methyl (2S)-piperidine-2-carboxylate;hydrochloride

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

Procedure: Triethylamine (22.15 ml) was added to a solution of (2S)-2-(methoxycarbonyl)piperidine hydrochloride (10 g) [see Preparation 24] and cyclohexylmethanesulfonyl chloride (16.42 g) [King. J. F. et al,. J. Am. Chem. Soc., 1992, 114(5), 1743-9] in dichloromethane (100 ml). The reaction mixture was stirred for 18 hours after which time the solvent was removed under reduced pressure and the residue diluted with ethyl acetate. The organic layer was washed with water, brine, dried over magnesium sulphate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 95:5 changing to 80:20, by volume, hexane:ethyl acetate to afford methyl (2S)-1-[(cyclohexylmethyl)sulfonyl]-2-piperidinecarboxylate (11.9 g) as a white solid. was removed under reduced pressure the residue diluted with ethyl acetate The organic layer was washed with water, brine dried over magnesium sulphate the solvent was removed under reduced pressure The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 95:5 changing to 80:20, by volume, hexane

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

Procedure: Thionyl chloride (161 ml) was added dropwise to a suspension of (2S)-2-piperidinecarboxylic acid L-tartrate (60 g) [see Preparation 1] in methanol (800 ml) at 0° C. The reaction mixture was stirred for 18 hours at room temperature after which time the solvent was removed under reduced pressure and the product azeotroped with toluene, precipitated out using methanol and filtered to afford (2S)-2-(methoxycarbonyl)piperidine hydrochloride (37.7 g) as a white solid. was removed under reduced pressure the product azeotroped with toluene precipitated out filtered

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

Procedure: (2S)-Piperidine-2-carboxylic acid methyl ester hydrochloride (625 mg) was dissolved in dichloromethane. Then N,N-diisopropylethylamine (0.91 ml) and benzaldehyde (0.53 ml) were added to the solution at 0° C. After the whole was stirred for 30 minutes at the same temperature, sodium triacetoxyborohydride (1.48 g) was added. The reaction mixture was allowed to room temperature and stirred for 3 hours. The mixture was poured into aqueous saturated sodium hydrogen carbonate solution and extracted with ethyl acetate. The extract was dried over magnesium sulfate and evaporated under reduced pressure to give (2S)-1-benzylpiperidine-2-carboxylic acid methyl ester (795 mg). was added was allowed to room temperature extracted with ethyl acetate The extract was dried over magnesium sulfate evaporated under reduced pressure

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Thionyl chloride (0.58 ml) was added dropwise to a solution of L-pipecolinic acid (450 mg) in methanol at room temperature. The reaction mixture was stirred at 55° C. for 2 hours. The whole mixture was evaporated under reduced pressure to give (2S)-piperidine-2-carboxylic acid methyl ester hydrochloride as a colorless oil. The whole mixture was evaporated under reduced pressure

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Thionyl chloride (0.58 ml) was added dropwise to a solution of L-pipecolinic acid (450 mg) in methanol at room temperature. The reaction mixture was stirred at 55° C. for 2 hours. The whole mixture was evaporated under reduced pressure to give (2S)-piperidine-2-carboxylic acid methyl ester hydrochloride as a colorless oil. The whole mixture was evaporated under reduced pressure

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

Procedure: Triethylamine (22.15 ml) was added to a solution of (2S)-2-(methoxycarbonyl)piperidine hydrochloride (10 g) [see Preparation 24] and cyclohexylmethanesulfonyl chloride (16.42 g) [King. J. F. et al,. J. Am. Chem. Soc., 1992, 114(5), 1743-9] in dichloromethane (100 ml). The reaction mixture was stirred for 18 hours after which time the solvent was removed under reduced pressure and the residue diluted with ethyl acetate. The organic layer was washed with water, brine, dried over magnesium sulphate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 95:5 changing to 80:20, by volume, hexane:ethyl acetate to afford methyl (2S)-1-[(cyclohexylmethyl)sulfonyl]-2-piperidinecarboxylate (11.9 g) as a white solid. was removed under reduced pressure the residue diluted with ethyl acetate The organic layer was washed with water, brine dried over magnesium sulphate the solvent was removed under reduced pressure The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 95:5 changing to 80:20, by volume, hexane

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

Procedure: Thionyl chloride (161 ml) was added dropwise to a suspension of (2S)-2-piperidinecarboxylic acid L-tartrate (60 g) [see Preparation 1] in methanol (800 ml) at 0° C. The reaction mixture was stirred for 18 hours at room temperature after which time the solvent was removed under reduced pressure and the product azeotroped with toluene, precipitated out using methanol and filtered to afford (2S)-2-(methoxycarbonyl)piperidine hydrochloride (37.7 g) as a white solid. was removed under reduced pressure the product azeotroped with toluene precipitated out filtered

