Synthesis of New Fused Pirano[4,3-b]pyridine Derivatives

A method was developed for the synthesis of pyrano[4,3- b ]thieno[3,2- e ]pyridine derivatives based on the reaction of 3-amino-7-ethyl-7-methyl-7,8-dihydro-5 H -pyrano[4,3- b ]thieno[3,2- e ]pyridine-2-carboxylic acid ethyl ester with chloroacetic acid chloride, triethyl orthoformate, hydrazine hydrate, and also phenyl chloroformate. The synthesis of various new representatives of pyrano[2″,3″:5′,6′]pyrido[3′,2′:4,5]thieno[3,2- d l-pyrimidine series was carried out.