Reaction #2186204

Reaction equation

3-Benzothiazol-2-yl-7-piperazin-1-yl-chromen-2-one

cesium carbonate

→

desired product

Yield 47.3%

3-Benzothiazol-2-yl-7-(4-methyl-piperazin-1-yl)-chromen-2-one

Yield 47.3%

Solvents

dichloromethane

DMF

Conditions

Workup

1. 1
   Temperaturecooled below 5° C.
2. 2
   workup.ADDITIONtreated with 1 eq (0.018 mL) Mel
3. 3
   Washwashed twice with ice-water
4. 4
   OtherThe organic phase is evaporated
5. 5
   Otherthe residue column chromatographed (silica gel, dichloromethane/EtOH 9:1)
6. 6
   OtherRecrystallization from methanol/dichloromethane

Procedure

100 mg (0.28 mmol) 3-Benzothiazol-2-yl-7-piperazin-1-yl-chromen-2-one were dissolved in 15 mL DMF and treated under argon with 183 mg (2 eq.) cesium carbonate, cooled below 5° C. and treated with 1 eq (0.018 mL) Mel. After stirring for 4 h, the reaction mixture is diluted with 100 mL dichloromethane and washed twice with ice-water. The organic phase is evaporated and the residue column chromatographed (silica gel, dichloromethane/EtOH 9:1). Recrystallization from methanol/dichloromethane yields 50 mg (47%) desired product as an orange powder.

Source