Chemistry of coumarins. Thermal reactions of 4‐chloro‐3‐coumarinyl N,N ‐dialkyldithiocarbamates and 3‐nitro‐4‐coumarinyl N ‐phenyldithiocarbamate

The thermal reactions of 4‐chloro‐3‐coumarinyl N,N ‐dialkyldithiocarbamates 2–4 and 3‐nitro‐4‐coumarinyl N ‐phenyldithiocarbamate, 9 , afforded the novel heterocyclic systems, e.g. bis‐6 H ‐1‐benzopyrano[4,3‐ b ]1,4]dithiin, 7 , and bis‐6 H ‐1‐benzopyrano[4,3‐ b ][1,4]thiazine, 14. A possible mechanism of the formation of the reaction products is discussed.