Formaldehyde → 1-[4-(Diethylamino)but-2-yn-1-yl]pyrrolidin-2-one

Participants

Reaction Steps

1-(2-propynyl)-3-pyrrolidinone, prepared from propargyl bromide and the potassium salt of pyrrolidinone, is reacted with paraformaldehyde and diethylamine using cuprous chloride as catalyst to give 1-[4-(diethylamino)-2-butynyl]-2-pyrrolidinone. This compound is reacted with cyanogen bromide to give 1-(4-bromo-2-propynyl)-2-pyrrolidinone (BPP) which is then reacted with excess imidazole to give 1-[4-(1H-imidazol-1-yl)-2-butynyl]-2-pyrrolidinone (Compound 1, shown in Table 1). It was essential to avoid the use of strong bases in this reaction, because when BPP is reacted with the potassium salt of imidazole the allene is yielded as the major product.

Provenance & Evidence