TABLE 2.
1H NMR chemical shift values and coupling constants of metabolites formed from xylene degradationa
| Substrates | Intermediate |
1H NMR chemical shifts
|
||||||
|---|---|---|---|---|---|---|---|---|
| −CH3 | −CH2OH | H2 | H3 | H4 | H5 | H6 | ||
| o-Xylene + toluene | 4-Hydroxy-2-methylbenzoic acidb | 2.26 | 7.21 | 6.64 (3JH5-H6 = 8.3) | 6.61 | |||
| 2-Methylbenzoic acid | 2.25 | 7.18 (3JH3-H4 = 7.0) | 7.12 (3JH4-H5 = 7.0) | 7.14 (3JH5-H6 = 7.0) | 7.20 | |||
| o-Phthalic acid | 7.36 (3JH3-H4 = 7.0) | 7.29 (3JH4-H5 = 7.0) | 7.29 (3JH5-H6 = 7.0) | 7.36 | ||||
| m-Xylene + toluene | 3-Methylbenzoic acid | 2.30 | 7.63 | 7.30 (3JH4-H5 = 7.0) | 7.30 (3JH5-H6 = 7.0) | 7.60 | ||
| 3-Hydroxymethylbenzoic acidb | 4.65 | 7.73 | 7.42 (3JH4-H5 = 7.7) | 7.38 (3JH5-H6 = 7.6) | 7.71 | |||
| m-Phthalic acid | 8.17 | 7.87 (3JH4-H5 = 7.6, 4JH4-H6 = 1.3) | 7.41 (3JH5-H6 = 7.6) | 7.87 | ||||
a
Chemical shifts were determined relative to the HDO signal (4.7 ppm) at 23°C. Resonances which showed strong coupling were simulated and iteratively fitted onto the measured data.
b
Identified by two-dimensional NMR experiments with nuclear Overhauser spectroscopy.