Resorcinol → 2-Bromoresorcinol

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°.

1. customwas removed by distillation
2. additionMeOH was added
3. distillationthe distillation
4. customwas removed
5. additionTo this was added a solution of NaOH (181.5 g) and Na2SO3 (573 g) in H2O (7.5 L)
6. extractionextracted with tert-butyl methyl ether (TBME) (2×1 L)
7. additionThe combined organic layers were treated with activated charcoal (20 g)
8. filtrationfiltered through Celite
9. washthe Celite was washed with an additional 500 mL of TBME
10. customThe solvent was then removed in vacuo
11. dissolutionThe resulting crude 2-bromoresorcinol was dissolved in a minimum amount of ethyl acetate
12. filtrationfiltered through silica gel eluting with a gradient from 20% to 40% ethyl acetate in hexanes

ORD-Eintrag

ord-c5e1af3c94b74f828f3fc3694104c8a4

Quelldatensatz

uspto-grants-2001_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06214869B1