139438-58-7Relevant articles and documents
Tricyclic Heteroaromatic Systems Containing a Bridgehead Nitrogen Atom. Part 3. Triazolopyrazolopyrimidines, Tetrazolopyrazolopyrimidines and Pyrimidopyrazolotriazines
Golec, Julian M. C.,Scrowston, Richard M.,Dunleavy, Michael
, p. 239 - 244 (2007/10/02)
6-Phenyl-1H-pyrazolopyrimidin-3(2H)-one 16 has been prepared and converted into its 3-chloro 6, 3-thioxo 17 and 3-methylthio derivatives 9.Each of these could be converted into the 3-hydrazino derivative 3, cyclisation of which with carbon disulfide or triethyl orthoformate generated the fused 1,2,4-triazoles 23 and 20, respectively.Alternatively, the hydrazino derivative 3 gave a substituted hydrazide 26 or thiosemicarbazide 25, from which the 1,2,4-triazoles 21 and 22 respectively were obtained.The equilibrium between 3-azido-6-phenyl-1H-pyrazolopyrimidine 5 and 2-phenyl-9H-tetrazolopyrazolopyrimidine 27 was studied. 3-Diazo-4-methyl-6-phenyl-1H-pyrazolopyrimidine 29 was prepared by diazotisation of the corresponding amine 1 and converted into the 3-azido compound 4, which could not be cyclised to form a tetrazole.Finally, the diazo compound 29 readily formed the pyrimidopyrazolotriazine derivatives 32 and 33, when treated with pentane-2,4-dione and ethyl acetoacetate respectively.
