title: Conjugate addition versus cycloaddition/condensation of nitro compounds in water: selectivity, acid-base catalysis, and induction period.
abstract: Nitroacetates and nitroacetamides react in water as in chloroform with electron-deficient dipolarophiles to give condensation or conjugate addition products under base catalysis. In general, high selectivity towards condensation is observed in water, with shorter induction periods than in chloroform. In water, condensations slowly occur even without base; kinetic profiles evidence the catalytic effect of the base, which should be related to the conversion into the tautomer nitronic acid. Condensations in water provide convenient access to isoxazole derivatives bearing various functional groups including ammonium, carboxy, and carboxyamide.
authors.affiliation: Istituto di Chimica dei Composti Organometallici del Consiglio Nazionale delle Ricerche c/o Dipartimento di Chimica Ugo Schiff, Università di Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino, Firenze, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Guideri
authors.forename: Francesco
authors.initials: F
authors.lastname: De Sarlo
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Machetti