Hydrochloric Acid → 3-(Dimethylamino)-1-(thiophen-2-yl)propan-1-one hydrochloride

A mixture of 8.18 g of 2-acetylthiophene, 6.66 g of dimethylamine hydrochloride, 2.9 g of paraformaldahyde and 0.31 g of concentrated hydrochloric acid in 20 ml of isopropanol was heated to reflux and stirredfor 6 hours. The mixture was then cooled to 0° and stirred for one hour more. The slurry was then filtered, and the solid was washed with cold ethanol. The washed solid was dried for 16 hours at 50° to obtain 12.5 g of 2-thienyl 2-dimethylaminoethyl ketone hydrochloride, as awhite solid. A 12.0 g portion of that intermediate product was stirred in 40 ml of ethanol at ambient temperature, and the pH of the solution was raised to 11-12 by slow addition of sodium hydroxide. A 1.03 g portion of sodium borohydride was added, and the mixture was stirred at ambient temperature for 4 hours. Then 7.5 ml of acetone was added, and the mixturewas stirred for 20 minutes more. The mixture was then concentrated by evaporation to a white slurry, and 120 ml of methyl t-butyl ether was added. The mixture was acidified to pH 1-1.5 by addition of concentrated hydrochloric acid, and the solution was stirred for ten minutes. The pH was then made basic to pH 12 by slow addition of sodium hydroxide.

1. temperaturewas heated
2. temperatureto reflux
3. temperatureThe mixture was then cooled to 0°
4. filtrationThe slurry was then filtered
5. washthe solid was washed with cold ethanol
6. customThe washed solid was dried for 16 hours at 50°

ORD-Eintrag

ord-12094b376de84de4b6ece1773c9e4e65

Quelldatensatz

uspto-grants-1998_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05744474