Nitric Acid → 4-Chloro-8-nitroquinoline

Participants

Reaction Steps

4-Chloroquinoline (10.0 g, 61.3 mmol) was added in small portions to sulfuric acid (45 mL) taking care to maintain the temperature at or below 15° C. Then the solution was cooled and maintained at −5° C. during the addition of fuming nitric acid (9 mL). The mixture was allowed to warm to room temperature and stirred for an additional 3 h. The reaction mix was poured on ice and basified (pH 9) with NH4OH. The resulting precipitate was filtered, washed well with water, dried, and recrystallized from methanol to provide 7.5 g (59%) of 6a as golden-brown needles; mp 128-129° C. (lit.32mp 129-130° C.); 1H NMR (CDCl3) δ 7.67 (d, 1H, J=4.5), 7.75 (dd, 1H, J=8.6, J=7.6), 8.10 (dd, 1H, J=7.6, J=1.3), 8.48 (dd, 1H, J=8.6, J=1.3), 8.94 (d, 1H, J=4.5); 13C NMR (CDCl3) δ 123.0, 124.4, 126.5, 127.5, 128.3, 140.6, 143.2, 148.7, 152.1. The mother liquor was evaporated and chromatographed in 19:1 hexanes-ethyl acetate, to provide 2.05 g (16%) of the 5-nitro isomer 6d as a very light yellow solid; mp 144-146° C. (lit.31 mp 150° C.); 1H NMR (CDCl3) δ 7.65 (d, 1H, J=4.7), 7.82 (m, 2H), 8.35 (dd, 1H, J=2.5, J=7.3), 8.90 (d, 1H, J=4.7); 13C NMR (CDCl3) δ 118.2, 123.4, 125.1, 128.8,134.2,135.6, 139.1,149.7,151.2.

Provenance & Evidence