CH3, --CH2 OH, --CH2 F, and --CH2 NR3 2 wherein each R3 is independently an alkyl of 1 to 5 carbon atoms; and ##STR27## wherein Me is a methyl group, R1, R2, and R3 are each independently --OH, --F, and --NRR wherein each R is independently hydrogen or an alkyl of 1 to 5 carbon atoms. 2.