Ethylamine → Benzyl tert-butyl tetrahydropyridazine-1,2-dicarboxylate

Participants

Reaction Steps

To a solution of 0.1 g (0.42 mmol) 4-fluorophenylalanine tert-butyl ester in 1.0 mL of CH2Cl2 at 0° C. was added 0.065 g (0.5 mmol) of dilsopropyl ethyl amine followed by 0.093 g (0.46 mmol) of p-nitrophenyl chloroformate as a solid. After 30 minutes a solution of 82.7 mg (0.52 mmol) of pyridazine dihydrochloride (Step C) and 0.2 g (1.56 mmol) of diisopropylethylamine in 1.5 mL of CH2Cl2 was added. The reaction mixture was stirred for 2.5 hours and diluted with 20 mL of ethyl acetate. The solution was washed with water twice followed by brine and was dried over MgSO4. The mixture was filtered and concentrated in vacuo. The residue was purified by flash silica gel chromatography eluting with 45% EtOAc/hexanes to provide the title compound. 1H-NMR (CDCl3, 400 MHz): 1.38 (s, 9H); 1.60 (b, 6H); 2.8 (b, 2H); 3.05 (m, 2H); 15 4.57 (m, 1H); 6.75 (b, 1H); 6.95 (m, 2H); 7.15 (m, 2H).

Provenance & Evidence