1,3-diazaspiro[4.5]decane-2,4,8-trione

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

Procedure: To a suspension of 1,3-diazaspiro[4.5]decane-2,4,8-trione (5.00 g, 27.4 mmol) in MeOH (91 mL) was added ammonium acetate (6.35 g, 82 mmol), and the mixture was stirred at RT for 25 minutes. To the suspension was added sodium cyanoborohydride (5.17 g, 82 mmol), and the mixture was stirred at RT. After 90 minutes, the flask was cooled, and the contents were quenched by careful addition of aqueous concentrated HCl, adjusting the pH to 7 with solid NaHCO3. The mixture was filtered through a pad of Celite® brand filter aid and concentrated in vacuo. The material was used directly in the next step. the mixture was stirred at RT After 90 minutes the flask was cooled the contents were quenched by careful addition of aqueous concentrated HCl The mixture was filtered through a pad of Celite® brand filter aid concentrated in vacuo

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

Procedure: A suspension of 9,12-dioxa-1,3-diazadispiro[4.2.4.2]tetradecane-2,4-dione (6.33 g, 28.0 mmol) in HCl (6N) (28 mL, 168 mmol) and EtOH (66.0 mL) was stirred at RT for 18 hours. The mixture was partially evaporated (about ½ volume), cooled in an ice bath and brought to a pH of approximately 10. The aqueous layer was extracted with DCM (2×200 mL), and the aqueous layer concentrated. The residue was triturated with THF (2×100 mL), and solids were removed by filtration. The filtrate was evaporated to afford the title compound as a white solid. The mixture was partially evaporated (about ½ volume) cooled in an ice bath The aqueous layer was extracted with DCM (2×200 mL) the aqueous layer concentrated The residue was triturated with THF (2×100 mL), and solids were removed by filtration The filtrate was evaporated

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

Procedure: A suspension of 9,12-dioxa-1,3-diazadispiro[4.2.4.2]tetradecane-2,4-dione (6.33 g, 28.0 mmol) in HCl (6N) (28 mL, 168 mmol) and EtOH (66.0 mL) was stirred at RT for 18 hours. The mixture was partially evaporated (about ½ volume), cooled in an ice bath and brought to a pH of approximately 10. The aqueous layer was extracted with DCM (2×200 mL), and the aqueous layer concentrated. The residue was triturated with THF (2×100 mL), and solids were removed by filtration. The filtrate was evaporated to afford the title compound as a white solid. The mixture was partially evaporated (about ½ volume) cooled in an ice bath The aqueous layer was extracted with DCM (2×200 mL) the aqueous layer concentrated The residue was triturated with THF (2×100 mL), and solids were removed by filtration The filtrate was evaporated

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

Procedure: To a suspension of 1,3-diazaspiro[4.5]decane-2,4,8-trione (5.00 g, 27.4 mmol) in MeOH (91 mL) was added ammonium acetate (6.35 g, 82 mmol), and the mixture was stirred at RT for 25 minutes. To the suspension was added sodium cyanoborohydride (5.17 g, 82 mmol), and the mixture was stirred at RT. After 90 minutes, the flask was cooled, and the contents were quenched by careful addition of aqueous concentrated HCl, adjusting the pH to 7 with solid NaHCO3. The mixture was filtered through a pad of Celite® brand filter aid and concentrated in vacuo. The material was used directly in the next step. the mixture was stirred at RT After 90 minutes the flask was cooled the contents were quenched by careful addition of aqueous concentrated HCl The mixture was filtered through a pad of Celite® brand filter aid concentrated in vacuo

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

Procedure: A suspension of 9,12-dioxa-1,3-diazadispiro[4.2.4.2]tetradecane-2,4-dione (6.33 g, 28.0 mmol) in HCl (6N) (28 mL, 168 mmol) and EtOH (66.0 mL) was stirred at RT for 18 hours. The mixture was partially evaporated (about ½ volume), cooled in an ice bath and brought to a pH of approximately 10. The aqueous layer was extracted with DCM (2×200 mL), and the aqueous layer concentrated. The residue was triturated with THF (2×100 mL), and solids were removed by filtration. The filtrate was evaporated to afford the title compound as a white solid. The mixture was partially evaporated (about ½ volume) cooled in an ice bath The aqueous layer was extracted with DCM (2×200 mL) the aqueous layer concentrated The residue was triturated with THF (2×100 mL), and solids were removed by filtration The filtrate was evaporated