A simple strategy for the synthesis of some 2-substituted melatonin
derivatives using p-anisidine as starting
material is reported. The key step is a chemoselective reduction
of a cyano group in the presence of an appropriate acid anhydride
by hydrogenation over Adams’ catalyst or with sodium borohydride
in the presence of catalytic amounts of anhydrous nickel(II) chloride.
The 2-substituted melatonin derivatives were obtained in six or
seven steps from inexpensive p-anisidine
in 9-13% overall yield.
indoles - melatonin derivatives - reductions - medicinal chemistry
