(3aS,4S,6R,6aR)-6-[6-(2-Amino-ethylamino)-purin-9-yl]-2,2-dimethyl-tetrahydro-furo[3,4-d][1,3]dioxole-4-carboxylic acid ethylamide

{2-[9-((3aR,4R,6S,6aS)-6-Ethylcarbamoyl-2,2-dimethyl-tetrahydro-furo[3,4-d][1,3]dioxol-4-yl)-9H-purin-6-ylamino]-ethyl}-carbamic acid tert-butyl ester