Table 3.

NMR spectroscopic data for compound 3^a. ^aSpectra measured at 500 MHz in CDCl₃.

No.	1H	13C	COSY	Key HMBC
1	2.47, m	26.4, CH	H-2, H-19	C-3, C-9
2	1.80, m	30.4, CH2	H-1, H-3	C-1, C-4, C-9
	0.71, m
3	1.43, m	25.8, CH2	H-2, H-4	C-2, C-10
	0.94, m
4	1.24, m	43.3, CH	H-3, H-10, H-11	C-9, C-11
5	1.95, m	35.4, CH	H-10	C-4, C-20
6	—	178.2, C	—	—
7	5.37, brs	123.7, CH	—	C-5, C-20
8	—	209.1, C	—	—
9	—	43.0, C	—	—
10	1.34, m	54.4, CH	H-4, H-5	C-3, C-6
11	2.45, m	38.0, CH	H-4, H-12, H-13	C-3, C-14
12	0.87, d (7.0)	16.6, CH3	H-11	C-4, C-13
13	5.54, d (16.0)	135.0, CH	H-11, H-14	C-12, C-15
14	5.62, dd (16.0, 6.0)	130.7, CH	H-13, H-15	C-11, C-16
15	5.01, d (6.0)	114.4, CH	H-14	C-16, C-17, C-18
16	—	123.6, C	—	—
17	1.34, s	24.5, CH3	—	C-15
18	1.32, s	24.2, CH3	—	C-15
19	0.93, d (6.0)	19.8, CH3	H-1	C-1, C-9
20	2.15, s	18.9, CH3	H-6	C-5, C-6, C-7