(Diethylamino)sulfur trifluoride → tert-butyl 8-bromo-4-fluoro-3,4-dihydroisoquinoline-2(1H)-carboxylate

To a flask containing tert-butyl 8-bromo-4-hydroxy-3,4-dihydroisoquinoline-2(1H)-carboxylate (24-4) (622 mg, 1.895 mmol) was added anhydrous DCM (10 ml). The reaction mixture was then capped & cooled to −78 C (dry ice/acetone bath) while stirring under N2. Then added DAST (1.4 ml, 10.60 mmol) at −78 C. The reaction mixture was then stirred at −78 C. Followed by LC/MS. After 5 minutes at −78 C the reaction was quenched by dropwise addition of a saturated solution of NaHCO3 in water at −78 C (with a vent needle), then permitted to warm to room temperature, then the reaction mixture was suspended in EtOAc, washed with saturated NaHCO3, then H2O, then brine; organics dried over Na2SO4, filtered & concentrated to yield. Purification by silica gel chromatography (0-15% EtOAc/Hex; 40 g ISCO); desired fractions concentrated to yield tert-butyl 8-bromo-4-fluoro-3,4-dihydroisoquinoline-2(1H)-carboxylate (24-5).

1. customThe reaction mixture was then capped
2. stirringThe reaction mixture was then stirred at −78 C
3. customAfter 5 minutes at −78 C the reaction was quenched by dropwise addition of a saturated solution of NaHCO3 in water at −78 C (with a vent needle),
4. washwashed with saturated NaHCO3
5. dry with materialorganics dried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customto yield
9. customPurification by silica gel chromatography (0-15% EtOAc/Hex; 40 g ISCO)
10. concentrationdesired fractions concentrated

ORD record

ord-23d9594f8974438dbf35216b738c8476

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09273040B2