(2S,2'S)-2-((2-amino-6-oxo-1H-purin-9(6H)-yl)methoxy)propane-1,3-diyl bis(2-(((benzyloxy)carbonyl)amino)-3-methylbutanoate); ((2-Amino-6-oxo-1H-purin-9(6H)-yl)methoxy)propane-1,3-diyl bis(2-(((benzyloxy)carbonyl)amino)-3-methylbutanoate), (2S,2'S)-2-;