(5R)-5-(hydroxymethyl)-3,3-dimethylpyrrolidin-2-one

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

Procedure: To a stirred suspension of (R)-3,3,6,6-tetramethyltetrahydropyrrolo[1,2-c]oxazol-5(3H)-one (D35) (714 mg, 3.89 mmol) in MeOH (15 ml), p-TSA (74 mg, 0.39 mmol) was added and the resulting mixture was heated at reflux for 2 hrs. Solvent was evaporated off and the residue was loaded on SPE-SCX cartridge (5 g). The cartridge was washed with MeOH (3 column volume). The methanolic phase was collected and evaporated to afford the title compound (D36) (690 mg) was added the resulting mixture was heated at reflux for 2 hrs Solvent was evaporated off The cartridge was washed with MeOH (3 column volume) The methanolic phase was collected evaporated

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

Procedure: To a stirred suspension of (R)-3,3,6,6-tetramethyltetrahydropyrrolo[1,2-c]oxazol-5(3H)-one (D35) (714 mg, 3.89 mmol) in MeOH (15 ml), p-TSA (74 mg, 0.39 mmol) was added and the resulting mixture was heated at reflux for 2 hrs. Solvent was evaporated off and the residue was loaded on SPE-SCX cartridge (5 g). The cartridge was washed with MeOH (3 column volume). The methanolic phase was collected and evaporated to afford the title compound (D36) (690 mg) was added the resulting mixture was heated at reflux for 2 hrs Solvent was evaporated off The cartridge was washed with MeOH (3 column volume) The methanolic phase was collected evaporated

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

Procedure: Prepared according to US patent: 20070032433A1. To a solution of (R)-5-(hydroxymethyl)-3,3-dimethylpyrrolidin-2-one (2.91 g, 20.30 mmol) in THF (50.8 mL) cooled to 0° C., lithium aluminum hydride (2.0 M solution in THF, 12.18 mL, 24.36 mmol) was added. The mixture was stirred at room temperature overnight (16 h). Additional lithium aluminum hydride (2.0 M solution in THF, 12.18 mL, 24.36 mmol) was added and the solution was refluxed for 6 h. The reaction mixture was cooled and additional lithium aluminum hydride (2.0 M solution in THF, 12.18 mL, 24.36 mmol) was added and the mixture was refluxed overnight. The reaction mixture was cooled to 0° C. in an ice bath prior to addition of water (3.67 mL) followed by 15% aqueous NaOH (3.67 mL) and water (10.9 mL). It was then stir vigorously at room temperature for 1 h and filtered on a medium porosity sintered glass frit with cotton and celite washing with EtOAc. The solution was then concentrated affording crude (R)-(4,4-dimethylpyrrolidin-2-yl)methanol (2.29 g, 17.73 mmol, 87% yield) as yellow viscous oil. MS (ESI) 130.1 [M+H]+. Prepared the solution was refluxed for 6 h The reaction mixture was cooled the mixture was refluxed overnight The reaction mixture was cooled to 0° C. in an ice bath It was then stir vigorously at room temperature for 1 h filtered on a medium porosity sintered glass frit with cotton and celite washing with EtOAc The solution was then concentrated

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

Procedure: Prepared according to WO patent: 2013004290. To a solution of (R)-3,3,6,6-tetramethyltetrahydropyrrolo[1,2-c]oxazol-5(3H)-one (4.13 g, 22.54 mmol) in MeOH (90 mL) was added p-toluenesulfonic acid monohydrate (0.429 g, 2.254 mmol). The resulting mixture was heated at reflux for 2 h. The solvent was removed under reduced pressure (rotary evaporator) and the crude material was absorbed onto a plug of silica gel and purified by chromatography on an ISCO Combiflash™ RF (40 g Grace Reverlis column, using a gradient of 0-20% MeOH in DCM) affording (R)-5-(hydroxymethyl)-3,3-dimethylpyrrolidin-2-one (2.91 g, 20.31 mmol, 90% yield) as a white semi-solid. MS (ESI) 144.1 [M+H]+. Prepared The resulting mixture was heated at reflux for 2 h The solvent was removed under reduced pressure (rotary evaporator) the crude material was absorbed onto a plug of silica gel purified by chromatography on an ISCO Combiflash™ RF (40 g Grace Reverlis column

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

Procedure: Prepared according to WO patent: 2013004290. To a solution of (R)-3,3,6,6-tetramethyltetrahydropyrrolo[1,2-c]oxazol-5(3H)-one (4.13 g, 22.54 mmol) in MeOH (90 mL) was added p-toluenesulfonic acid monohydrate (0.429 g, 2.254 mmol). The resulting mixture was heated at reflux for 2 h. The solvent was removed under reduced pressure (rotary evaporator) and the crude material was absorbed onto a plug of silica gel and purified by chromatography on an ISCO Combiflash™ RF (40 g Grace Reverlis column, using a gradient of 0-20% MeOH in DCM) affording (R)-5-(hydroxymethyl)-3,3-dimethylpyrrolidin-2-one (2.91 g, 20.31 mmol, 90% yield) as a white semi-solid. MS (ESI) 144.1 [M+H]+. Prepared The resulting mixture was heated at reflux for 2 h The solvent was removed under reduced pressure (rotary evaporator) the crude material was absorbed onto a plug of silica gel purified by chromatography on an ISCO Combiflash™ RF (40 g Grace Reverlis column

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

Procedure: To a solution of (R)-5-hydroxymethyl-3,3-dimethyl-pyrrolidin-2-one (4.0 g, 28 mmol), prepared as described in Tetrahedron 1998, 54 10295-10307, and ethyl vinyl ether (4 mL, 42 mmol) in chloroform (26 mL), was added a catalytic amount of trifluoroacetic acid (0.056 mL), and the reaction mixture was stirred for four hours at room temperature. The solution was then washed with a saturated solution of sodium bicarbonate and brine, and dried over magnesium sulfate. The crude oil obtained after evaporating the solvent, was purified by chromatography on silica gel using hexane:ethyl acetate 1:1 as a solvent, giving 2.6 g of (R)-5-(1-ethoxy-ethoxymethyl)-3,3-dimethyl-pyrrolidin-2-one. The solution was then washed with a saturated solution of sodium bicarbonate and brine dried over magnesium sulfate The crude oil obtained after evaporating the solvent was purified by chromatography on silica gel

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

Procedure: To a stirred suspension of (R)-3,3,6,6-tetramethyltetrahydropyrrolo[1,2-c]oxazol-5(3H)-one (D35) (714 mg, 3.89 mmol) in MeOH (15 ml), p-TSA (74 mg, 0.39 mmol) was added and the resulting mixture was heated at reflux for 2 hrs. Solvent was evaporated off and the residue was loaded on SPE-SCX cartridge (5 g). The cartridge was washed with MeOH (3 column volume). The methanolic phase was collected and evaporated to afford the title compound (D36) (690 mg) was added the resulting mixture was heated at reflux for 2 hrs Solvent was evaporated off The cartridge was washed with MeOH (3 column volume) The methanolic phase was collected evaporated