Reaction #69976

Reaction equation

sodium hydrogencarbonate

4-{4-[4-(2-methoxyethanesulphonyl)piperazin-1-yl]phenyl}-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester

HCl

→

1-{4-[4-(2-methoxyethanesulphonyl)piperazin-1-yl]phenyl}-1,2,3,4-tetrahydro-quinoxaline

Yield 87.2%

Solvents

dichloromethane

dioxane

dichloromethane

Conditions

Workup

1. 1
   Otherto return to ambient temperature
2. 2
   workup.STIRRINGThe reaction mixture is stirred at ambient temperature for 18 h
3. 3
   ExtractionThe aqueous phase is extracted with dichloromethane
4. 4
   Washwashed with water
5. 5
   Dryingdried over sodium sulphate
6. 6
   Filtrationfiltered through a sintered glass
7. 7
   Filtrationfilter
8. 8
   Concentrationconcentrated under reduced pressure

Procedure

0.35 g of 4-{4-[4-(2-methoxyethanesulphonyl)piperazin-1-yl]phenyl}-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester is placed in 7 ml of dichloromethane. 2.5 ml of a 4N solution of HCl in dioxane are slowly added at 0° C. The mixture is stirred for 5 minutes under cold conditions and then the mixture is allowed to return to ambient temperature. The reaction mixture is stirred at ambient temperature for 18 h and is then diluted with dichloromethane. A saturated aqueous sodium hydrogencarbonate solution is added until a pH=7-8 is reached. The aqueous phase is extracted with dichloromethane. The organic phases are combined, washed with water, dried over sodium sulphate, filtered through a sintered glass filter and concentrated under reduced pressure. 0.246 g of 1-{4-[4-(2-methoxyethanesulphonyl)piperazin-1-yl]phenyl}-1,2,3,4-tetrahydro-quinoxaline is obtained in the form of an oil.

Source