150943-49-0 9-(3'-Ethylphosphono-1'-hydroxymethyl-1'-propyloxymethyl)guanine Phosphonic acid, (3-((2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy)-4-hydroxybutyl)-, monoethyl ester, (R)- SR 3727A SR-3727A