Table 2.

¹H and ¹³C NMR Chemical Shifts of Microcystin 2 Measured in CD₃OH (600 MHz, 25 °C)(A Part of the HMBC spectrum was additionally recorded at 800 MHz).

MC2
Unit	C/H no	δ C	δH (J in Hz)	HMBC a	ROESY
Adda	1	176.9
	2	45.2	2.91, m		11
	3	55.8	4.60, m	2, 4, 5
	4	126.2	5.46, dd (15.4, 8.5)	6	3, 11, 12
	5	138.3	6.24, d (15.4)	3, 6, 7, 12	3, 4, 7, 11, 12
	6	133.6
	7	136.9	5.43, d (9.8)	5, 12	8, 13
	8	37.4	2.58, m		12, 13
	9	88.1	3.23, m
	10a	38.7	2.79, dd (14.0, 4.9)	9, 15, 16/20	13
	10b		2.65, dd (14.0, 7.4)	8, 9, 15, 16/20
	11	15.9	1.05, d (6.8)	1, 2, 3
	12	12.5	1.61, s	5, 6, 7
	13	16.1	0.99, d (6.7)	7, 8, 9
	14	58.4	3.22, s	9
	15	140.3
	16/20	130.5	7.17, m	18, 10	10a/b
	17/19	128.9	7.23, m	15, 17/19
	18	126.7	7.16, m	16/20
	NH		7.68, d (8.6)		2, 3, 4, Hty2-2
Glu	1	175.9
	2	54.1	4.32, m	1, 3	3b, 4b
	3a	28.3	2.07, m
	3b		1.97, m
	4a	33.8	2.43, m
	4b		2.29, m
	5 NH	174.6	n.d.
Dhb	1	166.5
	2	131.5
	3	124.3	5.74, q (7.4)	1, 2	4
	4	13.2	1.93, d (7.4)	2, 3
	NH		9.84, s	1, Glu-5	3, Glu-4a/b
Ala	1	175.4
	2	49.4	4.60, m	1, 3, Dhb-1	3
	3	17.0	1.34, d (7.2)	1, 2
	NH		8.04, d (7.9)		2, 3, Hty2-6/10
Hty1	1	174.2
	2	55.9	4.16, m	1	3a/b, 4b
	3a	34.0	2.25, m
	3b		2.10, m
	4a	32.1	2.74, m	6/10	4b
	4b		2.54, m	6/10
	5	132.9
	6/10	130.6	7.02, d (8.5)	4, 6/10, 8	2, 3a/b, 4a/b
	7/9	116.0	6.65, d (8.5)	5, 7/9, 8
	8	156.3
	NH		8.74, d (7.1)	1, Ala-1	2, 3a/b, 4a/b, Ala-2, Ala-NH, Asp-NH
Asp	1	n.d.
	2	51.1	4.77, m
	3a	37.1	2.94, m		3b
	3b		2.31, m
	4	175.0
	NH		8.17, d (9.1)		3b
Hty2	1	172.7
	2	53.2	4.36, m	1, Asp-4	3a/b, 4b
	3a	34.0	2.26, m		3b
	3b		1.74, m
	4a	32.0	2.54, m	5	3a/b
	4b		2.45, m	5, 6/10	3a/b
	5 6/10	132.8 130.1	6.94, d (8.5)	6/10, 8	2, 3a/b, 4a, Ala-3
	7/9	116.0	6.64, d (8.5)	5, 7/9, 8
	8	156.5
	NH		8.64, d (8.8)	Asp-4

^aHMBC correlations are given from proton(s) stated to the indicated carbon atom.