N-bromobutanimide → 1-PIPERAZINECARBOXYLIC ACID, 4-(5-BROMOPYRAZINYL)-, 1,1-DIMETHYLETHYL ESTER

Participants

Reaction Steps

A 500-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with acetonitrile (150 mL), 189a (3.0 g, 8.8 mmol), and N-bromosuccinimide (1.56 g, 8.8 mmol). The mixture was stirred at room temperature overnight. It was then concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with 10:1 petroleum ether/ethyl acetate to afford 189b as a yellow solid (2.85 g, 73.4%). MS: [M+H]+ 343.3. 1H NMR (500 MHz, (CD3)2CO) δ 8.03 (s, 1H), 7.94 (s, 1H), 3.48-3.46 (m, 4H), 3.42-3.40 (m, 4H), 1.33 (s, 9H).

Provenance & Evidence