Reaktion #47072

Reaktionsgleichung

4-fluorobenzaldehyde

2-methyl-cis-4,5-diphenyl-4,5-dihydro-imidazole-1-carboxylic acid, tert-butyl ester

2-Methyl-cis-4,5-diphenyl-4,5-dihydro-imidazole-1-carboxylic acid, tert-butyl ester

n-butyl lithium

hexane

ammonium chloride

→

product 256

Ausbeute 45.8%

2-[2-(4-Fluorophenyl)-2-hydroxyethyl]-cis-4,5-diphenyl-4,5-dihydro-imidazole-1-carboxylic acid, tert-butyl ester

Ausbeute 45.8%

Lösungsmittel

THF

EtOAc

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe mixture is stirred for 1 h at −70° C. and 1 h at RT
2. 2
   Sonstigethe organic layer is separated
3. 3
   Waschenwashed with brine
4. 4
   Trocknendried (MgSO4)
5. 5
   Filtrationfiltered
6. 6
   Sonstigethe residue purified by chromatography on silica gel
7. 7
   Waschenelution with dichloromethane:EtOAc (9:1)

Vorschrift

To a cold (−70° C.) solution of 2-methyl-cis-4,5-diphenyl-4,5-dihydro-imidazole-1-carboxylic acid, tert-butyl ester (253) (3.36 g, 10.0 mmol) in THF is added 1.6M n-butyl lithium in hexane (6.9 mL, 11.0 mmol), and the mixture is stirred for 1 h at −70° C. To the reaction mixture is added 4-fluorobenzaldehyde (1.18 mL, 11.0 mmol), and the mixture is stirred for 1 h at −70° C. and 1 h at RT. To the reaction mixture is added ammonium chloride solution, EtOAc, and the organic layer is separated, and washed with brine, dried (MgSO4), and filtered. The filtrate is rotary evaporated, and the residue purified by chromatography on silica gel; elution with dichloromethane:EtOAc (9:1) gives 2.11 g of the product 256. 1H NMR (CDCl3) δ 7.60-7.45 (m, 2 H), 7.15-6.90 (m, 10 H), 6.85-6.60 (m, 2 H), 5.70-5.20 (m, 4 H), 3.60-3.10 (m, 2 H), 1.18 (s, 9 H); MS: m/z 461 (M++1).

Quelle