Manipulation of N,O-nucleophilicity: efficient formation of 4-N-substituted 2,4-dihydro-3H-1,2,4-triazolin-3-ones.
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.
Huang
Xianhai
X
Department of Medicinal Chemistry, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA. xianhai.huang@spcorp.com
Palani
Anandan
A
Xiao
Dong
D
Aslanian
Robert
R
Shih
Neng-Yang
NY