Boron trifluoride etherate → 3-Bromo-7-tert-butoxy-1-nitronaphthalene

Temperature

-15 °C

To a stirred solution of 1-amino-2-bromo-6-tert-butoxy-4-nitronaphthalene, as described above in Step F, (2.40 g, 7.08 mmol) in CH2Cl2 (150 mL), at −15° C., was added BF3.OEt2 (1.35 mL, 10.6 mmol). To this mixture was added a solution of 90% tert-butyl nitrite (1.12 mL, 8.49 mmol) in CH2Cl2 (9 mL), dropwise. The reaction mixture was stirred at −15° C. for 1 hour, then 50 wt % H3PO2 (9.34 mL, 70.8 mmol) and CuO2 (50 mg, 0.349 mmol) were added and the resulting mixture was stirred vigorously at 0° C. for 40 min. The mixture was partitioned between saturated aqueous Na2CO3 (75 mL) and CH2Cl2 (150 mL). The aqueous layer was extracted further with CH2Cl2 (150 mL). The combined organic extracts were dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by flash column chromatography on silica, eluting with a gradient of hexane—0% to 8% diethyl ether to yield the titled compound.

1. stirringthe resulting mixture was stirred vigorously at 0° C. for 40 min
2. customThe mixture was partitioned between saturated aqueous Na2CO3 (75 mL) and CH2Cl2 (150 mL)
3. extractionThe aqueous layer was extracted further with CH2Cl2 (150 mL)
4. dry with materialThe combined organic extracts were dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe crude product was purified by flash column chromatography on silica
8. washeluting with a gradient of hexane—0% to 8% diethyl ether

ORD record

ord-85a27d8ac43541a9ad01e968c71ecc44

Source dataset

uspto-grants-2002_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06441017B1