Methanol → Isoquinolin-3-ylmethanol

Temperature

75 °C

To a stirred solution of isoquinoline-3-carboxylic acid (0.3179 g, 1.84 mmol) in dry THF (10 mL) at room temperature was added BH3—THF (1.0 M, 7.5 mL, 7.5 mmol). The mixture was stirred for 17 hrs, dry CH3OH (10 mL) was added, and the reaction was heated to 75° C. with stirring for a further 24 hrs. The mixture was concentrated and the residue was treated with dry CH3OH (3×10 mL), removing the solvent by evaporation each time. The crude product was purified by column chromatography (12 g silica gel, 19:1 CH2Cl2:CH3OH) to give 0.0359 g of 3-(hydroxymethyl)isoquinoline as a white film. The solid was dissolved in dry CH2Cl2 (5 mL) and treated with MnO2 (˜85%, 0.2978 g, 2.91 mmol) with stirring for 19 hrs then filtered through celite. Concentration of the filtrate afforded 0.0252 g (9%) of isoquinoline-3-carboxaldehyde as yellow oil. 1H NMR (CDCl3) d 7.73-7.82 (m, 2H), 7.97-8.07 (m, 2H), 8.37 (s, 1H), 9.36 (s, 1H), 10.25 (s, 1H).

1. stirringwith stirring for a further 24 hrs
2. concentrationThe mixture was concentrated
3. additionthe residue was treated with dry CH3OH (3×10 mL)
4. customremoving the solvent
5. customby evaporation each time
6. customThe crude product was purified by column chromatography (12 g silica gel, 19:1 CH2Cl2:CH3OH)

ORD record

ord-77f6f5c522de43759e4eb30589cdde01

Source dataset

uspto-grants-2008_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07396840B2