Pyrones

thumb|right|75px|2-Pyrone thumb|right|75px|4-Pyrone Pyrones or pyranones are a class of heterocyclic chemical compounds. They contain an unsaturated six-membered ring, which has one oxygen atom and a carbonyl functional group. There are two isomers, denoted as 2-pyrone and 4-pyrone. The 2-pyrone (or α-pyrone) structure is a lactone and is found in nature as part of the coumarin ring system. The 4-pyrone (or γ-pyrone) structure is an ether–ketone found in some natural chemical compounds such as chromone, maltol and kojic acid.

thumb|Withaferin A thumb|Salpichrolid A thumb|Nicandrenon-1 thumb|Ixocarpalacton A Withanolides are a group of at least 300 naturally occurring steroids built on an ergostane skeleton. They occur as secondary metabolites primarily in genera of the Nightshade family, for example in the tomatillo.

chemical compound