Methylamine → (3-Chlorobenzo[b]thiophen-2-ylmethyl)methylamine

To 3-chloro-benzo[b]thiophene-2-carbaldehyde (1.9 g, 9.5 mmol) was added a solution of 2 M methylamine in methanol (32 mL) and the resulting mixture was stirred overnight at room temperature. The mixture was concentrated under reduced pressure and the residue taken up in ethanol (32 mL). The solution was cooled to 0° C., NaBH4 (0.54 g, 14 mmol) was added in one portion and stirring continued overnight. The mixture was concentrated under reduced pressure and the residue solvated in 1 M NaOH (200 mL). The mixture was extracted with diethyl ether (3×150 mL) and the combined organics were washed with brine (100 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a yellow oil. Purification by flash column chromatography (silica gel, hexanes/ethyl acetate 1:1) gave the title compound (1.62 g, 80%) as a pale yellow oil which crystallized under vacuum: 1H NMR (300 MHz, CDCl3) δ 7.70 (m, 2H), 7.45 (m, 2H), 4.08 (s, 2H), 2.51 (s, 3H).

1. concentrationThe mixture was concentrated under reduced pressure
2. temperatureThe solution was cooled to 0° C.
3. stirringstirring continued overnight
4. concentrationThe mixture was concentrated under reduced pressure
5. extractionThe mixture was extracted with diethyl ether (3×150 mL)
6. washthe combined organics were washed with brine (100 mL)
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customto give a yellow oil
11. customPurification by flash column chromatography (silica gel, hexanes/ethyl acetate 1:1)

ORD record

ord-78bf07c8b1644ba693b8b4cf939c9737

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07879872B2