Table 1.

NMR Data (400 MHz, MeOH-d₄) of Compounds 1 and 2.

	1			2
position	δH, mult. (J in Hz)	δC, type	HMBCa	δH, mult. (J in Hz)	δC, type	HMBCa
2		167.0, C			161.8, C
3	6.28, s	112.0, CH	2, 4, 4a, 5, 1′	6.21, s	107.3, CH	2, 4, 4a, 5, 1′
4		179.4, C			177.6, Cc
4a		114.9, C			112.9, C
5		136.8, C			138.5, Cc
6	7.20, d (2.3)	103.3, CH	4a, 8, 5-COOH	7.13, d (2.3)	100.8, CH	4a, 8, 5-COOH
7		165.4, C			163.4, C
8	7.22, d (2.3)	116.8, CH	4a, 6, 7, 8a	7.20, d (2.3)	114.0, CH	4a, 7, 8a
8a		160.6, C			157.9, C
1′a	2.88, dd (4.1, 14.7)	043.3, CH2	2, 3, 2′, 3′	6.33, dd (1.4, 15.6)	121.5, CH	2, 3′
1′b	2.70, dd (9.2, 14.7)	2, 3, 2′, 3′
2′	4.06, m	070.0, CH		6.98, dt (7.3, 15.6)	141.8, CH	2, 3′, 4′
3′	1.56, mb	040.8, CH2	1′, 2′, 4′, 5′	2.31, ddt (1.4, 7.3, 7.3)	034.0, CH2	1′, 2′, 4′, 5′
4′	1.56, mb / 1.45, m	020.1, CH2	2′, 3′, 5′	1.58, sextet (7.3)	020.9, CH2	2′, 3′, 5′
5′	0.98, t (6.9)	014.5, CH3	3′, 4′	1.00, t (7.3)	012.1, CH3	3′, 4′
7-OCH3	3.96, s	057.1, CH3	7	3.95, s	054.9, CH3	7
5-COOH		171.9, C			171.5, Cc

^aHMBC correlations are from the proton(s) listed to the indicated carbons.

^bOverlapping signals

^cThe quaternary ¹³C signals for C-4, C-5, and 5-COOH were very weak, and their δ_C values were corroborated by HMBC data.