Reaction #481595

Reaction equation

dimethylformamide

2,5-bis-tert.-butyloxycarbonylamino-bromobenzene

2,5-bis-tert.-butyloxycarbonylaminobromobenzene

ether

t-butyl lithium

→

N-(4-tert.-butyloxycarbonylamino-2-formylphenyl)carbamic acid-tert.butyl ester

Solvents

water

water

Conditions

Workup

1. 1
   workup.ADDITIONthe addition the solution
2. 2
   workup.STIRRINGthe reaction mixture is stirred for an hour at −20° C
3. 3
   TemperatureAfter slow heating to room temperature the reaction mixture
4. 4
   Extractionthe aqueous phase is extracted with ether
5. 5
   Dryingthe organic phase is dried with magnesium sulfate
6. 6
   workup.DISTILLATIONThe solvent is distilled off in a rotary evaporator
7. 7
   Otherthe residue is purified on silica gel with petroleum ether/ethyl acetate (9:1)

Procedure

3.3 g (0.01 mol) 2,5-bis-tert.-butyloxycarbonylamino-bromobenzene from step A are dissolved in 100 ml of water-free tetrahydrofuran under argon. Gradually 17 ml of a 1.6 molar methyl lithium ether solution (0.03 mol) are added. The reaction mixture is cooled to −20° C. Subsequently 7 ml of 1.5 molar t-butyl lithium solution (0.01 mol) are added gradually. After ending the addition the solution is stirred for 30 minutes at −20° C. Subsequently 1.2 g of dimethylformamide (0.02 mol) are added and the reaction mixture is stirred for an hour at −20° C. After slow heating to room temperature the reaction mixture is hydrolyzed with water and then poured into ether, the aqueous phase is extracted with ether and then the organic phase is dried with magnesium sulfate. The solvent is distilled off in a rotary evaporator and the residue is purified on silica gel with petroleum ether/ethyl acetate (9:1).

Source