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Several 2-aryl-4-benzyl-5-methyloxazole N-oxides have been synthesized. It has been shown that the action of the POCl3 does not lead to the formation of the product of the known ...deoxygenation-chlorination reaction, but proceeds with the opening of the oxazole ring. As a result, a series of (Z)-N-(3-oxo-1-phenylbut-1-en-2-yl)arylamides was obtained with yields of 25–92%.
One‐pot (CF3CO)2O/K2CO3‐mediated tandem cyclocondensation of β‐ketosulfones with carboxylic acids provides diversified 3‐sulfonylchromones in good to excellent yields by refluxing MeCN under ...high‐pressure (using a sealed tube) and dry‐nitrogen atmospheric conditions. This study proposed and discussed a plausible mechanism. The paper also described the formation of 3‐sulfonylflavones and gram‐scale synthesis of 3‐sulfonylchromones. Various combinations of anhydrides and bases‐promoted reaction conditions were investigated for the (4+2) annulation via one carbon‐oxygen (C−O) bond and one carbon‐carbon (C=C) bond formations.
A new class of benzazolyl azolyl urea derivatives were prepared by the reaction of methyl benzazoyl carbamates with azolyl amines in the presence of mild base potassium tert-butoxide. The presence of ...electron withdrawing substituents on the aromatic ring enhanced the activity. Nitro substituted benzothiazolyl thiazolyl urea, benzothiazolyl imidazolyl urea and benzimidazolyl thiazolyl urea exhibited potential antibacterial activity against Bacillus subtilis. The compound benzothiazolyl imidazolyl urea and nitro substituted benzimidazolyl imidazolyl urea showed potential antifungal activity against Aspergillus niger.
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•Urea derivatives were prepared by the reaction of azolyl carbamates with azolyl amines in the presence of mild base.•Presence of electron withdrawing substituents on the aromatic ring enhanced antimicrobial activity.•14c, 15c and 17c showed greater antibacterial activity on B. subtilis than standard drug Chloramphenicol.•15c and 18c showed excellent antifungal activity on A. niger than standard drug Ketoconazole.
In this article, an improved synthesis of a key triazole intermediate in the synthesis of bromo- and extra-terminal domain (BET) inhibitor GSK525762 (1) is described, which avoids the need for the ...formation of a thioamide intermediate for the key methyltriazolo1,4benzodiazapine formation. Conditions for a phosphorylative activation of lactam 4 were identified through the extensive screening of reagents and solvents, where a number of phosphazene bases were found to have unmatched activity. Development efforts focused on the use of phosphazene base P1-t-Bu-tris(tetramethylene) (BTPP) with diethyl chlorophosphoridate (DECP) and culminated in the demonstration of the new process at a 750 g scale. The resulting synthetic route avoids the use of thiolating agent P2S5 and isolation of the resulting thioamide while delivering 1 in exceptional purity with a reduced number of steps, resulting in a higher yield and improved throughput over the previous process.
The use of negatively charged aluminosilicate layers and Lewis acidic cations embedded therein allowed efficient cyclocondensation of bisamines with water-soluble aldehydes to be achieved in water. ...The protocol does not involve acidic or reflux conditions, thereby avoiding undesired byproduct formation. The use of water as a reaction medium is indispensable to ensure high reaction yields.
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•Under specific Lewis acid activation, cyanoguanidine acts as cyanating agent.•Cyanoguanidine/BF3 allows safe and eco-friendly synthesis of 2-aminobenzoxazoles.•AlCl3 activation ...broadens and optimizes the synthesis of 2-guanidinobenzoxazoles.
An effective, easy-to-handle, safe and inexpensive protocol is reported for the synthesis of 2-aminobenzoxazoles under Lewis acid activation, utilising cyanoguanidine as the cyanating reagent. An optimized procedure for the synthesis of 2-guanidinobenzoxazole and novel derivatives is also described.
This review provides a comprehensive survey relating to the synthesis and biological applications of pyrazolines and related heterocycles in the last five years (2007–2011). These compounds are ...usually prepared from the cyclization of chalcones with hydrazine and its derivatives under the alcoholic conditions. The major incentive behind the synthesis of these compounds was the immense biological activities associated to these heterocyclic derivatives. The aim of this review is to find out different methods for the synthesis of pyrazoline derivatives.
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