. 2020 Jan 22;83(2):447–452. doi: 10.1021/acs.jnatprod.9b01017

Table 1. ¹H and ¹³C NMR Data of Rabenchromenone (1)^a^,^b.

number	δ_C^c	δ_H (J in Hz)	HMBC
1	79.6 s		H-2
2	139.2 d	6.65 s
3	127.1 s		H-2
3a	164.7 s		H-2
4a	156.3 s		H-7
5	108.2 d	6.70 br s	H₃-10
6	147.1 s		H₃-10
7	113.7 d	6.89 br s	H₃-10
8	161.0 s
8a	109.3 s		H-7
9	176.4 s
9a	119.3 s		H-2
10	22.2 q	2.43 s	H-5, H-7
1′	170.5 s		H₃-2′
2′	54.1 q	3.79 s
OH		12.11 s

The chemical shifts are in δ values (ppm) from tetramethylsilane (TMS).

Two-dimensional (2D) ¹H, ¹H (COSY) and ¹³C, ¹H (HSQC) NMR experiments delineated the correlations of all of the protons and the corresponding carbons.

Multiplicities were assigned by the distortionless enhancement by polarization transfer (DEPT) spectrum.

Table 1. 1H and 13C NMR Data of Rabenchromenone (1)a,b.

Table 1. ¹H and ¹³C NMR Data of Rabenchromenone (1)^a^,^b.