The novel compounds of the invention are subject to thefollowing provisos: in formula II when R.sup.1 is H, A is a residue of an active hydrogen reactive compound which is an unsaturated isocyanate, an unsaturated anhydride, or an active hydrogen reactive compound which does not contain ethylenicunsaturation; in formula III when R.sup.1 is H, A and B are not both H.DETAILED DESCRIPTION OF THE INVE