An efficient one-pot reaction of indoles, nitroacetate, and paraformaldehyde for the synthesis of tryptophan derivatives

An efficient method for the synthesis of tryptophan analogues has been developed via one-pot reaction of commercial available indoles, ethyl nitroacetate and paraformaldehyde in the presence of molecular sieves. The reaction provided tryptophan nitro-precursors in moderate to good yields, which were further converted to α-hydroxymethylated tryptophan derivatives catalyzed by DABCO in high yields.