8-methyl-1,4-dioxaspiro[4.5]decan-8-amine

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

Procedure: Dissolve 4-oxo-4-(2-oxo-oxazolidin-3-yl)-butyraldehyde (7.35 g, 42.96 mmol) in DCE (400 mL). Add 8-methyl-1,4-dioxa-spiro[4.5]dec-8-ylamine (7.36 g, 42.96 mmol), and acetic acid (2.58 g, 42.96 mmol) at room temperature under nitrogen. Stir the solution for one hour and then add sodium triacetoxyborohydride (18.21 g, 85.92 mmol). Stir the reaction mixture for over night and then add water (400 mL). Extract the aqueous layer with dichloromethane (3×400 mL). Combine the organic layers and dry with Na2SO4, filter, concentrate and purify by flash column chromatography (silica gel, 20-50% of EtOAc-Hexane) to give 0.92 g (9.0%) of 1-(8-Methyl-1,4-dioxa-spiro[4.5]dec-8-yl)-pyrrolidin-2-one as a colorless oil. at room temperature Stir the reaction mixture for over night Extract the aqueous layer with dichloromethane (3×400 mL) Combine the organic layers and dry with Na2SO4 filter concentrate purify by flash column chromatography (silica gel, 20-50% of EtOAc-Hexane)

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

Procedure: Dissolve (8-methyl-1,4-dioxa-spiro[4.5]dec-8-yl)-carbamic acid benzyl ester (13.12 g, 43.0 mmol) in MeOH (400 mL). Exchange air with nitrogen for three times and then add Pd—C (1.0 g, 10%). Exchange the nitrogen with H2 for three times. Stir the reaction mixture under H2 for over night then remove the Pd—C by filtration. Remove the solvent under reduced pressure to give 7.36 g (100%) of the crude 8-Methyl-1,4-dioxa-spiro[4.5]dec-8-ylamine as a colorless oil. then remove the Pd—C by filtration Remove the solvent under reduced pressure

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

Procedure: Dissolve (8-methyl-1,4-dioxa-spiro[4.5]dec-8-yl)-carbamic acid benzyl ester (13.12 g, 43.0 mmol) in MeOH (400 mL). Exchange air with nitrogen for three times and then add Pd—C (1.0 g, 10%). Exchange the nitrogen with H2 for three times. Stir the reaction mixture under H2 for over night then remove the Pd—C by filtration. Remove the solvent under reduced pressure to give 7.36 g (100%) of the crude 8-Methyl-1,4-dioxa-spiro[4.5]dec-8-ylamine as a colorless oil. then remove the Pd—C by filtration Remove the solvent under reduced pressure