Reaction #69970

Reaction equation

hydrochloric acid

4-[4-(4-(methanesulphonyl)piperazin-1-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid

→

1-[4-(4-(methanesulphonyl)piperazin-1-yl)phenyl]-1,2,3,4-tetrahydroquinoxaline

Solvents

dichloromethane

dioxane

Conditions

Workup

1. 1
   Otherthe solvents are evaporated under reduced pressure
2. 2
   workup.ADDITIONWater, a saturated aqueous sodium hydrogencarbonate solution and dichloromethane are added
3. 3
   ExtractionThe aqueous sodium phase is extracted twice with dichloromethane
4. 4
   Washwashed with water
5. 5
   Dryingdried over magnesium sulphate
6. 6
   Otherthe solvent is evaporated under reduced pressure

Procedure

31.5 g of the tert-butyl ester of 4-[4-(4-(methanesulphonyl)piperazin-1-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid are placed in 400 ml of dichloromethane and then 333 ml of 4N hydrochloric acid in dioxane are added. After stirring for 16 h under an inert atmosphere, the solvents are evaporated under reduced pressure. Water, a saturated aqueous sodium hydrogencarbonate solution and dichloromethane are added. The aqueous sodium phase is extracted twice with dichloromethane. The organic phases are combined, washed with water and dried over magnesium sulphate and then the solvent is evaporated under reduced pressure. 23.2 g of 1-[4-(4-(methanesulphonyl)piperazin-1-yl)phenyl]-1,2,3,4-tetrahydroquinoxaline are obtained. The product is subsequently used as is without other purification.

Source