1-benzyl-3,3-dimethylpiperidin-4-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: Sodium borohydride (0.456 g, 12.0 mmole) was added to the stirred solution of 1-benzyl-3,3-dimethylpiperidin-4-one [{prepared according to literature procedure described in U.S. Pat. No. 5,846,980} 5.4 g, 24.0 mmole] in methanol (25 ml) at 0-5° C. over a period of 15 min, and stirring was continued for 30 min. The reaction mixture was concentrated to dryness, triturated with water (25 ml) and extracted with ethyl acetate (2×100 ml). The extract was dried (sodium sulphate) and concentrated to dryness to furnish 1-benzyl-3,3-dimethyl-4-hydroxypiperidine as oil. Yield 5.2 g (96%), C14H2,NO, m/z 220 (M+1), PMR (CDCl3): 0.83 (3H, s, CH3), 1.13 (3H, s, CH3), 1.29 (1H, m, H5), 1.62-1.9 (2H, m, H2 & H5), 2.14 (1H, m, H6), 2.38 (1H, d, H2, j=12 Hz), 2.8 (1H, m, H6), 3.12 (1H, m, H4), 3.46 (2H, s, N—CH2), 7.3 (5H, m, ArH). prepared The reaction mixture was concentrated to dryness triturated with water (25 ml) extracted with ethyl acetate (2×100 ml) The extract was dried (sodium sulphate) concentrated to dryness

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a solution of 1-Benzyl-3-methyl-piperidin-4-one (2.03 g, 10 mmol) in THF (10 mL) was added potassium t-Butoxide (1.1 g, 10 mmol) and methyl iodide (0.62 mL, 10 mmol). The solution was then stirred at room temperature for about 72 hours. The reaction was quenched with brine and extracted with ethyl acetate. The combined organic layers were concentrated in vacuo, then purified by flash chromatography on silica gel (35 g SiO2, gradient elution from 100% hexane to 100% ethyl acetate) to yield the title compound as a colorless oil. The reaction was quenched with brine extracted with ethyl acetate The combined organic layers were concentrated in vacuo purified by flash chromatography on silica gel (35 g SiO2, gradient elution from 100% hexane to 100% ethyl acetate)

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

Procedure: To a solution of 1-Benzyl-3-methyl-piperidin-4-one (2.03 g, 10 mmol) in THF (10 mL) was added potassium t-Butoxide (1.1 g, 10 mmol) and methyl iodide (0.62 mL, 10 mmol). The solution was then stirred at room temperature for about 72 hours. The reaction was quenched with brine and extracted with ethyl acetate. The combined organic layers were concentrated in vacuo, then purified by flash chromatography on silica gel (35 g SiO2, gradient elution from 100% hexane to 100% ethyl acetate) to yield the title compound as a colorless oil. The reaction was quenched with brine extracted with ethyl acetate The combined organic layers were concentrated in vacuo purified by flash chromatography on silica gel (35 g SiO2, gradient elution from 100% hexane to 100% ethyl acetate)

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

Procedure: 1-Benzyl-3,3-dimethyl-4-piperidone 275 g (1.26 mol) prepared as per procedure described in U.S. Pat. No. 5,846,980, was dissolved in 1.0 L. methanol. The solution was transferred to a Parr reactor after adding 10% palladium on carbon (25 g). The reaction mixture was stirred under 300 psi hydrogen pressure at 60° C. until chromatography showed complete conversion. The reaction mixture was filtered and the residue washed with methanol (200 ml). The filtrate was concentrated to dryness to afford 3,3-dimethyl-4-piperidone (158 g) which was used as such for the preparation of either 4-benzyloxycarbonylamino-3,3-dimethylpiperidine or 4-t-butyloxycarbonylamino-3,3-dimethylpiperidine. 5,846,980, was dissolved in 1.0 L The reaction mixture was filtered the residue washed with methanol (200 ml) The filtrate was concentrated to dryness

