Hydrazinecarboxaldehyde → HCID 86700997, compound

Participants

Reaction Steps

1,1′-Carbonyldiimidazole (5.8 g, 36.2 mmol) was added to a 0° C. solution of (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylic acid (5.0 g, 18.1 mmol) in dry THF (200 mL). The reaction mixture was allowed to warm to rt then was stirred at rt for 3 hrs. Formohydrazide (5.4 g, 90.5 mmol) was added in one portion, and the reaction mixture was stirred for additional 3 hrs. The mixture was then diluted with saturated sodium chloride and extracted with EtOAc (3×). The combined organic layer was washed with saturated sodium chloride (2×), dried over Na2SO4, and concentrated to afford crude (2S,5R)-6-(benzyloxy)-N′-formyl-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carbohydrazide (˜11 g), which was directly used in the next step. ESI-MS (EI+, m/z): 319.1 [M+H]+. Step 2: To a −10° C. solution of (2S,5R)-6-(benzyloxy)-N′-formyl-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carbohydrazide (11 g) in dry DCM (200 mL) was added pyridine (28 mL), followed by dropwise addition of (CF3SO2)2O (28 mL). The reaction mixture was allowed to warm to rt and was stirred for 3 hrs. The reaction mixture was then cooled to −10° C. and quenched with sat. NaHCO3. The organic layer was separated and the aqueous layer was extracted with EtOAc (3×). The combined organic layer was dried over Na2SO4, concentrated and purified by silica gel column chromatography (gradient elution 1:3 to 2:1 EtOAc/hexanes) to give (2S,5R)-6-(benzyloxy)-2-(1,3,4-oxadiazol-2-yl)-1,6-diazabicyclo[3.2.1]octan-7-one (4.6 g, 86% for two steps) as a slightly yellow solid. ESI-MS (EI+, m/z): 301.0 [M+H]+. Step 3: To a solution of (2S,5R)-6-(benzyloxy)-2-(1,3,4-oxadiazol-2-yl)-1,6-diazabicyclo[3.2.1]octan-7-one (4.6 g, 15.3 mmol) in THF (150 mL) was added 10% Pd/C (1 g). The mixture was stirred under H2 atmosphere at rt for 3 hrs. The reaction mixture was then filtered and concentrated to afford the compound of Formula (I): (2S,5R)-6-hydroxy-2-(1,3,4-oxadiazol-2-yl)-1,6-diazabicyclo[3.2.1]octan-7-one (2.9 g, 91%). ESI-MS (EI+, m/z): 211.1 [M+H]+.

Provenance & Evidence