 2,2,2-trichloro)-1-(1H-indol-3-yl)ethyl]-substituted sulfonamides. Unlike N-(2,2,2-trichloroethylidene)trifluoromethanesulfonamide, less electrophilic N-(poly-chloroethylidene)arenesulfonamides failed to react with 1-(4-nitrophenyl)-1H-indole. Previously unknown N,N’-bis(2,2-dichloroethylidene)biphenyl-4,4’-disulfonamide reacted with 1-benzyl-1H-indole at both azomethine fragments. Likewise, reactions of 1,6-bis(1H-indol-1-yl)hexane and 1,4-bis(1H-indol-1-ylmethyl)-benzene with N-sulfonyl trichloroacetaldehyde imines involved both indole rings in the former.     

Simple one-pot synthesis of 5-(chloromethyl)isoxazoles from aldoximes and 2,3-dichloro-1-propene

Chemistry of Heterocyclic Compounds - A one-pot synthesis of 3-substituted 5-chloromethylisoxazoles from available starting aldoximes and 2,3-dichloro-1-propene, serving both as a solvent and...     

利用一个通用的方法全合成Fuscinarin和Fuscins

通过一个共同的中间体6,首次全合成了fuscinarin (1)和全合成了fuscins,它们都是戊烯酮(pentaketide)的代谢物,在亲近闪烁检测(scintillation proximity assay)中显示具有抗CCR5的活性。这一合成主要是利用微波辅助的 ortho-Claisen/Cope 重排的串联反应更合成中间体10。     

Nonequilibrium dynamics simulations of nitric oxide release: comparative study of nitrophorin and myoglobin

Nitrophorin 4 (NP4) is a heme protein that reversibly binds nitric oxide (NO), with release rates modulated by pH change. High-resolution structures of NP4 revealed that pH changes and NO binding induce a large conformational rearrangement in two loops that serve to protect the heme-bound NO molecule from solvent. We used extended (110 ns) molecular dynamics simulations of NP4 at pH 5 and pH 7, modeled by selective deprotonation of acidic groups. Conformational and dynamic changes were observed, consistent with those found in the crystal. Further, major solvent movement and NO escape were observed at pH 7, while the ligand remained in the heme binding pocket at pH 5. As a control, we also performed molecular dynamics (MD) simulations of sperm whale myoglobin, where NO migration into the interior cavities of the protein was observed, consistent with previous reports. We constructed a kinetic model of ligand escape to quantitatively relate the microscopic rate constants to the observed rates, and tested the predictions against the experimental data. The results suggest that release rates of diatomic molecules from heme proteins can be varied by several orders of magnitude through modest adjustments in geminate rebinding and gating behavior.     

Indole-derived arynes and their Diels-Alder reactivity with furans

Arynes derived from any position of the ubiquitous indole nucleus are unknown. We have now provided the first evidence for the formation and trapping of the 4,5-, 5,6-, and 6,7-indolynes. A series of o-dihalo indoles (Cl, Br, F) were synthesized and reacted under metal-halogen exchange conditions to give Diels-Alder cycloadducts in high yield with furan. The use of an excess of tert-butyllithium resulted in the rearrangement of the initially formed cycloadduct; however, employing only a slight excess of n-butyllithium cleanly gave cycloadducts with furan.     

使用含离子涂层柱的毛细管电泳和毛细管电色谱的研究进展

 毛细管电色谱是近年发展起来的高效、高选择性的微分离技术。与一般的毛细管电泳和使用ODS反相填料的毛细管电色谱相比 ,含离子涂层柱的毛细管电泳和毛细管电色谱能提供较大且可控的电渗流 ,便于拓宽分离对象 ,优化分离条件。对使用含离子涂层柱的毛细管电泳和电色谱的特点、发展和应用状况进行了综述。     

吸光光度法测定鹿茸中锗

鹿茸是一种名贵中药,它能消肿止痛,清热解毒,所以多年被人们广泛使用。锗元素,尤其是有机锗可使人体酶活化,增强细胞活力,促进机体新陈代谢,有抗肿瘤、抗病毒、消炎、延缓衰老和免疫调节等作用Ⅲ。但关于鹿茸中锗含量的测定未见报道,本文用吸光光度法测定了鹿茸中锗的含量,这对该药的研究起到一定的促进作用。     

一种新型MAO改性的高活性铬基气相聚乙烯催化剂

制备了一种新型的CrO3／SiO2／MAO(／EtOAlEt2)乙烯聚合催化剂，在微机控制的自动评价装置上进行了乙烯气相聚合评价试验，研究了催化剂制备中有机铝化合物对催化剂的改性作用．结果表明，MAO作为还原剂可以明显提高催化剂的聚合活性，显著影响乙烯聚合反应动力学，得到的聚乙烯树脂融体流动速率较低．同时采用MAO和EtOAlEt2作为还原剂制备催化剂时，二者具有显著的协同效应，催化剂聚合活性高，临氢效应敏感高，树脂的融体流动速率高．     

Special anticorrosion coatings (sealing pastes) for high-strength steel resistance spot welding

The results of application of new anticorrosion coatings (sealing pastes) during resistance spot welding, which provide for protection of weld joints from corrosive action, are given. The studied anticorrosion coatings (sealing pastes) are proved to allow for flawless weld joints of 30KhGSN2A and Kh15N5D2T steel without degrading their mechanical properties.