Reaktion #62817

Reaktionsgleichung

Na2CO3

1-methylcyclohexyl 2-(p-aminophenyl)-propionate

potassium thiocyanate

Br2

→

1-methylcyclohexyl 2-amino-α-methylbenzothiazole-6-acetate

Ausbeute 73.1%

Lösungsmittel

acetic acid

water ethyl acetate

acetic acid

—

petroleum ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas cooled
2. 2
   Filtrationfiltered through celite
3. 3
   Sonstigethe organic layer was then separated
4. 4
   Waschenwashed with water
5. 5
   Trocknendried over MgSO4
6. 6
   Sonstigefinally evaporated to dryness

Vorschrift

A stirred mixture of 20.9 g of 1-methylcyclohexyl 2-(p-aminophenyl)-propionate and 31.0 g of potassium thiocyanate in 150 ml of glacial acetic acid was heated in an oil bath at 50° C. and a solution of 25.6 g of Br2 in 15 ml of glacial acetic acid was added dropwise over 30 minutes. The mixture was stirred at 50° C. for an extra 30 minutes, then was cooled and poured into 1,000 ml of 3:2 water/ethyl acetate mixture. The resulting mixture was neutralized to pH 5-6 with solid Na2CO3 and filtered through celite, and the organic layer was then separated, washed with water, dried over MgSO4 and finally evaporated to dryness. Trituration of the residual oil with petroleum ether gave 18.62 g (73% yield) of 1-methylcyclohexyl 2-amino-α-methylbenzothiazole-6-acetate as creamy white crystals melting at 165°-167° C.

Quelle