The First Reliable, General Synthesis of the 5-Oxo Derivatives of 5,6-Dihydro-1,2,4-triazolo[4,3-c]pyrimidine and the Rates of Isomerization of the [4,3-c] Compounds into Their [1,5-c] Isomers
作者:Tomohisa Nagamatsu、Takayuki Fujita
DOI:10.3987/com-02-9450
日期:——
This paper describes a reliable synthesis of the 5-oxo derivatives (8) of 5,6-dihydro-1,2,4-triazolo[4,3-c]pyrimidine, by the reaction of 2-oxo-1,2-dihydropyrimidin-4-ylhydrazines (7) with the appropriate triethyl orthoesters in trifluoroacetic acid below 30 degreesC or by the oxidative cyclization of their aldehyde hydrazones (10) with 70% nitric acid in trifluoroacetic acid below 40 degreesC, and the rates of isomerization of the [4,3-c] compounds (8) into the [1,5-c] isomers (9).