Table 1.

¹H and ¹³C NMR data of compounds 1a and 1b (measured in DMSO-d₆).

No.	1a (Major)		1b (Minor)
	δC, Type a	δH (J in Hz) b	δC, Type a	δH (J in Hz) b
1-NH		11.75, s		11.55, s
2	134.6, C		134.4, C
3	138.5, C		138.2, C
5	172.6, C		172.9, C
6	59.6, CH	4.55, dd, (8.5, 4.6)	60.7, CH	5.21, dd, (8.6, 3.5)
7	28.3, CH2	β 1.87, m; α 2.25, m	31.3, CH2	β 1.97, m; α 2.28, m
8	25.2, CH2	1.89, m	21.6, CH2	1.83, m
9	49.6, CH2	β 4.01, m; α 3.89, m	47.8, CH2	3.69, m
11	166.7, C		166.2, C
12	141.9, C		141.8, C
13	113.3, CH	8.33, s	113.4, CH	8.43, s
14	128.1, C		128.3, C
15	114.9, C		114.9, C
16	122.7, CH	8.17, d, (8.7)	122.7, CH	8.17, d, (8.6)
17	109.6, CH	6.88, dd, (8.7, 2.2)	109.6, CH	6.87, dd, (8.6, 2.2)
18	160.4, C		160.4, C
19	94.8, CH	7.04, d, (2.2)	94.8, CH	7.04, d, (2.2)
20	142.3, C		142.5, C
21	119.5, CH	6.79, s	120.0, CH	6.59, s
22	141.1, C		140.4, C
23	20.2, CH3	2.19, s	20.0, CH3	1.91, s
24	27.1, CH3	2.06, s	26.5, CH3	2.03, s
25	55.3, CH3	3.88, s	55.3, CH3	3.87, s
26	51.6, CH3	3.67, s	51.4, CH3	3.46, s

^a Measured at 125 MHz; ^b Measured at 500 MHz.