Cyclic phosphates of formycin.

Abstract
The syntheses of N1- and N2-isopropylformycin, formycin 3'',5''-cyclic and 2'',3''-cyclic phosphate and their N-methyl and N-isopropyl derivatives are described. Substitution at N1 or N2 with a bulky alkyl group or cyclic phosphorylation of the ribose moiety made formycin resistant to adenosine deaminase.