Resorcinol → 2-Bromoresorcinol

Beteiligte Stoffe

Reaktionsschritte

Bromine (0.363 L) was added dropwise over 2 hours to a solution of resorcinol (250 g) in dichloromethane (3.5 L). The solution was stirred at room temperature for 18 hours at which time approximately 1 L of the dichloromethane was removed by distillation. MeOH was added and the distillation continued in this manner until all of the dichloromethane was removed and the solution contained approximately 1.5 L of MeOH. To this was added a solution of NaOH (181.5 g) and Na2SO3 (573 g) in H2O (7.5 L). The resulting mixture was stirred at ambient temperature for 1 hour. The solution was then acidified to pH=2 with concentrated HCl (75 mL) and extracted with tert-butyl methyl ether (TBME) (2×1 L). The combined organic layers were treated with activated charcoal (20 g) and filtered through Celite; the Celite was washed with an additional 500 mL of TBME. The solvent was then removed in vacuo. The resulting crude 2-bromoresorcinol was dissolved in a minimum amount of ethyl acetate and filtered through silica gel eluting with a gradient from 20% to 40% ethyl acetate in hexanes yielding 2-bromoresorcinol (122 g). m.p. 86-88°.

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