A rapid and efficient preparation of 2-imidazolines and bis-imidazolines by the reaction of ethylenediamine or 1,2-propanediamine with nitriles in the presence of catalytic amounts of tungstosilicicacidsupported on SiO(2) under reflux condition, is reported. The advantages of this procedure are moderate reaction times, good to high yields and the ability to carry out the large scale reactions.
A practical, efficient, and inexpensive method for the synthesis of 2‐imidazoline from the reaction of nitriles with ethylenediamine or 1,2‐propanediamine using p‐toluenesulfonicacid or pyridinium p‐toluenesulfonate under reflux conditions is reported. This catalyst can be successfully applied for the chemoselective conversion of dicyanobenzenes to corresponding mono‐ and bis‐imidazolines. The applications
Pd-Catalyzed N-arylation of 2-imidazolines Provides Convenient Access to Selective Cyclooxygenase-2 Inhibitors
作者:Mikhail Krasavin
DOI:10.2174/1570178611310040002
日期:2013.5.1
The re-emergence, in the recent years, of cyclooxygenase as a biological target in therapeutic areas other than
inflammation is likely to require new optimized leads, particularly suited for the requirements of specific drug development
programs. We developed a convenient synthesis of the known imidazole-based selective COX-2 inhibitors bearing
primary sulphonamide and methyl sulfone substituents, via Pd-catalyzed imidazoline N-arylation as a key step, followed
by dehydrogenation.
clinically used Celecoxib and was shown to be more selective. The series represents the first example of selectiveCOX-2inhibitors built around a distinctly polar core, contradicting an earlier accepted view that a lipophilic scaffold is required for high inhibitor potency. The lead compound demonstrated very good oral bioavailability in mice, slow metabolic degradation, modest distribution into the
We discovered a facile rearrangement of N-(hetero)aryl 2-imidazolines into diversely substituted imidazo[4,5-b]pyridines and benzimidazoles, under Bechamp reduction conditions. Combined with the earlier reported protocol for Pd-catalyzed (hetero)arylation of 2-imidazolines, it provides a simple two-step access to a range of compounds based on these medicinally important heterocyclic cores. (C) 2013 Elsevier Ltd. All rights reserved.