title: 5,5-Dimethyl-1,4,2-dioxazoles as versatile aprotic hydroxamic acid protecting groups.
abstract: 5,5-Dimethyl-1,4,2-dioxazoles are readily installed by transketalization of 2,2-diethoxypropane, where both the NH and OH moieties are protected in a nonprotic form. The dioxazoles are stable to a wide variety of reaction conditions and readily revert back to the hydroxamic acid by treatment with Nafion-H in 2-propanol. The method is applicable to primary, secondary, tertiary, and aromatic hydroxamic acids, and the acidity of the protons adjacent to the dioxazole allows alpha-functionalization.
authors.affiliation: Process Research and Development, Pfizer Global Research and Development, Eastern Point Road, P.O. Box 8013, Groton, Connecticut 06340-8013, USA. michael_a_couturier@groton.pfizer.com
authors.forename: Michel
authors.initials: M
authors.lastname: Couturier
authors.forename: John L
authors.initials: JL
authors.lastname: Tucker
authors.forename: Caroline
authors.initials: C
authors.lastname: Proulx
authors.forename: Ghislain
authors.initials: G
authors.lastname: Boucher
authors.forename: Pascal
authors.initials: P
authors.lastname: Dubé
authors.forename: Brian M
authors.initials: BM
authors.lastname: Andresen
authors.forename: Arun
authors.initials: A
authors.lastname: Ghosh