. "No. 224,604 7 Claims. (Cl. 260-471) wherein R is an alkyl group, especially 3 to 8 carbon atoms, preferably secondary or a tertiary lower alkyl group, e.g. t-butyl, secondary octyl R represents hydrogen or at least one alkyl group-e.g., of from 1 to 8 carbon atoms, preferably a secondary or tertiary alkyl adjacent to OH-but in the case of a tertiary alkyl group it is understood that bulky groups a" . . .