Hydrochloric Acid → Tert-butyl (6'-amino-2',2'-dimethyldispiro[1,3-oxazole-4,4'-chromene-3',3''-oxetan]-2-yl)carbamate

Temperature

100 °C

Under argon atmosphere, to a mixture of di-tert-butyl (6′-bromo-2′,2′-dimethyldispiro[1,3-oxazole-4,4′-chromene-3′,3″-oxetan]-2-yl)imidodicarbonate (1.00 g, 1.81 mmol), bis(dibenzylideneacetone)palladium (0) (104 mg, 0.181 mmol) and tri-tert-butylphosphonium tetrafluoroborate (53.5 mg, 0.181 mmol) was added lithium bis(trimethylsilyl)amide (1.0 M in toluene, 9.03 mL, 9.03 mmol) at ambient temperature. After stirring for 1 hour at 100° C., the reaction mixture was cooled down to ambient temperature. To the mixture were added 1.0 M hydrochloric acid (9.0 mL) and MeOH (9.0 mL) and the mixture was stirred for 30 minutes at ambient temperature. After extraction of the mixture with CHCl3, the organic layer was dried over Na2SO4 and filtered. The filtrate was concentrated at reduced pressure and the residue was purified by column chromatography on silica gel (hexane-EtOAc, a linear gradient of EtOAc from 0 to 90%) to give tert-butyl (6′-amino-2′,2′-dimethyldispiro[1,3-oxazole-4,4′-chromene-3′,3″-oxetan]-2-yl)carbamate (616 mg).

1. temperaturethe reaction mixture was cooled down to ambient temperature
2. stirringthe mixture was stirred for 30 minutes at ambient temperature
3. extractionAfter extraction of the mixture with CHCl3
4. dry with materialthe organic layer was dried over Na2SO4
5. filtrationfiltered
6. concentrationThe filtrate was concentrated at reduced pressure
7. customthe residue was purified by column chromatography on silica gel (hexane-EtOAc

ORD record

ord-018297ce33cd4096b454af9f538ad4c9

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08975415B2