2-Bromopropane → Isopropyl 1-isopropyl-2-bromo-4-methyl-5-imidazolecarboxylate

Participants

Reaction Steps

To a solution of 2 g (8.1×10-3 moles) of isopropyl 2-bromo-4-methyl-5-imidazolecarboxylate in 20 ml of benzene was added 1.2 ml (8.2×10-3 moles) of diazabicycloundecane, followed by 1.0 g. (8.1×10-3 moles) of 2-bromopropane. The resulting mixture was heated to reflux overnight, cooled to room temperature and filtered. Concentration in vacuo gave a golden oil. This residue was purified by medium pressure liquid chromatography on silica gel to yield 1.6 g (70%) isopropyl 1-isopropyl-2-bromo-4-methyl-5-imidazolecarboxylate as a yellow oil, but only 466 milligrams (20%) of the desired product, isopropyl 2-bromo-3-isopropyl-4-methyl-5-imidazolecarboxylate (also a yellow oil), wherein S1 and S3 and R were all CH(CH3)2.

Provenance & Evidence