¹H NMR (600 MHz) and ¹³C NMR (150 MHz) data for compounds 6a/6b in CD₃OD.

Position	6a		6b
	δ C, mult.	δ H, mult. (J in Hz)	δ C, mult.	δ H, mult. (J in Hz)
1	183.3, C		182.6, C
2	45.7, C		44.7, C
3	81.4, CH	3.93, brs	83.5, CH	3.95, brs
4	87.7, C		86.0, C
5	138.2, CH	5.89, d (14.5)	134.7, CH	6.01, dd (14.8, 2.6)
6	129.1, CH	6.27, m	129.7, CH	6.27, m
7	130.7, CH	6.27, m	131.1, CH	6.27, m
8	137.2, CH	5.80, dd (14.6, 6.4)	136.7, CH	5.77, dd (14.5, 6.4)
9	71.0, CH	4.43, q (6.4)	71.1, CH	4.43, q (6.4)
10	34.3, CH2	2.94, dd (15.6, 6.2)	34.3, CH2	2.94, dd (15.6, 6.2)
		2.91, dd (15.6, 7.2)		2.91, dd (15.6, 7.2)
11	151.7, C		151.7, C
12	124.0, CH	6.90, s	124.0, CH	6.90, s
13	152.6, CH	8.09, s	152.6, CH	8.08, s
14	20.4, CH3	1.19, s	19.7, CH3	1.04, s
15	26.2, CH3	1.22, s	25.3, CH3	1.21, s
16	22.0, CH3	1.43, s	27.4, CH3	1.49, s