(2R)-2-methyl-1-methylsulfonylpiperazine

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

Procedure: Second step: To a stirred solution of carbonic acid ditrichloromethyl ester (triphosgene) (1.17 g, 3.95 mmol) in CH2Cl2 (20 mL) at −78° C., was added a solution of (R)-1-methanesulfonyl-2-methyl-piperazine (1.76 g, 9.9 mmol) and pyridine (1.60 mL, 20 mmol) in CH2Cl2 (20 mL) over 1 hour. The temperature was raised to RT, and stirring was continued over night. The organic phase was washed with H2O, dried over Na2SO4. Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1) yielded 1.70 g (71%) of (R)-4-methanesulfonyl-3-methyl-piperazine-1-carbonyl chloride as a light yellow solid. was continued over night The organic phase was washed with H2O dried over Na2SO4 Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1)

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

Procedure: Second step: To a stirred solution of carbonic acid ditrichloromethyl ester (triphosgene) (1.17 g, 3.95 mmol) in CH2Cl2 (20 mL) at −78° C., was added a solution of (R)-1-methanesulfonyl-2-methyl-piperazine (1.76 g, 9.9 mmol) and pyridine (1.60 mL, 20 mmol) in CH2Cl2 (20 mL) over 1 hour. The temperature was raised to RT, and stirring was continued over night. The organic phase was washed with H2O, dried over Na2SO4. Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1) yielded 1.70 g (71%) of (R)-4-methanesulfonyl-3-methyl-piperazine-1-carbonyl chloride as a light yellow solid. was continued over night The organic phase was washed with H2O dried over Na2SO4 Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1)

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

Procedure: First step: To a stirred solution of commercially available (R)-3-methyl-piperazine-1-carboxylic acid tert-butyl ester (8.78 g, 44 mmol) in CH2Cl2 (80 mL) at 0° C. were added Et3N (12.15 mL, 88 mmol) and methanesulfonyl chloride (5.09 mL, 66 mmol). Stirring was continued at RT overnight, the reaction was poured onto water and extracted with CH2Cl2. The combined organic phases were dried on Na2SO4 and concentrated under vacuo. The crude product was dissolved in CH2Cl2 (50 mL) and TFA (15 mL) was added. After 2 hours at RT, the volatiles were removed under vacuo, the crude was dissolved in CH2Cl2 and washed with aq. NaHCO3 (until pH=8). The organic phase was dried on Na2SO4 and concentrated under vacuo to yield 2.63 g (34%) of (R)-1-methanesulfonyl-2-methyl-piperazine as a light yellow oil. the reaction was poured onto water extracted with CH2Cl2 The combined organic phases were dried on Na2SO4 concentrated under vacuo The crude product was dissolved in CH2Cl2 (50 mL) TFA (15 mL) was added After 2 hours at RT the volatiles were removed under vacuo the crude was dissolved in CH2Cl2 washed with aq. NaHCO3 (until pH=8) The organic phase was dried on Na2SO4 concentrated under vacuo

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

Procedure: Second step: To a stirred solution of carbonic acid ditrichloromethyl ester (triphosgene) (1.17 g, 3.95 mmol) in CH2Cl2 (20 mL) at −78° C., was added a solution of (R)-1-methanesulfonyl-2-methyl-piperazine (1.76 g, 9.9 mmol) and pyridine (1.60 mL, 20 mmol) in CH2Cl2 (20 mL) over 1 hour. The temperature was raised to RT, and stirring was continued over night. The organic phase was washed with H2O, dried over Na2SO4. Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1) yielded 1.70 g (71%) of (R)-4-methanesulfonyl-3-methyl-piperazine-1-carbonyl chloride as a light yellow solid. was continued over night The organic phase was washed with H2O dried over Na2SO4 Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1)

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

Procedure: First step: To a stirred solution of commercially available (R)-3-methyl-piperazine-1-carboxylic acid tert-butyl ester (8.78 g, 44 mmol) in CH2Cl2 (80 mL) at 0° C. were added Et3N (12.15 mL, 88 mmol) and methanesulfonyl chloride (5.09 mL, 66 mmol). Stirring was continued at RT overnight, the reaction was poured onto water and extracted with CH2Cl2. The combined organic phases were dried on Na2SO4 and concentrated under vacuo. The crude product was dissolved in CH2Cl2 (50 mL) and TFA (15 mL) was added. After 2 hours at RT, the volatiles were removed under vacuo, the crude was dissolved in CH2Cl2 and washed with aq. NaHCO3 (until pH=8). The organic phase was dried on Na2SO4 and concentrated under vacuo to yield 2.63 g (34%) of (R)-1-methanesulfonyl-2-methyl-piperazine as a light yellow oil. the reaction was poured onto water extracted with CH2Cl2 The combined organic phases were dried on Na2SO4 concentrated under vacuo The crude product was dissolved in CH2Cl2 (50 mL) TFA (15 mL) was added After 2 hours at RT the volatiles were removed under vacuo the crude was dissolved in CH2Cl2 washed with aq. NaHCO3 (until pH=8) The organic phase was dried on Na2SO4 concentrated under vacuo

