Synthesis of novel spiroisoxazolidino hybrids of alantolactone and isoalantolactone via 1,3 dipolar nitrone cycloaddition and its antimicrobial Evaluation.

Alantolactone and isoalantolactone are two isomeric sesquiterpene lactones that were isolated from Innula recemosa. Here, we are used for the semisynthesis of novel isoxazolidine hybrids of alantolactone and isoalantolactone through a two-step process: nitrone synthesis followed by nitrone 1,3-dipolar cycloaddition. The formation of the cycloadduct was well characterized via modern spectroscopic techniques such as HRMS, H NMR, C NMR, DEPT-90, DEPT-135, and 2D NMR.