. . "tramolecularly covalently bonded to each other and to the same dioxycarbon atom to form a heterocyclic ring or a heterocyclic ring substituted with an alkyl, alkoxy or alkenyl when R2 is an alkyleneoxy or alkenyleneoxy and R3 is an alkyleneoxy, alkenyleneoxy or alkylene; c) R1 is divalent when R2 and R3 are intramolecularly covalently bonded to each other and to the same dioxy carbon atom to form" . .