The potential utility of polymethylhydrosiloxane (PMHS) as a reducingagent for reductive N-alkylation of aromatic amines and nitrocompoundsusing nitriles as an alkylating agent and Pd(OH)2/C as a catalyst is described. The application of this method for the synthesis of several heterocyclic compounds is also reported.
Design, synthesis, anticoagulant activity evaluation and molecular docking studies of a class of N-ethyl dabigatran derivatives
作者:Weixin Ren、Yujie Ren、Shuai Wang
DOI:10.1016/j.ejmech.2016.05.020
日期:2016.9
A class of N-ethyl dabigatranderivatives was designed based on pharmacological strategies for inhibition of thrombinactivity and the structure-activity relationship studies of the previous dabigatranderivatives. Activities of these novel compounds were predicted based on CoMFA model, and most of the compounds had comparable predicted activity with dabigatran. All of screened compounds were synthesized
基于抑制凝血酶活性的药理策略和以前的达比加群衍生物的结构-活性关系研究,设计了一类N-乙基达比加群衍生物。这些新化合物的活性是基于CoMFA模型预测的,大多数化合物的预测活性与达比加群相当。合成所有筛选的化合物,并通过1 H NMR,13 C NMR和HRMS进行表征。随后,评估了这些化合物对凝血酶的抑制活性。在这些化合物中,9a-9e,9h,9l-9n和9p表现出与达比加群相当的抑制活性(IC 50 = 1.20nM),另外,化合物9p(IC 50 = 0.96nM)表现出比达比加群更好的抑制活性。此外,化合物9p还显示出对动静脉血栓形成的良好抑制活性,抑制率为(85.35±0.72)%,与达比加群(85.07±0.61)%相当。这些结果,以及相关的分子对接研究,可以为化合物9p作为有效的凝血酶抑制剂的进一步开发提供重要的基础。
N–H Insertion reactions of rhodium carbenoids. Part 3.1 The development of a modified Bischler indole synthesis and a new protecting-group strategy for indoles
作者:Katherine E. Bashford、Anthony L. Cooper、Peter D. Kane、Christopher J. Moody、Sendogagounder Muthusamy、Elizabeth Swann
DOI:10.1039/b202666j
日期:2002.7.11
A modified version of the Bischler indole synthesis has been developed in which the key step is the NâH insertion reaction of rhodium carbene intermediates derived from α-diazo-β-ketoesters with anilines. Thus N-methylanilines 1 react with diazoketoesters 2 in the presence of dirhodium(II) acetate to give (N-arylamino)ketones 3, cyclisation of which using boron trifluorideâethyl acetate or acidic ion exchange resin gives the indoles 4. In order to extend this method to the synthesis of N-unsubstituted indoles, a new protecting group strategy for indoles was developed. In this, anilines are reacted with α,β-unsaturated-esters or -sulfones to give the conjugate addition products 6 and 9,
cyclisation of which gives indoles 8 and 11. The N-(2-ethoxycarbonylethyl)- and -(2-sulfonylethyl)- protecting groups are readily removed from indoles 8 and 11 by treatment with base.
Michael Addition Reaction Catalyzed by Imidazolium Chloride to Protect Amino Groups and Construct Medium Ring Heterocycles
作者:Dai、Tian、Li、Shang、Luo、Wang、Li、Zhang、Li、Yuan
DOI:10.3390/molecules24234224
日期:——
An effective approach for amino protection and construction of a seven-membered ring has been developed. The method uses imidazolium chloride to carry out the Michael addition reaction at low temperatures and perform amino deprotection or construction of a seven-membered ring at high temperatures.
trifluoroacetate ([Hmim]TFA) is reported as a cost-effective catalyst for a simple and environmentally benign hetero-Michael reaction. [Hmim]TFA works both as reactionmedium and catalyst. The reaction is applicable to various aromatic sulfur and nitrogen nucleophiles. This method has advantages such as high yields, short reaction time, and simple workup. The catalyst could be recycled several times without any loss