Lithium hexamethyldisilazane → tert-butyl [(4'R)-6'-amino-2',2'-dimethyldispiro[cyclopropane-1,3'-chromene-4',4''-[1,3]oxazol]-2''-yl]carbamate

Temperatur

60 °C

To a mixture of di-tert-butyl[(4′R)-6′-bromo-2′,2′-dimethyldispiro[cyclopropane-1,3′-chromene-4′,4″-[1,3]oxazol]-2″-yl]imidodicarbonate (1.98 g, 3.68 mmol), bis(dibenzylideneacetone)palladium(0) (212 mg, 0.369 mmol), and tri-tert-butylphosphonium tetrafluoroborate (108 mg, 0.371 mmol) was added lithium bis(trimethylsilyl)amide (1M solution in toluene, 18 ml, 18 mmol) at room temperature under argon atmosphere. The mixture was stirred at 60° C. for 2 hours and then quenched with saturated aqueous ammonium chloride. The mixture was extracted with chloroform. The organic layer was dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=100:0-50:50-0:100) to afford tert-butyl[(4′R)-6′-amino-2′,2′-dimethyldispiro[cyclopropane-1,3′-chromene-4′,4″-[1,3]oxazol]-2″-yl]carbamate (1.37 g).

1. customquenched with saturated aqueous ammonium chloride
2. extractionThe mixture was extracted with chloroform
3. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
4. concentrationconcentrated in vacuo
5. customThe residue was purified by silica gel column chromatography (hexane/ethyl acetate=100:0-50:50-0:100)

ORD-Eintrag

ord-f236d44accf743bc8d9743bc40ea7339

Quelldatensatz

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09242973B2