Lanthanide Silylamide-Catalyzed Synthesis of Pyrano[2,3-<i>b</i>]indol-2-ones
作者:Qifa Chen、Yue Teng、Fan Xu
DOI:10.1021/acs.orglett.1c01506
日期:2021.6.18
A lanthanide silylamide-catalyzed tandem reaction of isatins, diethyl phosphite, and 2,3-diarylcyclopropenones has been developed. A series of pyrano[2,3-b]indol-2-ones were synthesized in high yields. The cooperation of the Lewis acidity of the lanthanide center and the Bronsted basicity of the N(SiMe3)2 anion may be the key factor affecting the catalytic activity of lanthanide amides.
已经开发了镧系元素甲硅烷基酰胺催化的靛红、亚磷酸二乙酯和 2,3-二芳基环丙烯酮的串联反应。以高产率合成了一系列吡喃并[2,3 - b ]indol-2-ones。镧系元素中心的路易斯酸度和N(SiMe 3 ) 2阴离子的布朗斯台德碱度的协同作用可能是影响镧系酰胺催化活性的关键因素。
Steric hindrance as a key factor on proton transfer in the σ-adduct forming reactions of o-substituted anilines with 1,3,5-trinitrobenzene in dimethylsulfoxide
作者:Basim H. Asghar
DOI:10.1007/s00706-008-0913-5
日期:2008.10
Kinetic and equilibriumstudies are reported of the reactions of 1,3,5-trinitrobenzene ( TNB ) with a series of o -substituted anilines in dimethyl sulfoxide ( DMSO ) in the presence of 1,4-diazabicyclo[2.2.2.]octane ( DABCO ). The pK a values in DMSO for the aniline derivatives were measured using the proton-transfer equilibrium with 2,4-dinitrophenol. Kineticstudies are compatible with a two-step
Primaryamines are prepared by the electrophilic amination of Grignardreagents with 4,4,5,5-tetramethyl-1,3-dioxolan-2-one O-phenylsulfonyloxime and the acidic hydrolysis of the resulting imines. [reaction: see text]
Thiazole derivatives and medical compositions thereof
申请人:Zenyaku Kogyo Kabushiki Kaisha
公开号:US04804668A1
公开(公告)日:1989-02-14
A thiazole derivative represented by the formula I, pharmaceutically acceptable acid addition salt thereof, and a process for preparation thereof ##STR1## wherein R.sub.1 represents --COOR.sub.4, ##STR2## or cyano wherein R.sub.4 represents hydrogen or lower alkyl, and R.sub.5 and R.sub.6 may be the same or different and represent hydrogen, lower alkyl, aryl, amino-lower alkyl, N-lower alkylamino-lower alkyl, N,N-di-lower alkylamino-lower alkyl or R.sub.5 and R.sub.6 are joined to form a N-containing heterocyclic group; R.sub.2 represents hydrogen or lower alkyl; and R.sub.3 represents N-containing heterocyclic group. These compounds are useful as cardiotonic agents.