0000000000114798
AUTHOR
Mercedes Medio Simón
Evidence of a 1,4-dipole intermediate in the reaction of 1-phenyl-4-vinylpyrazole with ptad
Abstract 1-Phenyl-4-vinylpyrazole reacts with 1-phenyl-1,2,4-triazoline-3,5-dione in methylene chloride to form an unstable azetidine (4). An intermediate 1,4-dipole is probably involved since, when the reaction is conducted in acetone, a 1:1:1 adduct (3) is isolated.
New cycloaddition reactions of 1-phenyl-4-vinylpyrazole
Abstract 1-Phenyl-4-vinylpyrazole reacts with methyl propiolate and N-phenylmaleimide giving via the Diels-Alder 1:1 adducts, products (4) and (8), and also the 1:2 adducts (5), (6) and (9) resulting from an “ene” reaction of the initially forced cycloadducts. The obtention of the adducts (5) and (6) in equimolecular amounts is a good example of the non-regioselective character of the “ene” reaction. The reaction with tetracyanoethylene takes place through the olefinic substituent giving the π2 + π2 adduct (10).