methyl (2S)-4,4-difluoropyrrolidine-2-carboxylate

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated

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

Procedure: To a solution of 1.2 g 4-{(S)-4-tert-Butoxycarbonyl-2-[(5-carboxymethoxy-1-phenyl-1H-pyrazole-3-carbonyl)-amino]-butyryl}-piperazine-1-carboxylic acid ethyl ester in 35 ml DMF were added 278 mg HOAt, 1.6 g EDC, 1.1 ml DIPEA and 684 mg (S)-4,4-Difluoro-pyrrolidine-2-carboxylic acid methyl ester hydrotrifluoroacetate. After 36 h the mixture was diluted with ethyl acetate and subsequently extracted with aqueous LiCl (4% w/w), 0.1 M HCl and saturated aqueous NaHCO3. The organic layer was dried over MgSO4 and the solvent was removed under reduced pressure. The crude product thus obtained was purified by chromatography on silica using heptan/ethyl acetate 40/60 to 33/67 as eluent. subsequently extracted with aqueous LiCl (4% w/w), 0.1 M HCl and saturated aqueous NaHCO3 The organic layer was dried over MgSO4 the solvent was removed under reduced pressure

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

Procedure: To a solution of 650 mg (S)-4,4-Difluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester in 10 ml dichloromethane were added 1.5 ml TFA. After stirring for 12 h the solution was concentrated to give the crude hydrotrifluoroacetate. was concentrated to give the crude hydrotrifluoroacetate

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

Procedure: (S)-1-tert-butyl 2-methyl 4,4-difluoropyrrolidine-1,2-dicarboxylate (0.472 g) in CH2Cl2 (1 mL) was treated with trifluoroacetic acid (1.4 mL), stirred at ambient temperature for 4 hours, and concentrated. The product was free-based using a MEGA BE-SCX column with 1:1 CH2Cl2/methanol as eluent for the trifluoroacetic acid. The product was released from the column with 5% (7 M ammonia in methanol) in CH2Cl2 as eluent. concentrated