Dimethylformamide → Isoquinoline-5-carboxaldehyde

Temperature

-78 °C

To a solution of n-butyllithium (19.3 mL of 2.5M in hexanes, 48 mmol) in a mixture of ether (80 mL) and THF (80 mL) at −78° C. was added dropwise a solution of bromoisoquinoline (5.0 g, 24 mmol) in THF (10 mL). The reaction mixture was stirred at −78° C. under argon for 30 minutes. Following the general procedures described by Pearson, et al., in J. Heterocycl. Chem., Vol. 6 (2), pp. 243-245 (199), a solution of DMF (3.30 g, 45 mmol) in THF (10 mL) was cooled to −78° C. and quickly added to the isoquinolyllithium solution. The mixture was stirred at −78° C. for 15 minute. Ethanol (20 mL) was added followed by saturated NH4Cl solution. The resulting suspension was warmed to room temperature. The organic layer, combined with the ether extraction layer, was dried over Na2SO4. A pale yellow solid (2.4 g, 15 mmol, 64% yield) was obtained from chromatography (SiO2 Type-H, 50% EtOAc in hexanes) and recrystallization (ethanol): mp 114-116° C.;

1. stirringThe mixture was stirred at −78° C. for 15 minute
2. temperatureThe resulting suspension was warmed to room temperature
3. extractionThe organic layer, combined with the ether extraction layer
4. dry with materialwas dried over Na2SO4

ORD record

ord-3e5d05227a1448bb9b18bac65890476a

Source dataset

uspto-grants-2003_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06645975B1