Abstract: Novel compounds of the general formula ##SPC1##Wherein X is H or NH.sub.2 ; R' is C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 substituted alkyl, benzyl, C.sub.1 to C.sub.8 acyl, benzoyl, carbamoyl, are disclosed as well as a novel free radial alkylation and acylation process for making such compounds. The compounds of the invention display activity comparable to or superior to their naturally occurring analogue while resisting phosphodiesterase degradation. In some cases the compounds of this invention actually inhibit enzymatic degradation of the natural analogue.