Hydrochloric Acid → 6-Aminopyridine-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1 g of 6-aminopyridine-3-carbonitrile in 20 mL of toluene cooled to −78° C. are added dropwise 15 mL of a 1.2 M solution of diisobutylaluminum hydride in toluene. The reaction medium is stirred for 30 minutes at −78° C. and is then allowed to warm slowly to 20° C. After cooling again to −78° C., 6 mL of water are added slowly and the resulting mixture is stirred for 1 hour at −78° C. The reaction medium is stirred for 16 hours at 20° C., treated with 20 mL of 2.5 N hydrochloric acid, stirred for 20 minutes, basified by addition of concentrated sodium hydroxide and extracted three times with 100 mL of dichloromethane. The combined organic phases are dried and concentrated to dryness under reduced pressure. The residue is taken up in 40 mL of ethyl acetate and 40 mL of saturated sodium bisulfite solution. The aqueous phase is washed twice with 40 mL of ethyl acetate, basified to about pH 14 by addition of concentrated sodium hydroxide, and extracted three times with 50 mL of dichloromethane. The combined organic phases are dried and concentrated to dryness under reduced pressure to give 200 mg of crude 6-aminopyridine-3-carboxaldehyde in the form of a yellow powder, which is used without further purification.

Provenance & Evidence