title: Chromone
text: # Chromone
  
  Chromone (or 1,4-benzopyrone) is a derivative of benzopyran with a substituted keto group on the pyran ring. It is an isomer of coumarin.
  
  Derivatives of chromone are collectively known as chromones. Most, though not all, chromones are also phenylpropanoids.
  
  ## Examples
  
  * 6,7-dimethoxy-2,3-dihydrochromone has been isolated from Sarcolobus globosus.
  * Eucryphin, a chromone rhamnoside, can be isolated from the bark of Eucryphia cordifolia.
  * Cromolyn (disodium cromoglicate) was found to inhibit antigen challenge as well as stress induced symptoms. Cromoglicate is used as a mast cell stabilizer in allergic rhinitis, asthma and allergic conjunctivitis.
  * Nedocromil sodium was found to have a somewhat longer half-life than cromolyn; however, production was discontinued in the US in 2008.
  * Xanthone with a second aromatic ring.
  