Table 2. NMR Chemical Shifts and Coupling Constants for Strictosidinic Acid Isomers Isolated from C. acuminata Leaf Tissue as Measured from J-Resolved 1H Spectra and 1H-13C cHSQC Spectra
Carbon number and group1H shift (ppm) and 3JH-H coupling constants (Hz)13C shift (ppm) and 1JC-H coupling constants (Hz)1H shift (ppm) and 3JH-H coupling constants (Hz)13C shift (ppm) and 1JC-H coupling constants (Hz)
Isomer 2Isomer 3
3 (CH)4.45 (dd), 3J = 3.4, 7.7 Hz50.8, 1J = 144 Hz4.56 (dd), 3J = 3.6, 7.9 Hz53.1, 1J = 143 Hz
5 (CH2)3.29 (m)41.3, 1J = 143, 145 Hz;3.45 (m)39.6, 1J = 139, 141 Hz
3.75 (m)3.50 (m)
6 (CH2)3.01 (m)18.1, 1J = 131, 133 Hz2.99 (m)18.2, 1J = 129, 131 Hz
3.29 (m)3.04 (m)
9 (CH)7.56 (d), 3J = 7.9 Hz117.7, 1J = 159 Hz7.55 (d), 3J = 7.9 Hz117.6, 1J = 158 Hz
10 (CH)7.15, 3J = 7.4 Hz119.1, 1J = 159 Hz7.13, 3J = 7.3 Hz118.9, 1J = 158 Hz
11 (CH)7.23, 3J = 7.6 Hz121.9, 1J = 159 Hz7.23, 3J = 7.6 Hz121.8, 1J = 158 Hz
12 (CH)7.42, 3J = 8.2 Hz110.7, 1J = 159 Hz7.45, 3J = 8.2 Hz110.8, 1J = 158 Hz
14 (CH2)2.15 (dd), 3J = 4.6, 11.1 Hz;33.7, 1J = 128, 129 Hz1.98 (m)34.1, 1J = 130, 131 Hz
2.40 (dd), 3J = 5.9, 11.6 Hz2.46 (m)
15 (CH)3.00 (m)32.6, 1J = 137 Hz2.96 (m)32.9, 1J = 135 Hz
17 (CH)7.67 (s)151.7, 1J = 191 Hz7.35 (s)148.4, 1J = 192 Hz
18 (CH2)5.32 (d), 3J = 10.7 Hz;117.5, 1J = 155, 158 Hz5.39 (d), 3J = 11.0 Hz;118.4, 1J = 154, 161 Hz
5.43 (d), 3J = 17.3 Hz5.47 (d), 3J = 17.3 Hz
19 (CH)5.96 (dd), 3J = 10.3, 17.5 Hz134.8, 1J = 156 Hz6.19 (dd), 3J = 10.2, 17.2 Hz134.8, 1J = 152 Hz
20 (CH)2.70 (m)44.2, 1J = 134 Hz2.74 (m)44.9, 1J = 132 Hz
21 (CH)5.93 (d), 3J = 9.5 Hz95.1, 1J = 170 Hz5.64 (d), 3J = 8.2 Hz95.5, 1J = 178 Hz
1′ (CH)4.92 (d), 3J = 8.0 Hz98.9, 1J = 163 Hz4.85 (d), 3J = 7.9 Hz98.8, 1J = 162 Hz
2′ (CH)3.44 (m)76.5, 1J = 145 Hz3.41 (m)76.5, 1J = 145 Hz
3′ (CH)3.41 (m)77.3, 1J = 145 Hz3.35 (m)77.3, 1J = 145 Hz
4′ (CH)3.26 (m)70.2, 1J = 145 Hz3.28 (m)70.3, 1J = 145 Hz
5′ (CH)3.24 (m)73.3, 1J = 145 Hz3.24 (m)73.3, 1J = 145 Hz
6′ (CH2)3.68 (dd), 3J = 4.95, 12.2 Hz;61.6, 1J = 141, 142 Hz3.76 (dd), 3J = 6.61, 12.3 Hz;61.5, 1J = 131, 132 Hz
4.12 (dd), 3J = 2.17, 12.1 Hz4.05 (dd), 3J = 2.40, 12.6 Hz
  • Notable differences in 1H chemical shifts and 1JC-H coupling constants were observed for position 21 (highlighted in bold in the table).