Hydrochloric Acid → HCID 68158098, compound

A solution of (3aS,6aS)-rel-3a,4,6,6a-tetrahydro-furo[3,4-d]isoxazole-3-carboxylic acid ethyl ester (18.9 mmol) (intermediate IV-2) in ethanol (60 ml) was cooled to 5° C. Sodium borohydride (37.8 mmol) was added portionwise over a period of 15 minutes. During gas evolution the temperature was maintained between 5 and 10° C. Thereafter, the reaction mixture was stirred between 25 and 28° C. for 1 hour. For the workup, the reaction mixture was cooled in an ice bath and 3M hydrochloric acid (12 ml) was added dropwise. The mixture was allowed to warm to room temperature and was then treated with a solution sodium carbonate (2M; 10 ml). The suspension was concentrated at reduced pressure, the resulting solid was stirred in dichloromethane, then filtered, and the filtrate was concentrated at reduced pressure. The crude product was purified by chromatography on silica gel using a gradient of heptane and ethyl acetate=100:0 to 0:100 as the eluent. The (3aS,6aS)-rel-1-(3a,4,6,6a-tetrahydro-furo[3,4-d]isoxazol-3-yl)-methanol (2.06 g, 76% yield) was obtained as a light yellow oil. MS: m/z=144.0 [M+H]+.

1. temperatureDuring gas evolution the temperature was maintained between 5 and 10° C
2. temperatureFor the workup, the reaction mixture was cooled in an ice bath
3. concentrationThe suspension was concentrated at reduced pressure
4. stirringthe resulting solid was stirred in dichloromethane
5. filtrationfiltered
6. concentrationthe filtrate was concentrated at reduced pressure
7. customThe crude product was purified by chromatography on silica gel using a gradient of heptane and ethyl acetate=100:0 to 0:100 as the eluent

ORD record

ord-180c53623e624f1ba0d0a23436b3b370

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08404680B2