Reaktion #65580

Reaktionsgleichung

3-cyclododecylpropanoic acid

KBr

1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride

thiotetronic acid

triethylamine

dimethylaminopyridine

→

3-(3-cyclododecyl-1-oxopropyl)-4-hydroxy-2(5H)-thiophenone

Lösungsmittel

hexane ethyl acetate

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeAfter 10 minutes the ice bath is removed
2. 2
   workup.STIRRINGto stir overnight at room temperature
3. 3
   workup.ADDITIONThe reaction mixture is then poured into 1N hydrochloric acid
4. 4
   Extraktionextracted 3 times with ethyl acetate
5. 5
   Waschenwashed with brine
6. 6
   Filtrationfiltered
7. 7
   Sonstigeevaporated
8. 8
   Sonstigeto give a brown oil
9. 9
   Sonstigeto give an off white solid

Vorschrift

To a solution of 0.80 g of thiotetronic acid in 20 ml of dry dimethylformamide at 0° C. is added 1.1 ml (836 mg, 8.3 mmol) of triethylamine and 0.31 g (2.5 mmol) of dimethylaminopyridine. After stirring for 5 minutes, 2.0 g (8.3 mmol) of 3-cyclododecylpropanoic acid is added followed by 1.6 g (8.3 mmol) of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride. After 10 minutes the ice bath is removed and the reaction mixture is allowed to stir overnight at room temperature. The reaction mixture is then poured into 1N hydrochloric acid and extracted 3 times with ethyl acetate. The organic layers are combined, washed with brine, filtered and evaporated to give a brown oil. The oil is subjected to flash chromatography using acidic silica gel and hexane/ethyl acetate (9:1) as the mobile phase to give an off white solid: m.p. 60°-62° C.; IR (KBr) 2940, 1700, 1630, and 1590 cm1 : NMR (CDCl3) δ 1.33 (bs, 22H), 1.49 (bs, 1H), 1.58 (m, 2H), 2.96 (m, 2H), 3.77 and 3.98 (singlets, 2H); MS (EI) M+338.

Quelle