反应详情

3,5-Pyrazoledicarboxylic acid (840 mg, 5.4 mmol, 1.0 eq.), (R)-3-amino-4-(2-chloro-phenyl)-butyric acid ethyl ester (1.3 g, 5.4 mmol, 1.0 eq.), and HATU (2.0 g, 5.4 mmol, 1.0 eq.) were combined in DMF (5 mL) and mixed with sonication. DIPEA (1.9 mL, 10.8 mmol, 2.0 eq.) was added and the mixture was stirred for 1 hour at room temperature, then vacuumed to dryness. The crude product was dissolved in EtOH (25 mL), and concentrated H2SO4 (100 μL) was added. The mixture was stirred at 80° C. for 3 hours, then vacuumed to near dryness. EtOAc (200 mL) was added and the product was washed with NaHCO3 (100 mL) and then saturated aqueous NaCl (100 mL). The organic layer was retained and dried over anhydrous MgSO4 for 10 minutes prior to filtration and evacuation to dryness to yield 5-[(R)-1-(2-chloro-benzyl)-2-ethoxycarbonyl-ethylcarbamoyl]-2H-pyrazole-3-carboxylic acid ethyl ester, which was used without further purification (1.1 g).

1. additionmixed with sonication
2. stirringThe mixture was stirred at 80° C. for 3 hours
3. washthe product was washed with NaHCO3 (100 mL)
4. dry with materialdried over anhydrous MgSO4 for 10 minutes
5. filtrationto filtration and evacuation to dryness