3-Phenylpropanal and citral in the multicomponent synthesis of novel thiopyrano[2,3-d]thiazoles

A 3-phenylpropanal and citral were studied in the multicomponent reaction with the isorhodanine and maleimides (EDDA catalyst) with the aim of the novel thiopyrano[2,3-d]thiazoles synthesis. 3-Phenylpropanal reacts with the selective formation of the thiopyrano[2,3-d]thiazoles whereas citral led to the mixture of two products and Michael adducts are major. The one-pot/two-steps protocol was proposed for citral transformation to the target thiopyrano[2,3-d]thiazoles. The structures and stereochemistry of newly synthesized compounds were studied by spectral and X-ray data.