# DCMU

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Not to be confused with the mercurial diuretic [Diurone](/source/Diurone). For the DC comics Movie Universe, see [DC Extended Universe](/source/DC_Extended_Universe).

DCMU Names Preferred IUPAC name N′-(3,4-Dichlorophenyl)-N,N-dimethylurea Other names 3-(3,4-Dichlorophenyl)-1,1-dimethylurea, Karmex, Diuron, Direx Identifiers CAS Number 330-54-1 Y 3D model (JSmol) Interactive image ChEBI CHEBI:116509 Y ChEMBL ChEMBL278489 Y ChemSpider 3008 Y ECHA InfoCard 100.005.778 EC Number 206-354-4 KEGG C18428 Y PubChem CID 3120 RTECS number YS8925000 UNII 9I3SDS92WY UN number 3077, 2767 CompTox Dashboard (EPA) DTXSID0020446 InChI InChI=1S/C9H10Cl2N2O/c1-13(2)9(14)12-6-3-4-7(10)8(11)5-6/h3-5H,1-2H3,(H,12,14) Y Key: XMTQQYYKAHVGBJ-UHFFFAOYSA-N Y SMILES Clc1ccc(NC(=O)N(C)C)cc1Cl Properties Chemical formula C9H10Cl2N2O Molar mass 233.09 g·mol−1 Appearance white crystalline solid[1] Density 1.48 g/cm3 Melting point 158 °C (316 °F; 431 K) Boiling point 180 °C (356 °F; 453 K) Solubility in water 42 mg/L Vapor pressure 0.000000002 mmHg (20°C)[1] Hazards GHS labelling: Pictograms Signal word Warning Hazard statements H302, H351, H373, H410 Precautionary statements P201, P202, P260, P264, P270, P273, P281, P301+P312, P308+P313, P314, P330, P391, P405, P501 Flash point noncombustible[1] NIOSH (US health exposure limits): PEL (Permissible) none[1] REL (Recommended) TWA 10 mg/m3[1] IDLH (Immediate danger) N.D.[1] Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

**DCMU** (**3-(3,4-dichlorophenyl)-1,1-dimethylurea**) is an [algicide](/source/Algicide) and [herbicide](/source/Herbicide) of the aryl [urea](/source/Ureas) class that inhibits [photosynthesis](/source/Photosynthesis). It was introduced by [Bayer](/source/Bayer) in 1954 under the trade name of **Diuron**.

## History

In 1952, chemists at [E. I. du Pont de Nemours and Company](/source/DuPont_(1802%E2%80%932017)) patented a series of [aryl](/source/Aryl) [urea](/source/Urea) derivatives as [herbicides](/source/Herbicides). Several compounds covered by this patent were commercialized as herbicides: [chlortoluron](/source/Chlortoluron) (3-chloro-4-methylphenyl) and DCMU, the (3,4-dichlorophenyl) example.[2][3] Subsequently, over thirty related urea [analogs](/source/Analogue_(chemistry)) with the same mechanism of action reached the market worldwide.[4]

## Synthesis

As described in the du Pont patent, the starting material is 3,4-dichloro[aniline](/source/Aniline), which is treated with [phosgene](/source/Phosgene) to form a [isocyanate](/source/Isocyanate) derivative. This is subsequently reacted with [dimethylamine](/source/Dimethylamine) to give the final product.[2]

- Aryl-NH2 + COCl2 → Aryl-NCO

- Aryl-NCO + NH(CH3)2 → Aryl-NHCON(CH3)2

## Mechanism of action

DCMU is a very specific and sensitive inhibitor of photosynthesis. It blocks the QB [plastoquinone](/source/Plastoquinone) binding site of [photosystem II](/source/Photosystem_II), disallowing the electron flow from photosystem II to plastoquinone.[5] This interrupts the [photosynthetic electron transport chain](/source/Photosynthetic_electron_transport_chain) in photosynthesis and thus reduces the ability of the plant to turn light energy into chemical energy ([ATP](/source/Adenosine_triphosphate) and [reductant potential](/source/Reductant)).

