Mucochloric acid

Mucochloric acid
Names
	IUPAC name (2Z)-2,3-Dichloro-4-oxobut-2-enoic acid
	Other names 2,3-Dichloromalealdehydic acid; α,β-Dichloro-β-formylacrylic acid;
Identifiers
CAS Number	87-56-9;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL1879926;
ChemSpider	2052308;
ECHA InfoCard	100.001.594
EC Number	201-752-4;
PubChem CID	2771871;
UNII	5I5877JHIW;
CompTox Dashboard (EPA)	DTXSID7020423 ;
	InChI InChI=1/C4H2Cl2O3/c5-2(1-7)3(6)4(8)9/h1H,(H,8,9)/b3-2- Key: LUMLZKVIXLWTCI-IHWYPQMZSA-N;
	SMILES O=CC(Cl)=C(Cl)C(O)=O;
Properties
Chemical formula	C4H2Cl2O3
Molar mass	168.96 g·mol−1
Melting point	124–128 °C (255–262 °F; 397–401 K)
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Corrosive, toxic
	GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H301, H314, H317, H341, H412
Precautionary statements	P203, P260, P264, P264+P265, P270, P272, P273, P280, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P318, P321, P330, P333+P317, P362+P364, P363, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Mucochloric acid is an organic compound with the formula C₄H₂Cl₂O₃. It consists of a dichlorinated alkene bearing aldehyde and carboxylic acid functional groups. It is the chlorinated analog of mucobromic acid and one of the known mucohalic acids. Mucochloric acid exists in equilibrium between open-chain and cyclic (furanone hemiacetal) forms, analogous to mucobromic acid. Mucochloric acid occurs as a chlorine disinfection byproduct in drinking water.^[2]

Synthesis

Mucochloric acid can be prepared by chlorination of furfural or related compounds such as furoic acid.^[3]

Applications

Due to its reactive chlorine atoms, double bond, and carbonyl groups, mucochloric acid serves as a versatile intermediate in organic synthesis, including for substituted furanones and other heterocycles.^[4]^[5]

Safety

Mucochloric acid is corrosive and toxic. It exhibits mutagenic and genotoxic activity.^[2]^[6]

References

^ "Mucochloric acid". ChemicalBook. Retrieved 2026-01-05.
^ ^a ^b Jansson, Kristian; Hyttinen, Juha M. T.; Niittykoski, Minna; Mäki-Paakkanen, Jorma (1995). "Mutagenicity in vitro of 3,4-dichloro-5-hydroxy-2( 5H )-furanone (Mucochloric acid), a chlorine disinfection by-product in drinking water". Environmental and Molecular Mutagenesis. 25 (4): 284–287. Bibcode:1995EnvMM..25..284J. doi:10.1002/em.2850250404. PMID 7607182.
^ US 2821553A, Andrew P. Dunlop, Edward Sherman, "Preparation of mucochloric acid", published 1958-01-28
^ Bellina, Fabio; Anselmi, Chiara; Martina, Francesca; Rossi, Renzo (2003). "Mucochloric Acid: A Useful Synthon for the Selective Synthesis of 4-Aryl-3-chloro-2(5 H )-furanones, ( Z )-4-Aryl-5-[1-(aryl)methylidene]-3-chloro-2(5 H )-furanones and 3,4-Diaryl-2(5 H )-furanones". European Journal of Organic Chemistry (12): 2290–2302. doi:10.1002/ejoc.200300097.
^ Kurbangalieva, A. R.; Devyatova, N. F.; Bogdanov, A. V.; Berdnikov, E. A.; Mannafov, T. G.; Krivolapov, D. B.; Litvinov, I. A.; Chmutova, G. A. (2007). "Synthesis of Novel Arylthio Derivatives of Mucochloric Acid". Phosphorus, Sulfur, and Silicon and the Related Elements. 182 (3): 607–630. doi:10.1080/10426500601015989.
^ Lalonde, Robert T.; Perakyla, Hannu; Cook, Gary P.; Dence, Carlton W. (1990). "Short Communication: Contribution of the 5-hydroxyl group to the mutagenicity of mucochloric acid". Environmental Toxicology and Chemistry. 9 (6): 687–691. Bibcode:1990EnvTC...9..687L. doi:10.1002/etc.5620090601.

[1] "Mucochloric acid". ChemicalBook. Retrieved 2026-01-05.

[Jansson-2] Jansson, Kristian; Hyttinen, Juha M. T.; Niittykoski, Minna; Mäki-Paakkanen, Jorma (1995). "Mutagenicity in vitro of 3,4-dichloro-5-hydroxy-2( 5H )-furanone (Mucochloric acid), a chlorine disinfection by-product in drinking water". Environmental and Molecular Mutagenesis. 25 (4): 284–287. Bibcode:1995EnvMM..25..284J. doi:10.1002/em.2850250404. PMID 7607182.

[patent-3] US 2821553A, Andrew P. Dunlop, Edward Sherman, "Preparation of mucochloric acid", published 1958-01-28

[4] Bellina, Fabio; Anselmi, Chiara; Martina, Francesca; Rossi, Renzo (2003). "Mucochloric Acid: A Useful Synthon for the Selective Synthesis of 4-Aryl-3-chloro-2(5 H )-furanones, ( Z )-4-Aryl-5-[1-(aryl)methylidene]-3-chloro-2(5 H )-furanones and 3,4-Diaryl-2(5 H )-furanones". European Journal of Organic Chemistry (12): 2290–2302. doi:10.1002/ejoc.200300097.

[5] Kurbangalieva, A. R.; Devyatova, N. F.; Bogdanov, A. V.; Berdnikov, E. A.; Mannafov, T. G.; Krivolapov, D. B.; Litvinov, I. A.; Chmutova, G. A. (2007). "Synthesis of Novel Arylthio Derivatives of Mucochloric Acid". Phosphorus, Sulfur, and Silicon and the Related Elements. 182 (3): 607–630. doi:10.1080/10426500601015989.

[6] Lalonde, Robert T.; Perakyla, Hannu; Cook, Gary P.; Dence, Carlton W. (1990). "Short Communication: Contribution of the 5-hydroxyl group to the mutagenicity of mucochloric acid". Environmental Toxicology and Chemistry. 9 (6): 687–691. Bibcode:1990EnvTC...9..687L. doi:10.1002/etc.5620090601.

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