Table 1. 1H (600 MHz), ¹³C (150 MHz), and ¹⁵N (60 MHz) NMR Spectroscopic Data for Isocaulamidine B (1) and Caulamidine B (6) in CD₃OD.

no.	isocaulamidine B (1)		caulamidine B (6)
	${\delta }_{\text{C}}/{\delta }_{\text{N}}$,a type	${\delta }_{\text{H}}$ (mult., J in Hz)	no.	${\delta }_{\text{C}}/{\delta }_{\text{N}}$,a type	${\delta }_{\text{H}}$ (mult., J in Hz)
1N	108.0, N		1N	106.8, N
2	170.0, C		2	168.9, C
3N	-		3N	-
4	148.9, C		4	147.5, C
5	118.4, CH	7.50 (d, 1.7)	5	118.1, CH	7.52 (d, 1.7)
6	125.8, C		6	126.1, C
7	128.6, CH	7.46 (dd, 8.1, 1.7)	7	129.0, CH	7.49 (dd, 8.1, 1.7)
8	127.2, CH	7.34 (d, 8.1)	8	127.4, CH	7.32 (d, 8.1)
9	125.5, C		9	124.5, C
10	58.3, C		10	57.8, C
11	53.8, CH	5.34 (dd, 10.7, 6.3)	11	52.9, CH	5.39 (dd, 10.7, 6.4)
12a	47.7, CH2	4.33 (dd, 15.1, 6.3)	12a	55.0, CH2	4.33 (dd, 14.5, 6.4)
12b		3.81 (dd, 15.1, 10.7)	12b		4.01 (dd, 14.5, 10.7)
13N	-		13N	118.5, N
14	161.8, C		14	161.2, C
15N	122.7, N		15N	130.2, N
16	139.9, C		16	135.9, C
17	121.5, CH	7.63 (d, 1.7)	17	122.2, CH	7.64 (d, 1.9)
18	123.2, C		18	122.9, C
19	130.1, CH	7.41 (dd, 8.0, 1.7)	19	130.6, CH	7.40 (dd, 8.1, 1.9)
20	131.6, CH	7.17 (dd, 8.0, 1.0)	20	131.9, CH	7.16 (dd, 8.1, 1.0)
21	123.6, C		21	121.8, C
22a	29.8, CH2	2.76 (ddd, 16.0, 1.8, 1.0)	22a	30.3, CH2	2.88 (d, 16.5)
22b		2.72 (d, 16.0)	22b		2.81 (ddd, 16.5, 1.8, 1.0)
23	42.3, C		23	41.5, C
24a	25.3, CH2	2.46 (dddd, 15.3, 9.7, 8.1, 1.8)	24a	25.1, CH2	2.60 (dddd, 15.3, 9.2, 7.6, 1.8)
24b		1.97 (ddd, 15.3, 7.2, 2.4)	24b		2.17 (ddd, 15.3, 7.4, 2.7)
25a	48.8, CH2	3.90 (ddd, 13.9, 8.1, 2.4)	25a	48.8, CH2	3.97 (ddd, 13.9, 7.6, 2.7)
25b		3.60 (ddd, 13.9, 9.7, 7.2)	25b		3.69 (ddd, 13.9, 9.2, 7.4)
26	39.8, CH3	3.39 (s)	26	40.2, CH3	3.43 (s)
27	35.9, CH3	3.69 (s)	27	40.1, CH3	3.60 (s)

^aThe ¹⁵N assignments were based on ¹H—¹⁵N HMBC correlations. The ${\delta }_{\text{N}}$ values were not calibrated to an external standard but were referenced to neat NH₃ ($\delta$ 0.00) using the standard Bruker parameters.