DCMU only blocks electron flow from photosystem II, it has no effect on photosystem I or other reactions in photosynthesis, such as light absorption or carbon fixation in the [Calvin cycle](/source/Calvin_cycle).[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

However, because it blocks electrons produced from water oxidation in [PS II](/source/PS_II) from entering the plastoquinone pool, "linear" photosynthesis is effectively shut down, as there are no available electrons to exit the photosynthetic electron flow cycle for reduction of [NADP+](/source/NADP) to NADPH. In fact, it was found that DCMU not only does not inhibit the [cyclic photosynthetic pathway](/source/Photophosphorylation#Cyclic_photophosphorylation), but, under certain circumstances, actually stimulates it.[6][7]

Because of these effects, DCMU is often used to study energy flow in [photosynthesis](/source/Photosynthesis).

## Toxicity

DCMU (Diuron) has been characterized as a known/likely human carcinogen based on animal testing.[8][9]

## References

1. ^ [***a***](#cite_ref-PGCH_1-0) [***b***](#cite_ref-PGCH_1-1) [***c***](#cite_ref-PGCH_1-2) [***d***](#cite_ref-PGCH_1-3) [***e***](#cite_ref-PGCH_1-4) [***f***](#cite_ref-PGCH_1-5) NIOSH Pocket Guide to Chemical Hazards. ["#0247"](https://www.cdc.gov/niosh/npg/npgd0247.html). [National Institute for Occupational Safety and Health](/source/National_Institute_for_Occupational_Safety_and_Health) (NIOSH).

1. ^ [***a***](#cite_ref-Todd_2-0) [***b***](#cite_ref-Todd_2-1) [US patent 2655445](https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US2655445), Todd C.W., "3-(Halophenyl)-1-methyl-1-(methyl or ethyl) ureas and herbicidal compositions and methods employing same", issued 1953-10-13, assigned to E. I. du Pont de Nemours & Co.

1. **[^](#cite_ref-Liu_3-0)** Liu, Jing (2010). "Phenylurea Herbicides". *Hayes' Handbook of Pesticide Toxicology*. pp. 1725–1731. [doi](/source/Doi_(identifier)):[10.1016/B978-0-12-374367-1.00080-X](https://doi.org/10.1016%2FB978-0-12-374367-1.00080-X). [ISBN](/source/ISBN_(identifier)) [9780123743671](https://en.wikipedia.org/wiki/Special:BookSources/9780123743671).

1. **[^](#cite_ref-4)** ["Urea herbicides"](http://www.alanwood.net/pesticides/class_herbicides.html#urea_herbicides). *alanwood.net*. Retrieved 2021-03-26.

1. **[^](#cite_ref-5)** Metz, J; Pakrasi, H; Seibert, M; Arntzer, C (1986). ["Evidence for a dual function of the herbicide-binding D1 protein in photosystem II"](https://doi.org/10.1016%2F0014-5793%2886%2980911-5). *FEBS Letters*. **205** (2): 269. [Bibcode](/source/Bibcode_(identifier)):[1986FEBSL.205..269M](https://ui.adsabs.harvard.edu/abs/1986FEBSL.205..269M). [doi](/source/Doi_(identifier)):[10.1016/0014-5793(86)80911-5](https://doi.org/10.1016%2F0014-5793%2886%2980911-5). [S2CID](/source/S2CID_(identifier)) [84205263](https://api.semanticscholar.org/CorpusID:84205263).

