(S)-1-Boc-3-benzylpiperazine

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 6.67 ml (16.68 mmol, 1.00 eq.) of a 2.5 N aq. NaOH-solution were added to a solution of 2.94 g (16.68 mmol) 2-(S)-Benzyl-piperazine in 80 ml tert-Butanol and 80 ml H2O. After cooling to 0° C. 3.64 g (16.68 mmol, 1.00 eq.) Boc-anhydride was added and the mixture was stirred at 0° C. for 2 h. Then the solution was warmed to r.t. and stirred overnight. After evaporating the tert-Butanol the mixture was extracted with CH2Cl2. The comb. org. fractions were dried over Na2SO4 and evaporated. Column chromatography (CH2Cl2/MeOH (10+1)) yielded 3.82 g (13.82 mmol, 82.87%) 3-(S)-Benzyl-piperazine-1-carboxylic acid tert-butyl ester as a clear oil. Then the solution was warmed to r.t. stirred overnight After evaporating the tert-Butanol the mixture was extracted with CH2Cl2 fractions were dried over Na2SO4 evaporated

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 6.67 ml (16.68 mmol, 1.00 eq.) of a 2.5 N aq. NaOH-solution were added to a solution of 2.94 g (16.68 mmol) 2-(S)-Benzyl-piperazine in 80 ml tert-Butanol and 80 ml H2O. After cooling to 0° C. 3.64 g (16.68 mmol, 1.00 eq.) Boc-anhydride was added and the mixture was stirred at 0° C. for 2 h. Then the solution was warmed to r.t. and stirred overnight. After evaporating the tert-Butanol the mixture was extracted with CH2Cl2. The comb. org. fractions were dried over Na2SO4 and evaporated. Column chromatography (CH2Cl2/MeOH (10+1)) yielded 3.82 g (13.82 mmol, 82.87%) 3-(S)-Benzyl-piperazine-1-carboxylic acid tert-butyl ester as a clear oil. Then the solution was warmed to r.t. stirred overnight After evaporating the tert-Butanol the mixture was extracted with CH2Cl2 fractions were dried over Na2SO4 evaporated

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 6.67 ml (16.68 mmol, 1.00 eq.) of a 2.5 N aq. NaOH-solution were added to a solution of 2.94 g (16.68 mmol) 2-(S)-Benzyl-piperazine in 80 ml tert-Butanol and 80 ml H2O. After cooling to 0° C. 3.64 g (16.68 mmol, 1.00 eq.) Boc-anhydride was added and the mixture was stirred at 0° C. for 2 h. Then the solution was warmed to r.t. and stirred overnight. After evaporating the tert-Butanol the mixture was extracted with CH2Cl2. The comb. org. fractions were dried over Na2SO4 and evaporated. Column chromatography (CH2Cl2/MeOH (10+1)) yielded 3.82 g (13.82 mmol, 82.87%) 3-(S)-Benzyl-piperazine-1-carboxylic acid tert-butyl ester as a clear oil. Then the solution was warmed to r.t. stirred overnight After evaporating the tert-Butanol the mixture was extracted with CH2Cl2 fractions were dried over Na2SO4 evaporated

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 6.67 ml (16.68 mmol, 1.00 eq.) of a 2.5 N aq. NaOH-solution were added to a solution of 2.94 g (16.68 mmol) 2-(S)-Benzyl-piperazine in 80 ml tert-Butanol and 80 ml H2O. After cooling to 0° C. 3.64 g (16.68 mmol, 1.00 eq.) Boc-anhydride was added and the mixture was stirred at 0° C. for 2 h. Then the solution was warmed to r.t. and stirred overnight. After evaporating the tert-Butanol the mixture was extracted with CH2Cl2. The comb. org. fractions were dried over Na2SO4 and evaporated. Column chromatography (CH2Cl2/MeOH (10+1)) yielded 3.82 g (13.82 mmol, 82.87%) 3-(S)-Benzyl-piperazine-1-carboxylic acid tert-butyl ester as a clear oil. Then the solution was warmed to r.t. stirred overnight After evaporating the tert-Butanol the mixture was extracted with CH2Cl2 fractions were dried over Na2SO4 evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: HCl (4.0 M solution with 1,4-dioxane, 45 mL, 180 mmol) was added to a stirring solution of tert-butyl (3S)-3-benzyl-1-piperazinecarboxylate (5.0 g, 18 mmol, Waterstone Technology, Carmel, Ind.) and CH2Cl2 (36 mL) at room temperature. After 16 h, the reaction mixture was concentrated to give 4.5 g (2S)-2-benzylpiperazine (4.5 g) as its dihydrochloride salt. The material was used in the next step without purification. the reaction mixture was concentrated

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 6.67 ml (16.68 mmol, 1.00 eq.) of a 2.5 N aq. NaOH-solution were added to a solution of 2.94 g (16.68 mmol) 2-(S)-Benzyl-piperazine in 80 ml tert-Butanol and 80 ml H2O. After cooling to 0° C. 3.64 g (16.68 mmol, 1.00 eq.) Boc-anhydride was added and the mixture was stirred at 0° C. for 2 h. Then the solution was warmed to r.t. and stirred overnight. After evaporating the tert-Butanol the mixture was extracted with CH2Cl2. The comb. org. fractions were dried over Na2SO4 and evaporated. Column chromatography (CH2Cl2/MeOH (10+1)) yielded 3.82 g (13.82 mmol, 82.87%) 3-(S)-Benzyl-piperazine-1-carboxylic acid tert-butyl ester as a clear oil. Then the solution was warmed to r.t. stirred overnight After evaporating the tert-Butanol the mixture was extracted with CH2Cl2 fractions were dried over Na2SO4 evaporated