Design, synthesis and anti-acetylcholinesterase evaluation of some new pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine derivatives

The target new hybrid molecule types pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c] pyrimidines phosphonates 4 and 2-(coumarin-3 ''-yl)-7-phenylpyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidines 5 were prepared via Michaelis-Arbuzov rearrangement (Arbuzov reaction) of pyrazolotriazolopyrimidines chloride 3a-c, with trialkyl phosphate and Knoevenagel reaction of 2-cyanomethyl derivatives 3d-f with salicylic aldehyde, respectively. The precursors 3 were obtained in two steps starting from aminopyrazole 1. Target compounds 4 and 5 were completely characterized by H-1 NMR, C-13 NMR, P-31 NMR, IR and HRMS. The anti-acetylcholinesterase activity of compounds 4 and 5 was evaluated, and results found indicated that they have possessed significant activities (IC50 = 1.73-39.86 mu M), and the preliminary SAR of these compounds was investigated.