| dH = 0.23 + S(constants) | |
|
|
| Substituent | Constant |
| -R | 0.47 |
| -C=C | 1.32 |
| -C,C triple bond | 1.44 |
| -C6H5 | 1.85 |
| -NR2 | 1.57 |
| -NHC(O)R | 2.27 |
| -NO2 | 3.80 |
| -SR | 1.64 |
| -C(O)R | 1.70 |
| -C(O)C6H5 | 1.84 |
| -OH | 2.56 |
| -OR | 2.36 |
| -OC(O)R | 3.13 |
| -OC6H5 | 3.23 |
| -F | 4.00 |
| -Cl | 2.53 |
| -Br | 2.33 |
| -I | 1.82 |
| -CO2R | 1.55 |
| -C(O)NR2 | 1.59 |
| -CN | 1.70 |
*These calculations will work for methyl and methyne protons also, but best results are obtained for methylene protons.
 |
|
| dH = 0.23 + 2.53 + 2.53 | = 5.29 ppm |
| Observed: | 5.30 ppm |
 |
|
| dH = 0.23 + 1.85 + 3.13 | = 5.21 ppm |
| Observed: | 5.10 ppm |
 |
|
| dH = 0.23 + 0.47 + 2.53 + 1.70 | = 4.93 ppm |
| Observed: | 5.11 ppm |
 |
|
| dH = 0.23 + 3.80 + 0.47 | = 4.50 ppm |
| Observed: | 4.38 ppm |
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