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

Procedure: Second step: To a stirred solution of carbonic acid ditrichloromethyl ester (triphosgene) (1.17 g, 3.95 mmol) in CH2Cl2 (20 mL) at −78° C., was added a solution of (R)-1-methanesulfonyl-2-methyl-piperazine (1.76 g, 9.9 mmol) and pyridine (1.60 mL, 20 mmol) in CH2Cl2 (20 mL) over 1 hour. The temperature was raised to RT, and stirring was continued over night. The organic phase was washed with H2O, dried over Na2SO4. Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1) yielded 1.70 g (71%) of (R)-4-methanesulfonyl-3-methyl-piperazine-1-carbonyl chloride as a light yellow solid. was continued over night The organic phase was washed with H2O dried over Na2SO4 Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1)

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

Procedure: First step: To a stirred solution of commercially available (R)-3-methyl-piperazine-1-carboxylic acid tert-butyl ester (8.78 g, 44 mmol) in CH2Cl2 (80 mL) at 0° C. were added Et3N (12.15 mL, 88 mmol) and methanesulfonyl chloride (5.09 mL, 66 mmol). Stirring was continued at RT overnight, the reaction was poured onto water and extracted with CH2Cl2. The combined organic phases were dried on Na2SO4 and concentrated under vacuo. The crude product was dissolved in CH2Cl2 (50 mL) and TFA (15 mL) was added. After 2 hours at RT, the volatiles were removed under vacuo, the crude was dissolved in CH2Cl2 and washed with aq. NaHCO3 (until pH=8). The organic phase was dried on Na2SO4 and concentrated under vacuo to yield 2.63 g (34%) of (R)-1-methanesulfonyl-2-methyl-piperazine as a light yellow oil. the reaction was poured onto water extracted with CH2Cl2 The combined organic phases were dried on Na2SO4 concentrated under vacuo The crude product was dissolved in CH2Cl2 (50 mL) TFA (15 mL) was added After 2 hours at RT the volatiles were removed under vacuo the crude was dissolved in CH2Cl2 washed with aq. NaHCO3 (until pH=8) The organic phase was dried on Na2SO4 concentrated under vacuo

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

Procedure: Second step: To a stirred solution of carbonic acid ditrichloromethyl ester (triphosgene) (1.17 g, 3.95 mmol) in CH2Cl2 (20 mL) at −78° C., was added a solution of (R)-1-methanesulfonyl-2-methyl-piperazine (1.76 g, 9.9 mmol) and pyridine (1.60 mL, 20 mmol) in CH2Cl2 (20 mL) over 1 hour. The temperature was raised to RT, and stirring was continued over night. The organic phase was washed with H2O, dried over Na2SO4. Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1) yielded 1.70 g (71%) of (R)-4-methanesulfonyl-3-methyl-piperazine-1-carbonyl chloride as a light yellow solid. was continued over night The organic phase was washed with H2O dried over Na2SO4 Concentration under vacuo and flash chromatography (SiO2, EtOAc/H, 1:1)

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

Procedure: First step: To a stirred solution of commercially available (R)-3-methyl-piperazine-1-carboxylic acid tert-butyl ester (8.78 g, 44 mmol) in CH2Cl2 (80 mL) at 0° C. were added Et3N (12.15 mL, 88 mmol) and methanesulfonyl chloride (5.09 mL, 66 mmol). Stirring was continued at RT overnight, the reaction was poured onto water and extracted with CH2Cl2. The combined organic phases were dried on Na2SO4 and concentrated under vacuo. The crude product was dissolved in CH2Cl2 (50 mL) and TFA (15 mL) was added. After 2 hours at RT, the volatiles were removed under vacuo, the crude was dissolved in CH2Cl2 and washed with aq. NaHCO3 (until pH=8). The organic phase was dried on Na2SO4 and concentrated under vacuo to yield 2.63 g (34%) of (R)-1-methanesulfonyl-2-methyl-piperazine as a light yellow oil. the reaction was poured onto water extracted with CH2Cl2 The combined organic phases were dried on Na2SO4 concentrated under vacuo The crude product was dissolved in CH2Cl2 (50 mL) TFA (15 mL) was added After 2 hours at RT the volatiles were removed under vacuo the crude was dissolved in CH2Cl2 washed with aq. NaHCO3 (until pH=8) The organic phase was dried on Na2SO4 concentrated under vacuo