Table 2.

¹³C-NMR (150 MHz), ¹H-NMR (600 MHz) and HMBC spectral data of 8,9,11,12-tetrahydromecambrine (3) in CDCl₃ (δ in ppm, J in Hz).

Position	13C (δ, CDCl3)	Type	1H (J, Hz)	HMBC (2J, 3J)
1	140.7	Cq	-	-
1a	134.3	Cq	-	-
1b	124.5	Cq	-	-
2	148.2	Cq	-	-
3	106.5	CH	6.49 s	C1a, C1, C2,C4
3a	126.9	Cq	-
4	27.4	CH2	2.92 (m) ax	C1b, C5
			2.72 (m) eq	C1b, C1a, C3
5	55.0	CH2	3.09 (m) ax	C1b, C4, NCH3, C6a
			2.45 (m) eq
6a	65.7	CH	3.30 br s	-
7	44.5	CH2	2.59 (m) ax	C3a, C1a, C8, C7a, C6a
			1.75 (m) eq	C8, C12, C7a, C6a
7a	46.0	Cq	-	-
8	34.6	CH2	2.14 (m) ax	C3a, C12, C7
			2.02 (m) eq	C3a, C12, C7a
9	39.0	CH2	2.47 (m)	C8, C11, C7a
				C8, C11, C7a
10	211.7	C=O	-	-
11	38.6	CH2	2.70 (m) ax	C12, C7a
			2.43 (m) eq	C12, C7a
12	36.5	CH2	2.50 (m) ax	C8, C11, C7
			1.93 (m) eq	C3a, C8, C11, C7a
N-CH3	43.5	CH3	2.39 s	C5, C6a
Methlenedioxy	100.6	CH2	5.88 d (J = 1.2)	C1, C2
(O-CH2-O)			5.83 d (J = 1.2)	C1, C2