Reaction between isocyanides and dialkyl acetylenedicarboxylates in the presence of 2,4-dihydro-3H-pyrazol-3-ones. One-pot synthesis of highly functionalized 7-oxo-1H,7H-pyrazolo[1,2-a]pyrazoles
The reactive 1:1 intermediate produced in the reactionbetweenisocyanides and dialkylacetylenedicarboxylates was trapped by 2,4-dihydro-3H-pyrazol-3-ones to yield highlyfunctionalized 7-oxo-1H,7H-pyrazolo[1,2-a]pyrazoles in fairly good yields.