5-(4-Bromophenyl)dipyrromethane synthesis

Yield:159152-11-1 92%

Reaction Conditions:

Stage #1: 4-bromo-benzaldehydewith indium(III) chloride;pyrrole for 1.5 h;
Stage #2: with sodium hydroxide for 0.75 h;

Steps:

Following the standard procedure,²³ 4-bromobenzaldehyde (5.55 g, 30.0 mmol) was dissolved in dry pyrrole (208 mL, 3.00 mol), and the solution was flushed with argon for 10 min. InCl₃ (666 mg, 3.00 mmol) was added, and the reaction was allowed to proceed for 90 min. The reaction was quenched by addition of powdered NaOH (3.60 g, 90.0 mmol). The mixture was stirred for 45 min. The mixture was filtered. The filtrate was concentrated at reduced pressure. Chromatography [silica, ethyl acetate/CH₂Cl₂/hexanes (1:2:7)] afforded a pale yellow solid (8.29 g, 92%): mp 120- 122 ⁰C; IR (film, v_max cm^"1) 1487; ¹H NMR δ 5.43 (s, IH), 5.88-5.89 (m, 2H), 6.15- 6.16 (m, 2H), 6.70-6.71 (m, 2H), 7.06-7.08 (m, 2H) 7.42-7.44 (m, 2H), 7.88-7.93 (br, 2H); ¹³C NMR δ 43.66, 107.65, 108.80, 112.61, 117.73, 121.08, 130.36, 131.92, 141.40; EI-MS 145, 234/236, 300/302; FAB-MS obsd 300.0257, calcd 300.0262 (C₁₅H₁₃BrN₂); Anal. Calcd C, 59.82; H, 4.53; N, 9.30. Found C, 59.99; H, 4.39; N, 9.19.

References:

WO2007/47925,2007,A2 Location in patent:Page/Page column 73; 94