Hydrazinecarboxaldehyde → HCID 86700997, compound

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]+.

1. stirringthe reaction mixture was stirred for additional 3 hrs
2. extractionextracted with EtOAc (3×)
3. washThe combined organic layer was washed with saturated sodium chloride (2×)
4. dry with materialdried over Na2SO4
5. concentrationconcentrated
6. customto afford crude (2S,5R)-6-(benzyloxy)-N′-formyl-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carbohydrazide (˜11 g), which
7. temperatureto warm to rt
8. stirringwas stirred for 3 hrs
9. temperatureThe reaction mixture was then cooled to −10° C.
10. customquenched with sat. NaHCO3
11. customThe organic layer was separated
12. extractionthe aqueous layer was extracted with EtOAc (3×)
13. dry with materialThe combined organic layer was dried over Na2SO4
14. concentrationconcentrated
15. custompurified by silica gel column chromatography (gradient elution 1:3 to 2:1 EtOAc/hexanes)

ORD record

ord-fb8dd9dedabc40b0b7b32f0599e5a964

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09120796B2