Synthesis and nucleophilic dearomatization of highly electrophilic [1,2,5]selenadiazolo[3,4-b]pyridines

A New Efficient Method for the Synthesis of Fused [1,2,5]Thiadiazoles and Their Dearomatization with C‐Nucleophiles

“…Recently we have found that π‐deficient azolo[b]pyridines, in particular, bearing electron‐withdrawing groups, underwent dearomatization by the reactions with nucleophilic reagents and formation of azolo‐fused 1,4‐dihydropyridines [16–20] . The most π‐deficient azolo[ b ]pyridines synthesized in this work (compounds 2 a , b ) reacted with number of neutral carbon nucleophiles such as CH‐acids, indoles, pyrrole and phloroglucinol to give 1,4‐adducts 3 a – k , Scheme 4.…”

“…Recently we have found that π-deficient azolo[b]pyridines, in particular, bearing electron-withdrawing groups, underwent dearomatization by the reactions with nucleophilic reagents and formation of azolo-fused 1,4-dihydropyridines. [16][17][18][19][20] The most π-deficient azolo[b]pyridines synthesized in this work (compounds 2 a, b) reacted with number of neutral carbon nucleophiles such as CH-acids, indoles, pyrrole and phloroglucinol to give 1,4-adducts 3 a-k, Scheme 4. In general, reactions proceed smoothly at room temperature with no added base, however, the reaction time depends on the nature of a nucleophile and substituent R in compounds 2 a, b.…”