Dimethyl Sulfoxide → HCID 13874706, compound

Participants

Reaction Steps

A solution of dimethyl sulfoxide (4.50 g, 57.6 mmol) in CH2Cl2 (24 mL) was added dropwise at −70° C. to a solution of oxalyl chloride (3.94 g, 31.0 mmol) in CH2Cl2 (72 mL), then after 15 min a solution of (4-hydroxy-butyl)-carbamic acid benzyl ester (4.95 g, 22.2 mmol) in CH2Cl2 (36 mL) was added dropwise. After 60 min triethylamine (11.2 g, 111 mmol) was added, then after 20 min the reaction mixture was allowed to reach RT over 2 h. The reaction mixture was washed with water, dried (MgSO4) and filtered to afford (4-oxo-butyl)-carbamic acid benzyl ester as CH2Cl2 solution. This was added at RT to a mixture of (S)-6-aza-spiro[2.5]octan-4-ol hydrochloride (3.63 g, 22.2 mmol), sodium triacetoxyborohydride (5.17 g, 24.4 mmol), AcOH (2.66 g, 44.3 mmol), and triethylamine (2.24 g, 22.2 mmol), then after 16 h the reaction mixture was washed with 2 M aq. sodium carbonate solution. The organic layer was washed with water, dried (MgSO4) and filtered, and evaporated. Chromatography (SiO2; CH2Cl2→CH2Cl2/MeOH/25% aq. ammonia solution 90:10:0.25) afforded the title compound (4.54 g, 62%). Colorless gum, MS: 435.3 (M+H)+.

Provenance & Evidence