Table 3.

Selected NMR data for studies on the syn/anti conformation

Nucleoside	H1′	H2′	C1′	C2′	C3′	C4′
2′-OMeG	5.82	4.28	85.85	82.73	68.66	84.32
8-Br-2′-OMeG	5.79	4.78	88.01	79.79	69.27	86.67
8-NO2-2′-OMeG	6.32	4.68	89.12	80.88	69.55	86.02

¹H and ¹³C NMR shifts of sugar protons and carbons of the 2′-O-methyl derivatives of guanosine (2′-OMeG), 8-bromoguanosine (8-Br-2′-OMeG) and 8-nitroguanosine (8-NO₂-2′-OMeG), measured in D6-DMSO. Downfield and upfield chemical shifts for the syn conformation are indicated by turquoise and yellow shading, respectively.