Hydrochloric Acid → 3-(Bromomethyl)benzaldehyde

Participants

Reaction Conditions

Reaction Steps

A solution of diisobutylaluminum hydride (92 ml, 1M in hexanes, 92 mmol) was added dropwise via syringe pump injector over a period of 45 min to a solution of α-bromo-m-tolunitrile (15.000 g, 76.5 mmol) in 155 ml of chlorobenzene at 0° C. The resulting mixture was stirred at 0° C. for 1 h, then 100 ml of 10% aqueous HCl was added and stirring continued at 0° C. for 10 min. The layers were separated and the aqueous layer extracted with ether (2x). The organic solutions were combined and washed vigorously with 10% HCl for 10 min, then water (2x) and brine, dried over MgSO4 and evaporated to give a crystalline solid which was then dissolved in a minimal amount of ether (10-15 ml) and layered with petroleum ether (30-40 ml). The resulting spiny white crystals were collected and washed with ice-cold petroleum ether to yield 10.791 g (71%) of aldehyde 1: m.p. 46°-49° C.; 1H NMR δ 4.54 (s, 1, CH2Br), 7.52 (t, 1, J=8 Hz, H-5), 7.67 (br d, 1, J=8 Hz, H-4), 7.82 (dt, 1, J=8, 1 Hz, H-6), 7.90 (br s, 1, H-2), 10.02 (s, 1, CHO); 13C NMR δ 32.0 (CH2Br), 129.6, 129.7 and 129.8 (C-2, C-5 and C-6), 134.8 (C-4), 136.8 (C-1), 138.9 (C-3), 191.6 (CHO); IR ν 1595 and 1610 (m, C=C), 1710 (s, C=O), 2740 and 2820 (m, CHO) cm-1.

Provenance & Evidence