Abstract: Compounds of the formula: ##STR1## in which R.sup.1 is alkyl; R.sup.2 and R.sup.3 are alkyl or taken together they are polymethylene, R.sup.2 and R.sup.3 complete a 5-norbornen-2-yl moiety; X is --CO.sub.2 --, --OCO--, --OCO.sub.2 --, --N(R.sup.7)CO--, --NHNHCO--, --ON(R.sup.7)CO--, --CON(R.sup.7)--, --N(R.sup.7)CO.sub.2 --, --OCON(R.sup.7)-- or --N(R.sup.7)CON(R.sup.8)--, wherein R.sup.7 and R.sup.8 are, independently, hydrogen, alkyl, phenyl, benzyl, substituted phenyl or substituted benzyl in which the substituents are halo, alkyl alkoxy, cyano, nitro or perhalomethyl; R.sup.4 is hydrogen or alkyl; R.sup.5 is hydrogen, alkyl, hydroxyalkyl, phenyl, benzyl, substituted phenyl or substituted benzyl in which the substituents are hydroxy, halo, alkyl alkoxy, trifluoromethyl, nitro, cyano, carbalkoxy, carboxamido, amino, alkylamino or dialkylamino; R.sup.