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

Procedure: 1-Benzyl-3,3-dimethyl-4-piperidone (10.0 g, 46.0 mmol), was added to the stirred solution cyclopropylamine (13.1 g, 230.0 mmol) in methanol (150 ml) and stirred for 6 hr. Sodium cyanoborohydride (2.9 g, 46.0 mmol) was added to it and reaction mixture was stirred for 15 hr. The reaction mixture was concentrated to dryness, triturated with water, extracted with chloroform, dried (Na2SO4) and concentrated. The obtained crude product was purified over silica gel column. Eluted from 5% ethyl acetate in hexane gave 1-benzyl-4-cyclopropylamino-3,3-dimethyl piperidine. Yield 8.0 g (67.3%), C17H26N2, m/z 259 (M+1), PMR (CDCl3): 0.4 (m, 2H), 0.82 (s, 3H), 1.06 (s, 3H), 1.16 (m, 2H), 1.5 (bs, 1H, D2O exchangeable), 1.7 (m, 2H), 1.9-2.95 (m, 5H), 3.3-3.6 (m, 3H), 7.22 (m, 5H). was stirred for 15 hr The reaction mixture was concentrated to dryness triturated with water extracted with chloroform dried (Na2SO4) concentrated The obtained crude product was purified over silica gel column Eluted from 5% ethyl acetate in hexane

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

Procedure: Potassium hydroxide (4.6 g, 83.0 mmol) was added to the stirred solution of ethylamine hydrochloride (6.8 g, 83.0 mmol) in methanol (70 ml) and stirring was continued for 30 min at 30° C. 1-benzyl-3,3-dimethyl-4-piperidone (3.5 g, 16.6 mmol)), was added to the resulting mixture and stirred for 6 hr. Sodium cyanoborohydride (1.0 g, 16.6 mmol) was added to it and reaction mixture was stirred for 15 hr. The reaction mixture was concentrated to dryness, triturated with water, extracted with chloroform, dried (Na2SO4) and concentrated to give 1-benzyl-4-ethylamino-3,3-dimethylpiperidine. Yield 3.8 g (88%), C16H26N2, m/z 247 (M+1), PMR (CDCl3): 0.9 (s, 3H), 1.06 (s, 3H), 1.18-1.38 (m, 5H), 1.64-2.8 (m, 6H), 2.94 (m, 1H), 3.44 (dd, 2H), 7.2 (m, 5H). stirred for 6 hr was stirred for 15 hr The reaction mixture was concentrated to dryness triturated with water extracted with chloroform dried (Na2SO4) concentrated

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

Procedure: Potassium hydroxide (4.6 g, 83.0 mmol) was added to the stirred solution of ethylamine hydrochloride (6.8 g, 83.0 mmol) in methanol (70 ml) and stirring was continued for 30 min at 30° C. 1-benzyl-3,3-dimethyl-4-piperidone (3.5 g, 16.6 mmol)), was added to the resulting mixture and stirred for 6 hr. Sodium cyanoborohydride (1.0 g, 16.6 mmol) was added to it and reaction mixture was stirred for 15 hr. The reaction mixture was concentrated to dryness, triturated with water, extracted with chloroform, dried (Na2SO4) and concentrated to give 1-benzyl-4-ethylamino-3,3-dimethylpiperidine. Yield 3.8 g (88%), C16H26N2, m/z 247 (M+1), PMR (CDCl3): 0.9 (s, 3H), 1.06 (s, 3H), 1.18-1.38 (m, 5H), 1.64-2.8 (m, 6H), 2.94 (m, 1H), 3.44 (dd, 2H), 7.2 (m, 5H). stirred for 6 hr was stirred for 15 hr The reaction mixture was concentrated to dryness triturated with water extracted with chloroform dried (Na2SO4) concentrated

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

Procedure: Potassium hydroxide (12.85 g, 230 mmol) was added to the stirred solution of methylamine hydrochloride (15.5 g, 230.0 mmol) in methanol (100 ml) and stirring was continued for 30 min at 30° C. 1-Benzyl-3,3-dimethyl-4-piperidone (5 g, 23.0 mmol), was added to the resulting mixture and stirred for 6 hr. Sodium cyanoborohydride (1.45 g, 23.0 mmol) was added to it and reaction mixture was stirred for 15 hr. The reaction mixture was concentrated to dryness, triturated with water, extracted with chloroform, dried (Na2SO4) and concentrated to give 1-benzyl-4-methylamino-3,3-dimethylpiperidine. Yield 5.3 g (99%), C15H24N2, m/z 223 (M+1), PMR (CDCl3): 0.9 (s, 3H), 1.0 (s, 3H), 1.38 (m, 2H), 1.54 (bs, 1H, D2O exchangeable), 1.68-2.1 (m, 4H), 2.4 (s, 3H), 2.86 (m, 1H), 3.4 (dd, 2H), 7.3 (m, 5H). stirred for 6 hr was stirred for 15 hr The reaction mixture was concentrated to dryness triturated with water extracted with chloroform dried (Na2SO4) concentrated