Diisopropylethylamine → tert-Butyl (1-{4-[bromo(phenyl)acetyl]phenyl}cyclobutyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a mixture of crude tert-butyl (1-{4-[bromo(phenyl)acetyl]phenyl}cyclobutyl)carbamate [Int-1-A] (213 mg, 0.38 mmol, 1.0 eq), ethyl 5-aminopyrazine-2-carboxylate (CAS-Nr. 54013-06-8, 70.5 mg, 0.42 mmol, 1.1 eq.) and diisopropylethylamine (0.055 mL, 0.42 mmol, 1.1 eq) in 2.3 mL butyronitrile was added predried 3 Å mol sieves. The mixture was heated overnight at 120° C. The reaction mixture was partitioned between DCM/water and was filtered through a phase separator. The remaining volatile organic components were removed by the use of a rotary evaporator. In parallel we conducted the same experiment in the absence of diisopropylethylamine following the same protocol. The crude materials of both experiments were combined and purified via MPLC (Biotage Isolera, 25 g Snap-cartridge; eluent: hexane/ethyl acetate (1/1)→ethyl acetate) to deliver 69 mg (14%, yield based on combined amount of tert-butyl (1-{4-[bromo(phenyl)acetyl]-phenyl}cyclobutyl)carbamate) of the title compound.

Provenance & Evidence