An efficient synthesis of 1-cyanoacetyl-5-halomethyl-4,5-dihydro- 1H-pyrazoles in ionic liquid

摘要

The synthesis of eleven 1-cyanoacetyl-5-hydroxy-5-halomethyl-4,5-dihydro-1H-pyrazoles from the reaction of 4-alkoxy-3-alken-2-ones (R~3C(O)C(R~2) = C(R~1)OR, where R~3 = CF3, CCl3, CHCl2, Co2Et; R~2/R~1 = H/H, H/Me, K/Et, -(CH2)4-, Me/H, R/Pr, and R = Me, Et) with cyanoacetohy-drazide is reported. The reaction was carried out in the ionic liquid ([bmim] [BF4]) and molecular solvents. The results showed that when the ionic liquid was used as reaction medium, the reaction time was drastically decreased and the yield was improved.