2H- und 4H-thiopyrane—eigenschaften, synthesen und reaktionen

摘要: Abstract This review presents properties, syntheses, and reactions of 2H- 4H-thiopyrans, either compounds exhibiting low thermal stability owing to their “non-aromatic” electronic structure or stabilized derivatives with electron-withdrawing group respectively, on an exo-methylene exo-allylidene in 2- 4-position. Such can be drawn canonic formulas corresponding donor acceptor systems charge transfer complexes. After earlier investigations the pyran-pyrylium ring system sulfur analogues have found increasing interest during last twenty-five years. Some these are now technical scientific as electric conductors, dyestuffs, intermediates for dyes long wave absorption maxima fluorescent respectively. Several been investigated biological activity; interesting this connection fluoro substituted derivatives. In compilations characteristic spectroscopic ...