Acetaldehyde → 1-Ethyl-7-[4-nitro-3-(propan-2-yloxy)phenyl]-1,7-diazaspiro[4.4]nonane

Participants

Reaction Steps

1.0 ml of acetaldehyde is added to a solution of 500 mg of 7-[4-nitro-3-(propan-2-yloxy)phenyl]-1,7-diazaspiro[4.4]nonane in 20 ml of 1,4-dichloroethane, cooled in a bath of ice-cold water. After 30 minutes, 1.12 g of sodium triacetoxyborohydride are added in small portions and the mixture is left to return to ambient temperature. The mixture is stirred at ambient temperature for 15 hours. 1 ml of acetaldehyde is then added and the mixture is stirred for 7 h. The mixture is concentrated to dryness under reduced pressure and the residue is diluted in 100 ml of dichloromethane. The organic phase is washed three times with 50 ml of water and the organic phase is dried over anhydrous magnesium sulfate, filtered and then concentrated to dryness under reduced pressure. The residue is purified by chromatography on silica gel, elution being carried out with a dichloromethane/isopropanol gradient: 100/0 to 50/50, and then by further chromatography on silica gel, elution being carried out with a dichloromethane/acetone gradient: 100/0 to 50/50, so as to obtain a yellow oil. This oil is taken up with ether, and the precipitate obtained is filtered off. The filtrate is concentrated to dryness under reduced pressure, so as to give 250 mg of 1-ethyl-7-[4-nitro-3-(propan-2-yloxy)phenyl]-1,7-diazaspiro[4.4]nonane in the form of a yellow oil.

Provenance & Evidence