tert-butyl 4-(2,2,2-trifluoroethyl)piperazine-1-carboxylate

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

Procedure: A solution of hydrochloric acid (4.0 M, 10 mL) in dioxane was added to a solution of tert-butyl 4-(2,2,2-trifluoroethyl)piperazine-1-carboxylate (0.736 g, 2.74 mmol) in dioxane (5 mL). The reaction mixture was stirred until analysis by thin layer chromatography indicated completion of reaction (approx. 3 h). The volatiles were evaporated and the residue was dried under vacuum to yield 1-(2,2,2-trifluoroethyl)piperazine dihydrochloride (0.631 g, 95%) as a white solid. completion of reaction (approx. 3 h) The volatiles were evaporated the residue was dried under vacuum

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

Procedure: tert-Butyl 4-(2,2,2-trifluoroacetyl)piperazine-1-carboxylate (0.908 g, 3.22 mmol) was added to a solution of borane-tetrahydrofuran complex (8 mmol) in tetrahydrofuran (24 mL) and the reaction mixture was heated at reflux for 2 h. After cooling, 2 N hydrochloric acid (4 mL) was carefully added and the reaction mixture was stirred until gas evolution ceased and then diluted with ethyl acetate (200 mL). Aqueous sodium hydroxide (0.2 M, 75 mL) was then added and the phases were separated. The organic layer was dried over sodium sulfate and evaporated. The residue was purified by column chromatography (eluting with 20% ethyl acetate in hexanes) to give tert-butyl 4-(2,2,2-trifluoroethyl)piperazine-1-carboxylate (0.627 g, 73%) as a white solid. the reaction mixture was heated at reflux for 2 h After cooling the phases were separated The organic layer was dried over sodium sulfate evaporated The residue was purified by column chromatography (eluting with 20% ethyl acetate in hexanes)

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

Procedure: tert-Butyl 4-(2,2,2-trifluoroacetyl)piperazine-1-carboxylate (0.908 g, 3.22 mmol) was added to a solution of borane-tetrahydrofuran complex (8 mmol) in tetrahydrofuran (24 mL) and the reaction mixture was heated at reflux for 2 h. After cooling, 2 N hydrochloric acid (4 mL) was carefully added and the reaction mixture was stirred until gas evolution ceased and then diluted with ethyl acetate (200 mL). Aqueous sodium hydroxide (0.2 M, 75 mL) was then added and the phases were separated. The organic layer was dried over sodium sulfate and evaporated. The residue was purified by column chromatography (eluting with 20% ethyl acetate in hexanes) to give tert-butyl 4-(2,2,2-trifluoroethyl)piperazine-1-carboxylate (0.627 g, 73%) as a white solid. the reaction mixture was heated at reflux for 2 h After cooling the phases were separated The organic layer was dried over sodium sulfate evaporated The residue was purified by column chromatography (eluting with 20% ethyl acetate in hexanes)

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

Procedure: tert-Butyl 4-(2,2,2-trifluoroacetyl)piperazine-1-carboxylate (0.908 g, 3.22 mmol) was added to a solution of borane-tetrahydrofuran complex (8 mmol) in tetrahydrofuran (24 mL) and the reaction mixture was heated at reflux for 2 h. After cooling, 2 N hydrochloric acid (4 mL) was carefully added and the reaction mixture was stirred until gas evolution ceased and then diluted with ethyl acetate (200 mL). Aqueous sodium hydroxide (0.2 M, 75 mL) was then added and the phases were separated. The organic layer was dried over sodium sulfate and evaporated. The residue was purified by column chromatography (eluting with 20% ethyl acetate in hexanes) to give tert-butyl 4-(2,2,2-trifluoroethyl)piperazine-1-carboxylate (0.627 g, 73%) as a white solid. the reaction mixture was heated at reflux for 2 h After cooling the phases were separated The organic layer was dried over sodium sulfate evaporated The residue was purified by column chromatography (eluting with 20% ethyl acetate in hexanes)

