Triethylamine → Tert-butyl 4-(4-amino-3-fluorobenzoyl)-2,2-dimethylpiperazine-1-carboxylate

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Reaction Steps

To tert-butyl 2,2-dimethylpiperazine-1-carboxylate (0.902 mmol, 0.193 g) in dichloro-methane (5 mL) was added 4-amino-3-fluorobenzoic acid (0.902 mmol, 0.14 g), and triethylamine (1.805 mmol, 0.252 mL, 0.183 g). To this mixture was added 1-propanephosphonic acid cyclic anhydride (1.805 mmol, 1.074 mL, 1.149 g, 50% solution in ethyl acetate). After 2 hours stirring, ethyl acetate was added and the organic mixture was washed with saturated sodium hydrogen carbonate, water, and saturated sodium chloride. The organic layer was dried with sodium sulfate, filtered and concentrated under vacuum to give the intermediate tert-butyl 4-(4-amino-3-fluorobenzoyl)-2,2-dimethylpiperazine-1-carboxylate (264 mg).

Provenance & Evidence