‘One-pot’ synthesis of 4-substituted 1,5-diaryl-1H-pyrazole-3-carboxylates via lithium tert-butoxide-mediated sterically hindered Claisen condensation and Knorr reaction
作者:Jian-An Jiang、Wei-Bin Huang、Jiao-Jiao Zhai、Hong-Wei Liu、Qi Cai、Liu-Xin Xu、Wei Wang、Ya-Fei Ji
DOI:10.1016/j.tet.2012.11.012
日期:2013.1
A concise ‘one-pot’ synthesis of a variety of 4-substituted 1,5-diaryl-1H-pyrazole-3-carboxylates has been developed in moderate to good yields with excellent regioselectivity. Less cost lithium tert-butoxide has been identified as a base for sterically hindered Claisencondensation to efficiently generate the labile 3-substituted 4-aryl-2,4-diketoesters. Furthermore, extensive studies lead to a ‘one-pot’
Synthesis, spectral studies and tritiation of the cannabinoid antagonist SR141716A
作者:Herbert H. Seltzman、F. Ivy Carroll、Jason P. Burgess、Christopher D. Wyrick、David F. Burch
DOI:10.1039/c39950001549
日期:——
An efficient synthesis of the cannabinoid antagonist SR141716A is presented and the structure is established by nOe experiments; tritiated SR141716A is synthesized by a novel sequence of metallation–iodination–tritiation and the labelled site is shown by tritium NMR and tritium–hydrogen nOe experiments.
A process for preparation of Pyrazole derivatives adapted for one pot reaction involving the use of a pyclizing agent and involving the step of amidation in the presence of a catalyst. The steps for isolation and purification of found Pyrazole derivatives are also disclosed.
US8431609B2
申请人:——
公开号:US8431609B2
公开(公告)日:2013-04-30
[EN] AN IMPROVED PROCESS FOR THE PREPARATION OF RIMONABANT<br/>[FR] PROCÉDÉ AMÉLIORÉ DE PRÉPARATION DU RIMONABANT
申请人:IND SWIFT LAB LTD
公开号:WO2008062480A2
公开(公告)日:2008-05-29
[EN] The present invention relates to an industrially advantageous, eco-friendly process for the re aration of rimonabant of formula-(I), staring from l-(4-chlorophenyl)-propan-l-one in high yields and high purity by using mild reaction conditions and avoiding use of toxic and expensive reagents, as well as stringent reaction conditions. The present invention relates to an isolated impurity of rimonabant, referred to as "Bis impurity" and removal thereof.1 The present invention also relates to novel crystalline form-Ill of rimonabant and processes for its preparation and conversion to form-I of rimonabant. [FR] L'invention porte sur un procédé industriellement avantageux, écologique et à fort rendement, de préparation de rimonabant de formule (I) de grande pureté, à partir de l-(4-chlorophényle)-propane-l-one en utilisant des conditions de réaction douces et en évitant l'utilisation de réactifs toxiques et chers, aussi bien que des conditions de réaction contraignantes. L'invention porte également sur l'isolement et l'élimination d'une impureté du rimonabant, dite "impureté Bis ". L'invention porte en outre sur une nouvelle forme cristalline de formule (III) du rimonabant et sur son procédé de préparation et de conversion pour obtenir le rimonabant de formule (I)