Hydrochloric Acid → 4-Oxo-4-(4-pentanoylamino-phenyl)-butyric acid

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Reaction Steps

To a 2-dram vial was added pentanoyl chloride (0.040 mL, 0.00033 mol), 4-(4-amino-phenyl)-4-oxo-butyric acid, methyl ester (0.051 g, 0.00025 mol) (Example 1, Step (c)), dichloromethane (3 mL), and a 3.6 mmol amine per gram of 4-morpholinomethyl polystyrene resin (0.10 g, 0.00036 mol amine), the vial was tightly capped, and the mixture was shaken at room temperature for approximately 5 hours. To the mixture was added an excess of [Bis(2-aminoethyl)amino-ethyl]amino-methyl polystyrene resin, the vial was tightly capped, and the mixture was shaken at room temperature overnight. The mixture was gravity filtered into a clean 2-dram vial, and the solvent evaporated under a stream of nitrogen. The residue was dissolved in THF (3 mL), 1.0 M NaOH (0.5 mL, 0.0005 mol) was added, and the mixture was shaken overnight. Additional 1.0 M NaOH (0.25 mL, 0.00025 mol) was added, and the mixture was shaken overnight. To the mixture was added 1.0 M HCl (1.0 mL, 0.001 mol), and the two-phase mixture was shaken for 1 hour. The bottom layer was withdrawn by pipet, and the remaining organics were evaporated under a stream of nitrogen. The residue was dried in vacuo to give 0.054 g of 4-oxo-4-(4-pentanoylamino-phenyl)-butyric acid as a pink solid; mp 153-155° C.

Provenance & Evidence