Aconitic acid

Aconitic acid refers to organic compounds with the formula HO₂CCH₂C(CO₂H)=CHCO₂H. A white solid, it is classified as a tricarboxylic acid. The two isomers are cis-aconitic acid and trans-aconitic acid. The conjugate base of cis-aconitic acid, cis-aconitate is an intermediate in the isomerization of citrate to isocitrate in the citric acid cycle. It is acted upon by the enzyme aconitase.

Aconitic acid^[1]

cis-aconitic acid
trans-aconitic acid
Names
Preferred IUPAC name Prop-1-ene-1,2,3-tricarboxylic acid
Other names Achilleic acid; equisetic acid; citridinic acid; pyrocitric acid; achilleaic acid; acinitic acid
Identifiers
CAS Number	499-12-7 Y 585-84-2 (cis) Y 4023-65-8 (trans) Y
ChemSpider	303 (cis) N
ECHA InfoCard	100.007.162
PubChem CID	309 (cis and trans)
UNII	93371T1BXP Y OF5471ZHRR (cis) Y 7DB37960CW (trans) Y
CompTox Dashboard (EPA)	DTXSID9060102
InChI InChI=1S/C4H8/c1-3-4-2/h3-4H,1-2H3 Y Key: GTZCVFVGUGFEME-UHFFFAOYSA-N Y InChI=1/C6H6O6/c7-4(8)1-3(6(11)12)2-5(9)10/h1H,2H2,(H,7,8)(H,9,10)(H,11,12) Key: GTZCVFVGUGFEME-UHFFFAOYAL
Properties
Chemical formula	C6H6O6
Molar mass	174.108 g·mol−1
Appearance	Colorless crystals
Melting point	190 °C (374 °F; 463 K) (decomposes) (mixed isomers), 173 °C (cis and trans isomers)
Acidity (pKa)	2.80, 4.46 (trans isomer)[2] 2.78, 4.41, 6.21 (cis isomer)[3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Aconitic acid can be synthesized by dehydration of citric acid using sulfuric acid:^[4]

(HO₂CCH₂)₂C(OH)CO₂H → HO₂CCH=C(CO₂H)CH₂CO₂H + H₂O

A mixture of isomers is generated in this way.

Aconitic acid was originally isolated from Aconitum napellus by Swiss chemist and apothecary Jacques Peschier in 1820.^[5][6] It was first prepared by thermal dehydration.^[7]

Like the conjugate bases of other polycarboxylic acid, acotinic acid forms a variety of coordination complexes. One example is the coordination polymer [Zn₃(C₆H₃O₆)₂(H₂O)₆]_n.^[8]