Table 1.

¹H and ¹³C NMR (CDCl₃, 500.13 MHz and 125.8 MHz) and HMBC assignment for similanpyrone A (1).

Position	δC, Type	δH, (J in Hz)	COSY	HMBC
2	159.7, C	-
3	114.1, CH	6.36, d (9.8)	H-4	10a
4	137.8, CH	8.13, d (9.8)	H-3	C-2, 4a
4a	107.3, C	-
5	160.3, C	-
5a	101.3, C	-
6	166.3, C	-
8	156.2, C	-
9	104.6, CH	6.33, s	CH3-8	C-5a, 8, 10, Me-8
9a	130.0, C	-
10	102.7, CH	6.70, s		C-4a, 5a, 9a, 10a
10a	140.1, C	-
CH3-8	19.6, CH3	2.33, s	H-9	C-8, 9
OH-5	-	11.90, s		C-4a, 5, 5a