α-Haloacrylates as acceptors in the [3 + 2] cycloaddition reaction with NaN₃: an expedient approach to N-unsubstituted 1,2,3-triazole-4-carboxylates

An expedient synthesis of N-unsubstituted 1,2,3-triazole-4-carboxylates has been demonstrated through [3 + 2] cycloaddition of sodium azide with α-haloacrylates. The process is highly reliable and exhibits an unusually wide scope with respect to α-fluoro-, α-chloro-, α-bromo-, and α-iodoacrylates. The potential of selected 1,2,3-triazole-4-carboxylates in the preparation of 1,5-dihydro-4H-[1,2,3]-triazolo-[4,5-c]-quinolin-4-one has also been illustrated.