Mucic acid

Mucic acid, C₆H₁₀O₈ or HOOC-(CHOH)₄-COOH (galactaric acid or meso-galactaric acid) is an aldaric acid obtained by nitric acid oxidation of galactose or galactose-containing compounds such as lactose, dulcite, quercite, and most varieties of gum.^[2]

Mucic acid

Names
IUPAC name meso-Galactaric acid[1]
Systematic IUPAC name (2S,3R,4S,5R)-2,3,4,5-Tetrahydroxyhexanedioic acid
Other names Galactaric acid; Galactosaccharic acid
Identifiers
CAS Number	526-99-8 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL1232958 N
ChemSpider	2301286 N
ECHA InfoCard	100.007.641
PubChem CID	3037582
UNII	E149J5OTIF Y
CompTox Dashboard (EPA)	DTXSID7048740
InChI InChI=1S/C6H10O8/c7-1(3(9)5(11)12)2(8)4(10)6(13)14/h1-4,7-10H,(H,11,12)(H,13,14)/t1-,2+,3+,4- N Key: DSLZVSRJTYRBFB-DUHBMQHGSA-N N InChI=1/C6H10O8/c7-1(3(9)5(11)12)2(8)4(10)6(13)14/h1-4,7-10H,(H,11,12)(H,13,14)/t1-,2+,3+,4- Key: DSLZVSRJTYRBFB-DUHBMQHGBT
SMILES [C@@H]([C@@H]([C@H](C(=O)O)O)O)([C@@H](C(=O)O)O)O
Properties
Chemical formula	C6H10O8
Molar mass	210.138 g·mol−1
Melting point	230 °C (446 °F; 503 K)
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

Properties

Mucic acid forms a crystalline powder, which melts at 210–230 °C.^[3] It is insoluble in alcohol, and nearly insoluble in cold water.^[2] Due to the symmetry in the molecule, it is optically inactive even though it has chiral carbon atoms (i.e., it is a meso compound).

Reactions

When heated with pyridine to 140 °C, it is converted into allomucic acid.^[2][4] When digested with fuming hydrochloric acid for some time it is converted into αα′ furfural dicarboxylic acid while on heating with barium sulfide it is transformed into α-thiophene carboxylic acid.^[2] The ammonium salt yields on dry distillation carbon dioxide, ammonia, pyrrol and other substances.^[2] The acid when fused with caustic alkalis yields oxalic acid.^[2]

With potassium bisulfate mucic acid forms 3-hydroxy-2-pyrone by dehydration and decarboxylation.

Reaction of mucic acid to 3-hydroxy-2-pyrone with a) potassium bisulfate 160 °C / 4 hrs. b) hydrochloric acid to pH = 7

Use

Mucic acid can be used to replace tartaric acid in self-raising flour or fizzies.

It has been used as a precursor of adipic acid in the way to nylon by a rhenium-catalyzed deoxydehydration reaction.^[5]

It has been used as a precursor of Taxol in Nicolaou Taxol total synthesis (1994).

See also

• Muconic acid