3′-O-Methylguanosine10300-27-330 % similar 2′-O-Methylguanosine2140-71-830 % similar 2′,3′-Isopropylideneguanosine362-76-530 % similar 2-Aminopurine riboside4546-54-730 % similar 2′-C-Methylguanosine374750-30-830 % similar