Table 7. Compounds and Corresponding Aqueous pKa Values (with Citations to Their Sources) Used To Form the Initial Guanidine Training Seta.
| ID | compound | pKa |
|---|---|---|
| 1b | guanidine | 13.6049 |
| 2b | phenylbiguanide | 10.7150 |
| 3b | ethylenebis(biguanide) | 11.7650 |
| 4b | famitodine | 6.7851 |
| 5b | arginine | 12.5052 |
| 6b | N,N-dimethylguanidine | 13.4053 |
| 7b | N,N′,N″-trimethylguanidine | 13.9054 |
| 8b | hydroxyguanidine | 7.9655 |
| 9b | N″-benzoylcarbonohydrazonic diamide | 7.9455 |
| 10b | N″-phenylcarbonohydrazonicdiamide | 8.2655 |
| 11b | N′-(diaminomethylene)benzamide | 6.9855 |
| 12b | ethoxycarbonylguanidine | 7.0355 |
| 13b | methoxyguanidine | 7.4656 |
a
The equation for the linear fit used for predictions is pKa = 448.9 × r(C=N) – 561.15 and was obtained using the bond length data in Table S11.