Table 1.

¹H and ¹³C-NMR data for 8,8′-oxo-biplumbagin (1).

Position	δH (I, m, J in Hz)	δC	HMBC (2J, 3J)
1,1′	-	185.2	-
2,2′	-	150.0	-
3,3′	6.80, (2H, q, 1.6)	134.9	C1, C1′, C10, C10′, C11, C11′
4,4′	-	190.5	-
5,5′	-	161.3	-
6,6′	7.29, (2H, d, 8.6)	124.3	C10, C10′, C5, C5′, C7, C7′, C8, C8′
7,7′	7.20 (2H, d, 8.6)	137.9	C5, C5′, C6, C6′, C8, C8′, C9,C9′
8,8′	-	135.6	-
9, 9′	-	128.2	-
10, 10′	-	115.5	-
11,11′	2.01 (6H, d, 1.6)		C1, C1′, C2, C2′, C3, C3′
5-OH, 5′-OH	12.58 (2H, brs)	-	C10, C10′, C5, C5′, C6, C6′