Reaktion #2286293

Reaktionsgleichung

hydrochloric acid

lithium aluminum hydride

(3,5-dichloro-4-hydroxy-phenyl)-acetic acid methyl ester

(3,5-Dichloro-4-hydroxy-phenyl)-acetic acid methyl ester

→

2,6-dichloro-4-(2-hydroxy-ethyl)-phenol

Ausbeute 100.1%

2,6-Dichloro-4-(2-hydroxy-ethyl)-phenol

Ausbeute 100.1%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONafter the addition
2. 2
   Sonstigewas quenched at −10° C. by the dropwise addition of a 10% aqueous Rochelle's Salt solution (80 mL)
3. 3
   workup.STIRRINGThe reaction suspension was stirred 10 min
4. 4
   workup.ADDITIONEthyl acetate (100 mL) was then added to the suspension
5. 5
   FiltrationThe mixture was then filtered
6. 6
   WaschenThe solids were rinsed with ethyl acetate (2×500 mL)
7. 7
   SonstigeThe organic layer was separated
8. 8
   ExtraktionThe aqueous layer was extracted with ethyl acetate (2×200 mL)
9. 9
   Waschenwashed with a 0.1N aqueous hydrochloric acid solution, water
10. 10
    TrocknenThe organic layer was dried with magnesium sulfate
11. 11
    Filtrationfiltered
12. 12
    Einengenconcentrated
13. 13
    Sonstigeto afford the first crop of solid
14. 14
    Sonstigewas placed under high vacuum overnight
15. 15
    Extraktionwas then re-extracted with ethyl acetate (3×200 mL)
16. 16
    Waschenwashed with water
17. 17
    TrocknenThe organic layer was dried with magnesium sulfate
18. 18
    Filtrationfiltered
19. 19
    Einengenconcentrated
20. 20
    Sonstigewas placed under high vacuum overnight

Vorschrift

A solution of (3,5-dichloro-4-hydroxy-phenyl)-acetic acid methyl ester (15) (15.7 g, 67.09 mmol) in anhydrous tetrahydrofuran (600 mL) under argon cooled to −10° C. was treated slowly dropwise with a 1 M solution of lithium aluminum hydride in tetrahydrofuran (67.1 mL, 67.1 mmol). The reaction mixture was stirred for 5 min after the addition was complete and was quenched at −10° C. by the dropwise addition of a 10% aqueous Rochelle's Salt solution (80 mL). The reaction suspension was stirred 10 min. Ethyl acetate (100 mL) was then added to the suspension. The mixture was then filtered. The solids were rinsed with ethyl acetate (2×500 mL). The organic layer was separated. The aqueous layer was extracted with ethyl acetate (2×200 mL). The organic layers were combined and washed with a 0.1N aqueous hydrochloric acid solution, water, and a saturated aqueous sodium chloride solution. The organic layer was dried with magnesium sulfate, filtered and concentrated to afford the first crop of solid. The resulting solid was placed under high vacuum overnight. The aqueous layer was acidified to pH=5 by the addition of a 1N aqueous hydrochloric acid solution and was then re-extracted with ethyl acetate (3×200 mL). The organic layers were combined and washed with water and a saturated aqueous sodium chloride solution. The organic layer was dried with magnesium sulfate, filtered and concentrated. The resulting solid was placed under high vacuum overnight to afford 2,6-dichloro-4-(2-hydroxy-ethyl)-phenol (16) (13.9 g, 100%); LRMS for C8H8Cl2O2 (M+) m/z=207 Molecular Weight=207.0578; Exact Mass=205.9901

Quelle