title: Manipulation of N,O-nucleophilicity: efficient formation of 4-N-substituted 2,4-dihydro-3H-1,2,4-triazolin-3-ones.
abstract: A new efficient two-step synthesis of 2,4-dihydro-3H-1,2,4-triazolin-3-ones (triazolinones) from readily available amines is reported. Our novel conditions using hexamethyl disilazane, bromotrimethylsilane, and a catalytic amount of ammonium sulfate smoothly cyclize 1-formyl and 1-acetyl semicarbazides to the target triazolinones. This transformation features simultaneous manipulation of N- and O-nucleophilicity as well as differentiation of the nucleophilicity of a urea and an acyl carbonyl.
authors.affiliation: Department of Medicinal Chemistry, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA. xianhai.huang@spcorp.com
authors.forename: Xianhai
authors.initials: X
authors.lastname: Huang
authors.forename: Anandan
authors.initials: A
authors.lastname: Palani
authors.forename: Dong
authors.initials: D
authors.lastname: Xiao
authors.forename: Robert
authors.initials: R
authors.lastname: Aslanian
authors.forename: Neng-Yang
authors.initials: NY
authors.lastname: Shih