反应详情

3.36 g (13.1 mmol) of 1,4-dibenzyl-2-aminomethylpiperazine prepared according to a protocol identical to the one used in steps 6.1 and 6.2 of Example 6 are dissolved in 5.5 ml (3 equivalents; 39.3 mmol) of triethylamine and 100 ml of dichloromethane and are treated by rapid dropwise addition of 2.63 ml (1.5 equivalents; 19.6 mmol) of 2,2-dimethylpropanoyl chloride dissolved in 30 ml of CH2Cl2. The solution is refluxed for 4 hours. A few ml of ethanol are then added, after which the solution is washed twice with water, once with saturated NaHCO3 solution and then with water until a neutral pH is obtained. After drying the organic phase (MgSO4), filtration on paper and evaporation of the solvents, the residue is chromatographed on a column of silica gel, eluting with an MeOH/CH2Cl2 mixture (0.5/99.5 v/v). 2.44 g of 1,4-dibenzyl-2-tert-butylcarbonylaminomethylpiperazine are thus obtained in the form of a viscous product. Yield: 49%. Rf═0.36 (95/5 v/v CH2Cl2/MeOH).

1. temperatureThe solution is refluxed for 4 hours
2. washafter which the solution is washed twice with water, once with saturated NaHCO3 solution
3. customwith water until a neutral pH is obtained
4. customAfter drying
5. filtrationthe organic phase (MgSO4), filtration
6. customon paper and evaporation of the solvents
7. customthe residue is chromatographed on a column of silica gel
8. washeluting with an MeOH/CH2Cl2 mixture (0.5/99.5 v/v)