The one-pot synthesis and fluorimetric study of 3-(2′-benzothiazolyl)coumarins

A novel, piperidene-catalysed, one-pot synthesis of 3-(2′-benzothiazolyl)coumarins was undertaken, starting from salicylaldehydes, ethyl cyanoacetate and o-aminobenzenethiols in ethanol. Salicylaldehydes with electron-donating group gave optimum yields. The novel method is characterized by mild reaction conditions, simple procedure and low waste. All compounds were fluorescent in solution emitting either green light (490 nm) or blue light (440–460 nm). Two typical fluorescence peaks were found in the three-dimensional fluorescence spectra.