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

Procedure: Triethylamine (22.15 ml) was added to a solution of (2S)-2-(methoxycarbonyl)piperidine hydrochloride (10 g) [see Preparation 24] and cyclohexylmethanesulfonyl chloride (16.42 g) [King. J. F. et al,. J. Am. Chem. Soc., 1992, 114(5), 1743-9] in dichloromethane (100 ml). The reaction mixture was stirred for 18 hours after which time the solvent was removed under reduced pressure and the residue diluted with ethyl acetate. The organic layer was washed with water, brine, dried over magnesium sulphate and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 95:5 changing to 80:20, by volume, hexane:ethyl acetate to afford methyl (2S)-1-[(cyclohexylmethyl)sulfonyl]-2-piperidinecarboxylate (11.9 g) as a white solid. was removed under reduced pressure the residue diluted with ethyl acetate The organic layer was washed with water, brine dried over magnesium sulphate the solvent was removed under reduced pressure The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 95:5 changing to 80:20, by volume, hexane

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

Procedure: To a vigorously stirred solution of (S)-pipecolic acid methyl ester hydrochloride (500 mg, 2.79 mmol) in dry DCM (10 mL) cooled in an ice-bath, was added dropwise Et3N (705 mg, 6.96 mmol) followed by 2-chlorobenzyl chloroformate (made from 2-chlorobenzyl alcohol using the method described in J. Med. Chem., 1998, 41, 1315–1343) (857 mg, 4.18 mmol). The resulting suspension was stirred at 0° C. for a further 0.75 h, diluted with ethyl acetate (30 mL) and poured into 1.0-M HCl (30 mL). The organic layer was separated and washed sequentially with 1.0-M HCl (20 mL), aq.NaHCO3 (20 mL) and brine (20 mL). The organic layer was then dried (NaSO4), filtered and concentrated under reduced pressure to give a colorless oil. The oil was purified by column chromatography (15% ethyl acetate in hexane) to give the title compound as a colorless viscous oil (824 mg, 95%): 1H NMR (400 MHz, CDCl3) 1.2–1.4 (1H, m), 1.4–1.6 (1H, m), 1.6–1.8 (3H, m), 2.2–2.3 (1H, m), 2.9–3.2 (1H, m), 3.7–3.8 (3H, m), 4.0–4.2 (1H, m), 4.8–5.0 (1H, m), 5.2–5.4 (2H, m), 7.2–7.3 (2H, m), 7.3–7.5 (2H, m) The organic layer was separated washed sequentially with 1.0-M HCl (20 mL) The organic layer was then dried (NaSO4) filtered concentrated under reduced pressure to give a colorless oil The oil was purified by column chromatography (15% ethyl acetate in hexane)

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

Procedure: To a stirred suspension of (S)-piperidine-2-carboxylic acid methyl ester hydrochloride salt (5.0 g, 27.8 mmol) in dichloromethane (DCM) (35 mL ) at 0° C. was added diisopropylethylamine (DIPEA) (10.1 mL, 58.4 mmol) followed by N-(benzyloxycarbonyloxy)succinimide (7.63 g, 30.6 mmol). The reaction mixture was allowed to warm to room temperature and stirred overnight. The residue was diluted with DCM and washed with 1.0-M HCl. The organic layer was washed with brine, dried(Na2SO4), filtered and concentrated in vacuo. The residue was purified by flash chromatography (20% ethyl acetate in hexane) to afford the title compound as a pale yellow oil (7.72, 100%): 1H NMR (400 MHz, CD3OD) δ 1.19–1.88 (5H, m), 2.15–2.28 (1H, m), 2.91–3.12 (1H, m), 3.70–3.73 (3H, 2s), 4.00–4.07 (1H, m), 4.82–4.87 (1H, m), 5.03–5.21 (2H, m), 7.24–7.39 (5H, m); 13C NMR (100 MHz, CD3OD) δ 22.0, 22.1 (CH2), 26.0, 26.1 (CH2), 28.1 (CH2), 43.4, 43.5 (CH2), 53.1 (CH3), 56.2, 56.5 (CH), 68.8, 68.9 (CH2), 129.2 (CH), 129.5 (CH), 129.9 (CH), 138.4 (C), 167.0 (CO), 173.7 (CO). washed with 1.0-M HCl The organic layer was washed with brine, dried(Na2SO4) filtered concentrated in vacuo The residue was purified by flash chromatography (20% ethyl acetate in hexane)

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

Procedure: (2S)-Piperidine-2-carboxylic acid methyl ester hydrochloride (625 mg) was dissolved in dichloromethane. Then N,N-diisopropylethylamine (0.91 ml) and benzaldehyde (0.53 ml) were added to the solution at 0° C. After the whole was stirred for 30 minutes at the same temperature, sodium triacetoxyborohydride (1.48 g) was added. The reaction mixture was allowed to room temperature and stirred for 3 hours. The mixture was poured into aqueous saturated sodium hydrogen carbonate solution and extracted with ethyl acetate. The extract was dried over magnesium sulfate and evaporated under reduced pressure to give (2S)-1-benzylpiperidine-2-carboxylic acid methyl ester (795 mg). was added was allowed to room temperature extracted with ethyl acetate The extract was dried over magnesium sulfate evaporated under reduced pressure

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Thionyl chloride (0.58 ml) was added dropwise to a solution of L-pipecolinic acid (450 mg) in methanol at room temperature. The reaction mixture was stirred at 55° C. for 2 hours. The whole mixture was evaporated under reduced pressure to give (2S)-piperidine-2-carboxylic acid methyl ester hydrochloride as a colorless oil. The whole mixture was evaporated under reduced pressure