Preparation of Isoxazolines by Thermolysis of Ethyl 2-Nitroalkanoates in the Presence of Dipolarophiles

Abstract

3-Alkyl-2-isoxazolines and 3-alkylisoxazole were prepared by thermolysis of ethyl 2-nitroalkanoates at about 230 °C in the presence of dipolarophiles.

Click chemistry methodology in the synthesis of anabasine and cytisine conjugates with isoxazole derivatives

“…The second step in the synthesis of the target conjugates implied 1,3-dipolar cycloaddition to build up isoxazole ring. Various procedures for 1,3-dipolar cycloaddition of nitrile oxides to acetylenes have been reported [24][25][26]. However, the conventional method, i.e., 1,3-dipolar cycloaddition of N-(prop-2-yn-1-yl)cytisine (2) as dipolarophile to nitrile oxides generated in situ from N-hydroxyarenecarboximidoyl chlorides [27], was inefficient, and the reaction mixtures contained no desired cytisine-isoxazole conjugates.…”