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

Procedure: To 4-(2,2,2-trifluoro-acetyl)-piperazine-1-carboxylic acid tert-butyl ester (6.06 g) in dry THF (60 mL) was added borane dimethyl sulfide complex (4.5 ml) and the reaction mixture was heated to reflux. After 2 h the reaction mixture was cooled to 0° C. and MeOH was carefully added, followed by water. The organics were extracted into ethyl acetate, dried (MgSO4) and the solvent removed in vacuo to yield 4-(2,2,2-trifluoro-ethyl)-piperazine-1-carboxylic acid tert-butyl ester (4.46 g). Treatment with HCl in DCM/MeOH yielded the desired compound, which was isolated as the hydrochloride salt. the reaction mixture was heated to reflux The organics were extracted into ethyl acetate dried (MgSO4) the solvent removed in vacuo

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

Procedure: To 4-(2,2,2-trifluoro-acetyl)-piperazine-1-carboxylic acid tert-butyl ester (6.06 g) in dry THF (60 mL) was added borane dimethyl sulfide complex (4.5 ml) and the reaction mixture was heated to reflux. After 2 h the reaction mixture was cooled to 0° C. and MeOH was carefully added, followed by water. The organics were extracted into ethyl acetate, dried (MgSO4) and the solvent removed in vacuo to yield 4-(2,2,2-trifluoro-ethyl)-piperazine-1-carboxylic acid tert-butyl ester (4.46 g). Treatment with HCl in DCM/MeOH yielded the desired compound, which was isolated as the hydrochloride salt. the reaction mixture was heated to reflux The organics were extracted into ethyl acetate dried (MgSO4) the solvent removed in vacuo

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

Procedure: To 4-(2,2,2-trifluoro-acetyl)-piperazine-1-carboxylic acid tert-butyl ester (6.06 g) in dry THF (60 mL) was added borane dimethyl sulfide complex (4.5 ml) and the reaction mixture was heated to reflux. After 2 h the reaction mixture was cooled to 0° C. and MeOH was carefully added, followed by water. The organics were extracted into ethyl acetate, dried (MgSO4) and the solvent removed in vacuo to yield 4-(2,2,2-trifluoro-ethyl)-piperazine-1-carboxylic acid tert-butyl ester (4.46 g). Treatment with HCl in DCM/MeOH yielded the desired compound, which was isolated as the hydrochloride salt. the reaction mixture was heated to reflux The organics were extracted into ethyl acetate dried (MgSO4) the solvent removed in vacuo

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

Procedure: To 4-(2,2,2-trifluoro-acetyl)-piperazine-1-carboxylic acid tert-butyl ester (6.06 g) in dry THF (60 mL) was added borane dimethyl sulfide complex (4.5 ml) and the reaction mixture was heated to reflux. After 2 h the reaction mixture was cooled to 0° C. and MeOH was carefully added, followed by water. The organics were extracted into ethyl acetate, dried (MgSO4) and the solvent removed in vacuo to yield 4-(2,2,2-trifluoro-ethyl)-piperazine-1-carboxylic acid tert-butyl ester (4.46 g). Treatment with HCl in DCM/MeOH yielded the desired compound, which was isolated as the hydrochloride salt. the reaction mixture was heated to reflux The organics were extracted into ethyl acetate dried (MgSO4) the solvent removed in vacuo

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

Procedure: To 4-(2,2,2-trifluoro-acetyl)-piperazine-1-carboxylic acid tert-butyl ester (6.06 g) in dry THF (60 mL) was added borane dimethyl sulfide complex (4.5 ml) and the reaction mixture was heated to reflux. After 2 h the reaction mixture was cooled to 0° C. and MeOH was carefully added, followed by water. The organics were extracted into ethyl acetate, dried (MgSO4) and the solvent removed in vacuo to yield 4-(2,2,2-trifluoro-ethyl)-piperazine-1-carboxylic acid tert-butyl ester (4.46 g). Treatment with HCl in DCM/MeOH yielded the desired compound, which was isolated as the hydrochloride salt. the reaction mixture was heated to reflux The organics were extracted into ethyl acetate dried (MgSO4) the solvent removed in vacuo