Hydroxyamine hydrochloride → (5-Chloro-1H-indol-3-yl)methanamine

A solution of 5-chloro-1H-indole-3-carbaldehyde (0.690 g; 3.76 mmol), hydroxylamine hydrochloride (0.366 g; 5.27 mmol) and sodium acetate (0.463 g; 5.65 mmol) in ethanol (10 mL) was stirred at reflux for 3.5 h. The reaction mixture was concentrated under reduced pressure and the residue was partitioned between ethyl acetate and brine and extracted with ethyl acetate. The solvent was evaporated and the resulting residue (crude oxime) was dissolved in glacial acetic acid (30 mL). Zinc dust (1.48 g; 22.59 mmol) was added to the solution, and the mixture was stirred overnight at room temperature. The suspension was filtered through Celite, the cake was washed with ethyl acetate, and the organic solution was concentrated under reduced pressure. An aqueous solution of sodium carbonate was added to the residue and the resulting mixture was extracted with ethyl acetate. The organic extracts were dried over magnesium sulfate, filtered, and concentrated to afford the (5-chloro-1H-indol-3-yl)methanamine as a brown solid, which was used without further purification in the next step.

1. temperatureat reflux for 3.5 h
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. customthe residue was partitioned between ethyl acetate and brine
4. extractionextracted with ethyl acetate
5. customThe solvent was evaporated
6. dissolutionthe resulting residue (crude oxime) was dissolved in glacial acetic acid (30 mL)
7. filtrationThe suspension was filtered through Celite
8. washthe cake was washed with ethyl acetate
9. concentrationthe organic solution was concentrated under reduced pressure
10. additionAn aqueous solution of sodium carbonate was added to the residue
11. extractionthe resulting mixture was extracted with ethyl acetate
12. dry with materialThe organic extracts were dried over magnesium sulfate
13. filtrationfiltered
14. concentrationconcentrated

ORD record

ord-101cf28be69643698713358d516253f7

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09434722B2