"yl, benzyl, phenylethyl, p- methoxybenzyl, 9-fluorenylmethyl, and the like, CH 2 =CH-CH 2 -, and the like; amides - groups of the formula -C(O)-R' wherein R' is for example methyl, phenyl, thfluoromethyl, and the like; N-sulfonyl derivatives - groups of the formula -SO 2 -R wherein R is for example tolyl, phenyl, thfluoromethyl, 2,2,5,7,8-pentamethylchroman-6-yl-, 2,3,6-trimethyl-4-methoxybenzen" . . . .