figure 3 1H NMR spectrum of 5-hydroxy-7-methoxy-4-methylphthalide (400 MHz, DMSO).
The 1H NMR spectrum of 5-hydroxy-7-methoxy-4-methylphthalide (Figure 3) showed signals for methyl group at δ 1.95 (H-9, singlet, 3H), a signal for the methoxyl group at δ 3.79 (H-8, singlet, 3H), a signal corresponding to one methylene group at δ 5.15 (H-3, singlet, 2H), and a signal for aromatic hydrogen at δ 6.49 (H-6, singlet, 1H).
Figure 1 Structures of the compounds mycophenolic acid and 5-hydroxy-7-methoxy-4-methylphthalide.
TABLE I 1H, 13C and gHMBC NMR data for the compounds mycophenolic acid and 5-hydroxy-7methoxy-4methylphthalide
Position | | Mycophenolic acid | 5-hydroxy-7methoxy-4methylphthalide |
δ 13C | δ 1H(multiplicity, J in Hz) | 1H-13C gHMBC* | δ 13C | δ 1H(multiplicity, J in Hz) | 1H-13C gHMBC * |
1 | 173.0 | - | | 173.0 | - | - |
3 | 70.0 | 5.18 (2H, br s) | 1; 3a | 68.0 | 5.15 (2H, br s) | 1; 3a; 4; 5; 7; 7a |
3a | 122.1 | - | - | 104.0 | - | - |
4 | 116.7 | - | - | 110.0 | - | - |
5 | 163.7 | - | - | 163.0 | - | - |
6 | 106.4 | - | - | 98.0 | 6.49 (1H, s) | 1; 4; 5; 7; 7a |
7 | 153.7 | - | - | 158.0 | - | - |
7a | 144.0 | - | - | 151.0 | - | - |
8 | 61.0 | 3.74 (3H, s) | 5 | 57.0 | 3.79 (3H, s) | 7 |
9 | 11.5 | 2.13 (3H, s) | 3; 3a; 4; 5 | 11.0 | 1.95 (3H, s) | 3a; 4; 5 |
OH | - | 7.67 (1H, br s) | - | - | 10.59 (1H, br s) | 4; 6; 5 |
1’ | 179.1 | - | - | - | - | - |
2’ | 32.7 | 2.38-2.47 (2H,m) | 1’; 3’; 4’ | - | - | - |
3’ | 34.2 | 2.24-2.32 (2H,m) | 1’; 2’; 4’; 5’; 7’ | - | - | - |
4’ | 133.9 | - | - | - | - | - |
5’ | 123.0 | 5.23-5.28 (1H,m) | 3’; 7’ | - | - | - |
6’ | 22.3 | 3.37 (2H, br d; 6.8) | 5; 7; 5’ | - | - | - |
7’ | 16.1 | 1.78 (3H, s) | 3’; 4’; 5’ | | - | - |
Abbreviations:
s - singlet,
br s - broad singlet,
br d - broad doublet,
m - multiplet.
Figure 2 1H NMR spectrum of mycophenolic acid (400 MHz, CDCl3).
The 1H NMR spectrum of the mycophenolic acid (Figure 2) showed signals for a methyl group at δ 1.78 (H-7', singlet, 3H) and a methyl group linked to aromatic ring at δ 2.13 (H-9, singlet, 3H), a signal for a methoxyl group at δ 3.74 (H-8, singlet, 3H), two signals corresponding to aliphatic methylenes in the region of δ 2.47 to δ 2.38 (H-3a' and H-3b', multiplet 2H), of δ 2.32 to δ 2.24 (H-2', multiplet, 2H), a broad doublet for a methylene group at δ 3.37 (H-6', 2H), a broad singlet at δ 5.18 (H-3, 2H) referring to an aliphatic methylene bearing oxygen, and a multiplet for a methyne group of δ 5.23 to δ 5.28 (H-5',1H).
Figure 4 gHMBC NMR experiment of 5-hydroxy-7-methoxy-4-methylphthalide (400 MHz, DMSO) and important long range correlations detected.
Print version ISSN 0001-3765
An. Acad. Bras. Ciênc. vol.85 no.2 Rio de Janeiro Apr./June 2013 Epub June 17, 2013
http://dx.doi.org/10.1590/S0001-37652013005000024
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