Pyrans: Heterocycles of chemical and biological interest

Six-membered heterocyclic compounds containing oxyg en such as 2H-pyran and 4H-pyrans constitute an imp ortant class of biologically active natural and synthetic products, playing a fundamental role in bioorganic chemistry and continuing to attract interest. Pyrans and their analogues occupy prime position in Bioorganic chemistry due to their diverse applications. In this review, up to date information about the developments, explorationof new methodologies and varied biological activities of pyran analogues was discussed.