Ammonium Chloride → Tert-butyl 2-carbamoyl-5-(2,4-dichlorophenyl)-7-methylimidazo[1,2-a]pyrimidine-6-carboxylate

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Reaction Steps

To a stirred solution of 6-(tert-butoxycarbonyl)-5-(2,4-dichlorophenyl)-7-methylimidazo[1,2-a]pyrimidine-2-carboxylic acid (Example 155, Step 1, 500 mg, 1.18 mmol) in THF (10 mL) at room temperature was added PyBOP (787 mg, 1.78 mmol), HOBt (240 mg, 1.18 mmol), NH4Cl (95 mg, 1.78 mmol) and iPr2NEt (0.4 mL, 2.37 mmol). After 24 h, the reaction was concentrated under reduced pressure and diluted with EtOAc. The organic layer was washed with 1N HCl, 1N NaOH and brine prior to drying over anhydrous MgSO4. Filtration, concentration under reduced pressure and purification by silica gel chromatography afforded tert-butyl 2-carbamoyl-5-(2,4-dichlorophenyl)-7-methylimidazo[1,2-a]pyrimidine-6-carboxylate (560 mg, 100%) as a light yellow solid.

Provenance & Evidence