LAUSR

Abstract In the present work, we have efficiently synthesized the pyrrole-isoxazoline derivatives ( 4a-d ) by cyclization of substituted 4-chalconylpyrrole ( 3a-d ) with hydroxylamine hydrochloride. The reactivity of substituted 4-chalconylpyrrole ( 3a-d ), towards nucleophiles hydroxylamine hydrochloride was evaluated on the basis of electrophilic reactivity descriptors ( f k + , s k + , ω k + ) and they were found to be high at unsaturated β carbon of chalconylpyrrole indicating its more proneness to nucleophilic attack and thereby favoring the formation of reported new pyrrole-isoxazoline compounds ( 4a-d ). The structures of newly synthesized pyrrole-isoxazoline derivatives were derived from IR, 1 H NMR, Mass, UV–Vis and elemental analysis. All experimental spectral data corroborate well with the calculated spectral data. The FT-IR analysis shows red shifts in v N–H and v C = O stretching due to dimer formation through intermolecular hydrogen bonding. On basis set superposition error correction, the intermolecular interaction energy for ( 4a-d ) is found to be 10.10, 9.99, 10.18, 11.01 and 11.19 kcal/mol respectively. The calculated first hyperpolarizability ( β 0 ) values of ( 4a-d ) molecules are in the range of 7.40–9.05 × 10 −30  esu indicating their suitability for non–linear optical (NLO) applications. Experimental spectral results, theoretical data, analysis of chalcone intermediates and pyrrole–isoxazolines find usefulness in advancement of pyrrole-azole chemistry.