1. **[^](#cite_ref-6)** HUBER, S.C. EDWARDS, G.E. (1976), Studies on the Pathway of Cyclic Electron Flow in Mesophyll Chloroplasts of a C4 Plant, Biochimica et Biophysica Acta (BBA) - Bioenergetics, Volume 449, Issue 3, 6 December 1976, Pages 420-433, [doi](/source/Doi_(identifier)):[10.1016/0005-2728(76)90153-5](https://doi.org/10.1016%2F0005-2728%2876%2990153-5)

1. **[^](#cite_ref-7)** Hosler, J. P.; Yocum, C. F. (April 1987). ["Regulation of Cyclic Photophosphorylation during Ferredoxin-Mediated Electron Transport : Effect of DCMU and the NADPH/NADP Ratio"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1056483). *Plant Physiol*. **83** (4): 965–9. [Bibcode](/source/Bibcode_(identifier)):[1987PlanP..83..965H](https://ui.adsabs.harvard.edu/abs/1987PlanP..83..965H). [doi](/source/Doi_(identifier)):[10.1104/pp.83.4.965](https://doi.org/10.1104%2Fpp.83.4.965). [PMC](/source/PMC_(identifier)) [1056483](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1056483). [PMID](/source/PMID_(identifier)) [16665372](https://pubmed.ncbi.nlm.nih.gov/16665372).

1. **[^](#cite_ref-8)** ["Diuron"](https://pubchem.ncbi.nlm.nih.gov/source/hsdb/382). *National Center for Biotechnology Information*. United States National Library of Medicine. Retrieved 9 November 2021.

1. **[^](#cite_ref-9)** Linda, Taylor; Esther, Rinde (1997-05-08). [*Carcinogenicity Peer Review of Diuron*](https://www3.epa.gov/pesticides/chem_search/cleared_reviews/csr_PC-035505_8-May-97_042.pdf) (PDF) (Memorandum). Washington, D.C.: United States Environmental Protection Agency. 20460.

v t e Pest control: herbicides Anilides/anilines acetochlor alachlor asulam benfluralin butachlor diethatyl diflufenican dimethenamid flamprop metazachlor metolachlor oryzalin pendimethalin pretilachlor propachlor propanil trifluralin Aromatic acids aminopyralid chloramben clopyralid dicamba picloram pyrithiobac quinclorac quinmerac Arsenicals cacodylic acid copper arsenate DSMA MSMA HPPD inhbitors flurochloridone isoxaflutole leptospermone mesotrione nitisinone sethoxydim sulcotrione Nitriles DCBN bromoxynil ioxynil Organophosphorus bensulide bialaphos ethephon fosamine glufosinate glyphosate piperophos Phenoxy Auxins 2,4-D 2,4-DB dichlorprop fenoprop MCPA MCPB mecoprop 2,4,5-T ACCase inhibitors FOP herbicides chlorazifop cyhalofop diclofop fenoxaprop fluazifop haloxyfop quizalofop DIM herbicides alloxydim clethodim cycloxydim butroxydim sethoxydim Protox inhibitors Nitrophenyl ethers acifluorfen aclonifen bifenox fluorodifen fomesafen lactofen nitrofen oxyfluorfen Pyrimidinediones butafenacil saflufenacil Triazolinones carfentrazone sulfentrazone Pyridines dithiopyr fluroxypyr imazapyr thiazopyr triclopyr Quaternary Photosystem I inhibitors cyperquat diquat paraquat Thiocarbamates Benthiocarb Butylate S-Ethyl dipropylthiocarbamate prosulfocarb Triazines cellulose biosynthesis inhibitors indaziflam Photosystem II inhibitors ametryn atrazine cyanazine hexazinone metamitron metribuzin prometon prometryn propazine simazine simetryn terbuthylazine terbutryn Ureas Photosystem II inhibitors chlortoluron DCMU difenoxuron isoproturon linuron monuron monolinuron tebuthiuron ALS inhibitors chlorsulfuron flazasulfuron metsulfuron-methyl sulfometuron methyl tribenuron Others 3-AT aminocyclopyrachlor Bentazon clomazone dinoseb dinoterb juglone methazole metam sodium pyribenzoxim

v t e Pest control: Urea herbicides Phenylureas buturon chloroxuron chlortoluron DCMU defenuron difenoxuron fenuron isoproturon linuron methyldymron monolinuron siduron Ureas tebuthiuron noruron

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Adapted from the Wikipedia article [DCMU](https://en.wikipedia.org/wiki/DCMU) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/DCMU?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.