Norstictic acid

Norstictic acid is a depsidone produced as a secondary metabolites in lichens.^[1] The compound contains both an aldehyde carbonyl group and an adjacent hydroxyl group in its molecular structure, which enables it to form complexes with certain metals. This property was demonstrated in studies of lichens growing on copper-rich substrates, where norstictic acid forms complexes with copper ions in the cortex (outer layer) of the lichen thallus, resulting in a distinctive green-yellow coloration. The formation of these copper-norstictic acid complexes appears to be selective, as evidenced by comparing it to the structurally similar stictic acid, which lacks the adjacent hydroxy group and does not form copper complexes. This metal-binding capability may have implications for both lichen taxonomy and the use of lichens as biological indicators of metal mineralization, though the formation of such complexes is not the only mechanism by which lichens can tolerate high metal concentrations in their environment.^[2]

Norstictic acid

Names
IUPAC name 5,13,17-Trihydroxy-7,12-dimethyl-9,15-dioxo-2,10,16-trioxatetracyclo[9.7.0.03,8.014,18]octadeca-1(11),3,5,7,12,14(18)-hexaene-4-carbaldehyde
Other names Bryopogonic acid, KBio3_001409
Identifiers
CAS Number	571-67-5 N
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL228281
ChemSpider	4528081
PubChem CID	5379540
CompTox Dashboard (EPA)	DTXSID30972564
InChI InChI=1S/C18H12O9/c1-5-3-8(20)7(4-19)14-9(5)16(22)26-13-6(2)12(21)10-11(15(13)25-14)18(24)27-17(10)23/h3-4,18,20-21,24H,1-2H3 Key: IEVVSJFLBYOUCJ-UHFFFAOYSA-N InChI=1/C18H12O9/c1-5-3-8(20)7(4-19)14-9(5)16(22)26-13-6(2)12(21)10-11(15(13)25-14)18(24)27-17(10)23/h3-4,18,20-21,24H,1-2H3 Key: IEVVSJFLBYOUCJ-UHFFFAOYAA
SMILES CC1=CC(=C(C2=C1C(=O)OC3=C(O2)C4=C(C(=C3C)O)C(=O)OC4O)C=O)O
Properties
Chemical formula	C18H12O9
Molar mass	372.285 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references