Reaction of tetrahalo-benzoquinones with 3- [2furyl] -1 [2-thienyl] -2-propen1-one and 1-aryl-5- [2-furyl] -3- [2-thienyl] -pyrazolines

It has been reported [1, 2] in our laboratory that the furan ring undergoes cycloaddition reaction with halo-o-benzoquinones. The quinones added readily, under very mild conditions, to the 4,5-double bond of the furyl residue of 2-vinylfurans to give adducts of the type [2] with retention of the vinyl side chain