Umbellic acid

Umbellic acid

Chemical structure of umbellic acid
Names
IUPAC name (E)-3-(2,4-dihydroxyphenyl)prop-2-enoic acid
Other names 2,4-Dihydroxycinnamic acid (E)-2,4-Dihydroxycinnamic acid (2E)-3-(2,4-Dihydroxyphenyl)acrylic acid
Identifiers
CAS Number	614-86-8
ChemSpider	393925
Jmol 3D model	Interactive image
PubChem	446611
InChI InChI=1S/C9H8O4/c10-7-3-1-6(8(11)5-7)2-4-9(12)13/h1-5,10-11H,(H,12,13)/b4-2+ Key: HGEFWFBFQKWVMY-DUXPYHPUSA-N
SMILES C1=CC(=C(C=C1O)O)C=CC(=O)O
Properties
Chemical formula	C9H8O4
Molar mass	180.16 g·mol−1
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Umbellic acid (2,4-dihydroxycinnamic acid) is a hydroxycinnamic acid. It is an isomer of caffeic acid.

It is a precursor in the umbelliferone biosynthesis pathway. Umbelliferone is a phenylpropanoid and as such is synthesized from L-phenylalanine, which in turn is produced via the shikimate pathway. Phenylalanine is lysated into cinnamic acid, followed by hydroxylation by cinnamate 4-hydroxylase to yield 4-coumaric acid. The 4-coumaric acid is again hydroxylated by cinnamate/coumarate 2-hydroxylase to yield 2,4-dihydroxy-cinnamic acid followed by a bond rotation of the unsaturated bond adjacent to the carboxylic acid group. Finally an intramolecular attack from the hydroxyl group of C2' to the carboxylic acid group closes the ring and forms the lactone umbelliferone.

 $\xrightarrow{PAL}$  $\xrightarrow{C4H}$  $\xrightarrow{C2H}$ 2,4-Dihydroxycinnamic acid $\longrightarrow$ Umbelliferone

The enzyme 4-hydroxycinnamate decarboxylase, induced in bacteria species such as Klebsiella oxytoca, works also with p-coumaric acid analogs such as E-2,4-dihydroxycinnamic acid.

External links

The dictionary definition of umbellic acid at Wiktionary