Nitric Acid → 7-Bromo-6-nitro-2-piperazinylquinoline

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of 19 (70 mg, 0.29 mmol) and 1-Piperazinecarboxaldehyde (4 ml) was heated at 125° C. for 30 min. under argon. The mixture was then cooled and diluted with saturated aqueous NaHCO3. The aqueous phase was extracted with ether (3×) and the combined extractions were dried (MgSO4). Concentration yielded a residue which was immediately dissolved in THF (10 ml) and 4M H2SO4 (5 ml). The solution was then brought to reflux and stirred for 1 h. The solution was cooled and poured into 1M NaOH. The resulting suspension was then extracted twice with ether and the ether extracts were dried (MgSO4). Evaporation of the solvent afforded a material which was immediately dissolved in H2SO4 (5 ml). To this solution was added dropwise HNO3 (0.1 ml) at -10° C. The mixture was stirred 15 min. at -10° -0° C., poured onto ice, and diluted with 1M NaOH until basic. The mixture was then extracted with CH2Cl2 (3×), and the combined organic layers were dried (MgSO4). Concentration yielded the quipazine analogue 3 (47 mg, 48% from 19). 1H NMR d (ppm): 1.60 s (NH), 3.00 dd (CH2), 3.80 dd (CH2), 7.04 d (CH arom), 7.87 d (CH arom), 7.95 s (CH arom), 8.24 s (CH arom).

Provenance & Evidence