Formaldehyde → (S)-1-[4-diethylamino-2-butynyl]-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-pyrrolidinone

Participants

Reaction Steps

A mixture of 3.0 g of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1-propargyl-2-pyrrolidinone, 0.9 g of paraformaldehyde, 2.5 ml of diethylamine, 3.5 ml of acetic acid and 0.050 g of cuprous chloride is stirred at room temperature for 15 minutes, followed by heating at reflux temperature for 30 minutes. The reaction is cooled, Concentrated in vacuo, made basic (pH 10) with ammonium hydroxide and partitioned between methylene chloride and water. The layers are separated, the aqueous layer reextracted and the methylene chloride extracts are combined. The organic solution is dried and concentrated in vacuo with 100 ml of toluene as co-solvent. The residue is purified by chromatography (alumina, activity grade 2.5, 1-5% methyl alcohol/methylene chloride) to give 3.0 g of (S)-1-[4-(diethylamino)-2-butynyl]-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-pyrrolidinone as a yellow oil. [α]D26° =-56 (methylene chloride).

Provenance & Evidence