A facile synthesis of novel 2-(4-oxochromen-3-yl) benzothiazolium bromides 4 and benzoxazolium bromide 5 using the one-pot condensation of substituted 4-oxochromene-3-carboxaldehydes 1 with 2-methylbenzothiazole (2a) or 2-methylbenzoxazole (2b) and benzyl bromide is described. The effects of benzothiazolium bromides 4 on the growth stimulation of the cucumber and retardant activity on corn seedlings were investigated. They inhibited growth of cucumber (root and hypocotyl) and shoots of corn at the range of 10 – 100 ppm and stimulated at 0.1 – 1 ppm concentrations.
Synthesis and plant growth activity of 2-(4-oxochromen-3-yl)benzothiazolium and -benzoxazolium bromides