Table 1.

¹HNMR spectroscopic data of compounds 1–4

No	1*a	2*b	3*c	4*b
2	6.45, s	6.60, s	6.56, s	6.51, s
4	5.58, br s	6.16, br s	5.89, br s	5.85, br s
5	6.30, br s	6.38, br s	6.70, br s	6.56, br s
7	6.83, d (2.0)	7.02, d (1.8)	7.02, d (2.0)	7.00, d (2.4)
10	4.14, d (3.5)	4.57, d (3.6)	4.55, s	4.39, d (3.0)
3-Me	2.07, s	2.24, s	2.17, s	2.17, s
2′	6.59, s	6.71, s	6.57, s	6.53, s
4′	6.34, br s	6.38, br s	5.98, br s	5.91, br s
5′	5.45, br s	6.15, br s	6.55, br s	6.18, br s
7′	6.18, d (2.5)	6.31, d (1.8)	6.43, d (2.5)	6.18, s
10′	4.08, d (3.5)	4.56, d (3.6)	4.55, s	4.35, d (3.0)
3′-Me	2.29, s	2.31, s	2.22, s	2.17, s
1″	4.60, d (7.5)	4.70, d (7.2)	4.75, d (8.0)	4.76, d (7.2)
2″	3.43, m	3.49, m	3.47, m	3.51,m
3″	3.43, m	3.50, m	3.59, m	3.51, m
4″	3.38, m	3.46, m	3.59, m	3.38, m
5″	3.49, m	3.47, m	3.47, m	3.50, m
6″	3.94, dd (2.5,12) 3.74, dd (5.5,12)	3.96, dd (1.2,11.4) 3.77, dd (5.4,11.4)	3.98, dd (2.5,13) 3.77, dd (5.5,13)	3.94, dd (2.4, 12); 3.71, dd (6.0,12)
6′-0Me	3.74, s	3.84, s	3.95, s	3.88, s
OH-1		12.68, s	12.02, s
OH-8′		11.96, s	12.04, s
OH-1′		11.82, s	11.66, s
OH-6		9.89, s
OH-6′

^{a 1}HNMR data were measured in CD₃OD at 500 MHz

^{b 1}HNMR data were measured in CD₃COCD₃ or CD₃OD at 600 MHz

^{c 1}HNMR data were measured in CD₃COCD₃ at 500 MHz