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 temperature for 3.5 hours. 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 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 at room temperature for 14 hours. The resulting suspension was filtered on a Celite pad and the cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure and the residue was partitioned between an aqueous solution of sodium carbonate and ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and concentrated to give 0.680 (88%) of (5-chloro-1H-indol-3-yl)methanamine as a brown solid.

1. temperatureat reflux temperature for 3.5 hours
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 residue (crude oxime) was dissolved in glacial acetic acid (30 mL)
7. filtrationThe resulting suspension was filtered on a Celite pad
8. washthe cake was washed with ethyl acetate
9. concentrationThe filtrate was concentrated under reduced pressure
10. customthe residue was partitioned between an aqueous solution of sodium carbonate and ethyl acetate
11. dry with materialThe organic layer was dried over magnesium sulfate
12. filtrationfiltered
13. concentrationconcentrated

ORD record

ord-c76f795325af4d34873868b7423221f2

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09266832B2