title: One-pot sequential synthesis of isocyanates and urea derivatives via a microwave-assisted Staudinger-aza-Wittig reaction.
abstract: A fast and efficient protocol for the synthesis of N,N'-disubstituted urea derivatives from alkyl halides and primary or secondary amines has been developed. The synthetic pathway combines nucleophilic substitutions and a Staudinger-aza-Wittig reaction in the presence of polymer-bound diphenylphosphine under 14 bar of CO2 pressure and has been performed in a one-pot two-step process. The protocol has been optimized under microwave irradiation and the scale-up experiment has been conducted under conventional conditions in a Parr reactor. The final compounds were isolated after simple filtration in almost quantitative overall yields which makes this procedure facile and rapid to execute.
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via Pietro Giuria 9, 10125 Torino, Italy; Fax +390116707687; Tel: +390116707684.
authors.forename: Diego
authors.initials: D
authors.lastname: Carnaroglio
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via Pietro Giuria 9, 10125 Torino, Italy; Fax +390116707687; Tel: +390116707684.
authors.forename: Katia
authors.initials: K
authors.lastname: Martina
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Via Valleggio 11, 22100 Como, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Palmisano
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Via Valleggio 11, 22100 Como, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Penoni
authors.affiliation: Department of Chemistry, Universidad Nacional del Sur, Av. Alem 1253, B8000CPB, Bahía Blanca, Buenos Aires, Argentina.
authors.forename: Claudia
authors.initials: C
authors.lastname: Domini
authors.affiliation: Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via Pietro Giuria 9, 10125 Torino, Italy; Fax +390116707687; Tel: +390116707684.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Cravotto
keywords: isocyanates; microwave-assisted reaction; one-pot reaction; tandem Staudinger–aza-Wittig reaction; urea derivatives