Melatonin → 2-Bromomelatonin

Participants

Reaction Steps

N-bromo succinimide (0.89 g, 5 mmol) was added to a solution of melatonin (1.16 g, 5 mmol) in acetic acid (20 mL). The reaction mixture was stirred under N2 at room temperature for 4 h, then cooled at 0° C., neutralized with a 50% solution of NaOH and extracted with ethyl acetate. The combined organic layers were washed with NaCl solution, dried (Na2SO4) and concentrated. Purification by flash chromatography (silica gel; ethyl acetate/cyclohexane 6:4) and crystallization gave 0.467 g (30% yield) of 4k as white solid, mp 141°-142° C. IR νmax : 3460, 3300, 1650. 1H NMR: 1.99 (s, 3H, COCH3); 2.92(t, 2H, β -CH2), 3.54(q, 2H, α-CH2), 3.86(s, 3H, OCH3), 5.53(br s, 1H, NH), 6.85-7.23(m, 3Harom), 8.15(br s, 1H, NHindole).

Provenance & Evidence