Patent ID: 7115666

Claim:
A compound of formula 1 wherein: (i) n is an integer with a value ranging from two to six; (ii) each R 1 is independently selected from: hydrogen, alkyl, alkenyl, alkynyl. cycloalkyl, cycloalkenyl, aryl, alkaryl, aralkyl, aralkenyl, aralkynyl, halo, haloalkyl, hydroxyl, alkoxyl, hydroxyalkyl, alkoxyalkoxyl, acyl, carboxylate, carboxyl, alkanoyloxy, nitrate, nitrite, nitrile, cyanate, isocyanate, primary amino, secondary amino, tertiary amino, azido, carboxamido, acylamino, thiol, sulfonyl, alkyl sulfonate, aryl sulfonate, sulfonamide, thioaryloxy, thioalkoxy, oxygen heterocycles, nitogen heterocycles and sulfur heterocycles; (iii) R 2 , R 3 and R 5 are each independently selected from hydrogen, alkyl and cycloalkyl; and (iv) R 4 is selected from alkyl, cycloalkyl, cycloalkylalkylene, cycloalkenyl, aryl and aralkyl, provided that: not all R 1 s are hydrogen.