Reaktion #417517

Reaktionsgleichung

water

4,4-dimethyl-6-bromothiochroman

tert-butyllithium

carbon dioxide

→

title compound

4,4-dimethyl-6-carboxythiochroman

Lösungsmittel

ether

pentane

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was warmed to room temperature
2. 2
   workup.DISSOLUTIONto dissolve the solids
3. 3
   SonstigeThe aqueous layer was then separated
4. 4
   Extraktionextracted with three portions of ether
5. 5
   Waschenwashed successively with water and saturated NaCl solution
6. 6
   Trocknendried (MgSO4)
7. 7
   FiltrationThe solution was filtered
8. 8
   Sonstigethe solvent removed in-vacuo
9. 9
   Sonstigethe residue recrystallized from ethyl acetate and hexane

Vorschrift

To a stirred solution of 5.14 g (0.02 mmol) of 4,4-dimethyl-6-bromothiochroman in 40 ml of dry ether at -78° C. was added dropwise 28.2 ml of 1.7 M 0.048 mmol) tert-butyllithium in pentane. The mixture was stirred at -78° C. for 2.5 hours and then treated with an excess of solid carbon dioxide. The mixture was warmed to room temperature and treated with sufficient water to dissolve the solids. The aqueous layer was then separated, acidified with dilute sulfuric acid and extracted with three portions of ether. The ether extracts were combined and washed successively with water and saturated NaCl solution and then dried (MgSO4). The solution was filtered and the solvent removed in-vacuo and the residue recrystallized from ethyl acetate and hexane to give the title compound as a white solid. PMR (CDCl3): δ1.37 (6H, s), 1.97 (2H, m), 3.08 (2H, m), 7.17 (1H, d, J~ 8.0 Hz), 7.74 (1H dd, J~8.0, 1.9 Hz), 8.11 (1H, d, J~1.9 Hz).

Quelle