Table 2. Acid Amine Coupling under Different Reaction Conditionsa.
| s. no | base | reagents | solvent | reaction condition | yield (%) |
|---|---|---|---|---|---|
| 1 | TEA | EDCI·HCl | DCM | 32 °C, 12 h | 65 |
| 2 | DMAP | DCC | DMF | 32 °C, 12 h | 77 |
| 3 | DMAP | EDCI·HCl | CHCl3 | 32 °C, 12 h, N2 | 76 |
| 4 | DMAP | EDCI·HCl | DCM | 32 °C, 12 h, N2 | 85 |
| 5 | TEA | DCC | Benzene | 32 °C, 12 h, N2 | 69 |
All reactions were carried out on a 100 mg scale. Acid (1.0 equiv), amine (1.0 equiv), base (2.0 equiv), reagent (2.0 equiv), and solvent (10 mL). TEA: triethylamine, EDCI·HCl: (3-dimethylamino-propyl)-ethyl-carbodiimide hydrochloride, DMAP: 4 dimethylaminopyridine, DCC: N,N′-dicyclohexylcarbodiimide, h: hour.