Synthesis of N-Vinyl Pyrazoles Using Elmenite (FeTiO۳) as a Magnetic nanoparticles catalyst

Protonation of the highly reactive ۱:۱ intermediates, produced in the reaction of triphenylphosphine and alkyl acetylenecarboxylates, by ۳,۵-Dimethyl-pyrazol leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction to produce the corresponding stabilized phosphoniumylides. Elmenite (FeTiO۳) as a Magnetic nanoparticles catalyst as a New Nanomagnetic Catalyst was found to catalyze the conversion of the stabilized phosphonium ylides to alkyl ۲-(۳,۵-Dimethyl-pyrazol-۱-yl)-acrylic acid methyl ester under solvent-free conditions using microwave (۰.۱۸ KW, ۱ min) and thermal (۷۰ ۰C, ۰.۵ h) conditions. The formulas of these compounds were confirmed by IR, ۱H, and ۱۳C NMR spectroscopy.

کلیدواژه ها:

acetylenic esters ، nanoparticles catalyst ، michael addition ، vinyltriphenylphosphonium salts