Table 2.

¹³C NMR spectroscopic data of 1–5 (δ in ppm)

No.	1 a	2 b	3 b	4 c	5 c
1	157.8 s	173.6 s	165.8 s	165.6 s	165.3 s
2	122.0 d	31.6 t	118.3 d	118.1 d	119.1 d
3	133.5 d	19.8 t	143.1 d	142.3 d	141.3 d
4	126.6 s	111.6 s	121.9 s	120.7 s	123.7 s
5	157.7 s	131.3 s	144.1 s	145.9 s	145.9 s
6	35.0 t	28.0 t	30.0 t	35.2 t	72.1 d
7	33.1 d	41.6 d	35.3 d	34.3 d	42.2 d
8	42.7 t	78.8 d	126.3 d	125.8 d	121.3 d
9	40.4 t	43.3 t	51.8 t
10	23.3 t	27.3 t	21.1 t	12.5 q	12.5 q
11	24.3 t	26.7 t	26.9 t	114.3 d	115.0 d
12	41.6 d	38.1 d	34.3 d	137.3 s	140.3 s
13	61.2 s	58.2 s	58.3 s	61.1 s	55.7 s
14	47.4 t	42.4 t	39.9 t	50.7 t	50.2 t
15	26.0 d	147.4 s	137.8 s	135.4 s	136.6 s
16	21.5 q	115.1 t	66.4 t	22.7 q	22.9 q
17	24.2 q
N-CH3			38.0 q	29.7 q

^aRecorded at 125 MHz in C₅D₅N

^bRecorded at 125 MHz in CD₃OD

^cRecorded at 150 MHz in CD₃OD