Reaktion #65587

Reaktionsgleichung

1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluenesulfonate

thiotetronic acid

triethylamine

KBr

cyclododecyloxyacetic acid

→

3-(2-cyclododecyloxy-1-oxoethyl)-4-hydroxy-2(5H)-thiophenone

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeAfter 10 minutes the ice bath is removed
2. 2
   workup.STIRRINGto stir overnight
3. 3
   SonstigeThe reaction mixture is quenched with 1N HCl
4. 4
   SonstigeThe layers are separated
5. 5
   Waschenthe organic layer is washed twice with aqueous sodium bicarbonate
6. 6
   TrocknenThe organic phase is then dried over MgSO4
7. 7
   Sonstigethe dichloromethane evaporated
8. 8
   Sonstigechromatographed on acidic silica gel using 50% ether/hexanes
9. 9
   Sonstigerecrystallized from hexanes
10. 10
    Sonstigeto give a yellow solid

Vorschrift

To a solution of 0.37 g (3.2 mmol) of thiotetronic acid in 20 mL of dry dichloromethane at 0° C. is added 0.4 mL (2.9 mmol) of triethylamine followed by 0.11 g (0.9 mmol) of 4-dimethylaminopyridine. After stirring at 0° C. for 5 minutes, 0.7 g (2.9 mmol) of cyclododecyloxyacetic acid is added, followed by 1.35 g (3.2 mmol) of 1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluenesulfonate. After 10 minutes the ice bath is removed and the reaction mixture is allowed to stir overnight. The reaction mixture is quenched with 1N HCl. The layers are separated and the organic layer is washed twice with aqueous sodium bicarbonate and then twice with 2N HCl. The organic phase is then dried over MgSO4 and the dichloromethane evaporated. The residue is flash chromatographed on acidic silica gel using 50% ether/hexanes and then recrystallized from hexanes to give a yellow solid: m.p. 93°-95° C.; IR (KBr) 2920, 2840, 1690, 1660, 1580 cm-1 ; NMR (DMSO-d6) δ 1.2-1.6 (m, 10H), 3.4 (m, 1H), 3.95 and 4.4 (s, 2H), 4.6 (bs, 2H); MS (EI) M+340.

Quelle