Iodine → 6-Fluorophenanthridine

A solution containing phenanthridine (1.0 g, 5.6 mmol) and iodine (1.4 g, 5.6 mmol) in CF2ClCFCl2 (30 ml) was placed in a fluorination apparatus fitted with a drying tube filled with soda lime. Elemental fluorine (7 mmol) as a 10% mixture in dry nitrogen was then passed through the stirred solution using narrow bore PTFE tubing at ca. 15 ml/min. After the fluorine had been added the solution was poured into 10% aqueous sodium metabisulfite solution (30 ml) and extracted with dichloromethane. The organic extracts were dried and evaporated to an orange oil (0.91 g). GC/MS analysis showed a 17% conversion of starting material. Column chromatography on silica get with dichloromethane as eluant gave 6-fluoro-phenanthridine (0.09 g, 48%); RF 0.78 (CH2Cl2); δH (400 MHz, CDCl3, Me4Si) 7.61 ppm (1H, d d d, JH1,H2 =JH2,H3 =7.8, JH2,H4 1.2, H-2), 7.69 (2H, m, H-3 and H-9), 7.88 (1H, d d d, JH7,H8 8.4, JH8,H9 7.2, JH8,H10 1.4, H-8), 7.97 (1H, d d, JH3,H4 8.0, JH2,H4 1.2, H-4), 8.21 (1H, d d, JH9,H10 8.0, JH8,H10 1.4, H-10 8.45 (1H, d d, JH1,H2 8.0, JH1,H3 0.8, H-1), 8.52 (1H, d d, JH7,H8 8.4, JH7,H9 1.2, H-7); δF (376 MHz. CDCl3, CFCl3) -68.2 ppm (s); δC (100 MHz, CDCl3, Me4Sl) 117.3 ppm (d, J 35.1,C-6a), 122.2 (d, 3J 3.8, C-7), 122.2 (s, C-1), 123.9 (d, 4J 1.9, C-10b), 124.2 (s, C-10), 126.5 (d, 6J 2.3, C-2), 127.9 (s, C-9), 128.7 (d, 4J 1.6, C-4), 129.4 (s, C-3), 132.1 (s, C-8), 136.5 (d, 3J 7.2, C-10a), 141.5 (d, 3J 17.9, C-4a), 158.1 (d, 1J 248.7, C-6); m/z (E1+) 197 (M+, 100%).