Table 1.

¹H-NMR (500 MHz) spectral data of xanthones 1–5.

Position	Compound 1 1	Compound 2 2	Compound 3 2	Compound 4 2	Compound 5 2
1	13.72, s	13.42, s	13.44, s	13.72, s	13.79, s
4	6.28, s	6.24, s	6.30, s	6.26, s	6.37, s
5	6.80, s	6.74, s	6.75, s	6.85, s	−
11	3.35, d (J = 7.3 Hz)	3.37, d (J = 7.2 Hz)	3.36, d (J = 7.1 Hz)	6.74, d (J = 10.0 Hz)	3.48, d (J = 6.0 Hz)
12	5.17, t (J = 7.3 Hz)	5.17, t (J = 7.2 Hz)	5.26, t (J = 7.1 Hz)	5.58, d (J = 10.0 Hz)	5.31, t (J = 7.0 Hz)
14	1.77, s	1.75, s	1.70, s	1.27, s	1.79, s
15	1.63, s	1.62, s	1.71, s	1.28, s	1.71, s
16	4.04, d (J = 7.0 Hz)	4.09, d (J = 7.2 Hz)	4.15, d (J = 7.2, Hz)	4.10, d (J = 7.0 Hz)	3.59, d (J = 6.0 Hz)
17	5.17, t (J = 7.3 Hz)	5.18, t (J = 7.2 Hz)	5.26, t (J = 7.2 Hz)	5.27, t (J = 7.3 Hz)	5.31, t (J = 7.0 Hz)
19	1.71, s	1.61, s	1.70, s	1.71, s	1.87, s
20	1.73, s	1.72, s	1.82, s	1.82, s	1.89, s
3-OMe		3.82, s	3.91, s
6-OMe			3.97, s
7-OMe	3.71, s	3.80, s	3.82, s	3.83, s
1'					8.00, d (J = 10.0 Hz)
2'					5.79, d (J = 10.0 Hz)
4'					1.51, s
5'					1.51, s

¹ DMSO-d₆, ² CDCl₃.