DCMU
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Names | |
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Preferred IUPAC name
N′-(3,4-Dichlorophenyl)-N,N-dimethylurea | |
Other names
3-(3,4-Dichlorophenyl)-1,1-dimethylurea, Karmex, Diuron, Direx
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Identifiers | |
3D model (
JSmol ) |
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ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard
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100.005.778 |
EC Number |
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KEGG | |
PubChem CID
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RTECS number
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UNII | |
UN number | 3077, 2767 |
CompTox Dashboard (EPA)
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SMILES
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Properties | |
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) |
42 mg/L | |
Vapor pressure | 0.000000002 mmHg (20°C)[1] |
Hazards | |
GHS labelling: | |
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Warning | |
H302, H351, H373, H410 | |
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)
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none[1] |
REL (Recommended)
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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).
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DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an
History
In 1952, chemists at
Synthesis
As described in the du Pont patent, the starting material is 3,4-dichloroaniline, which is treated with phosgene to form a isocyanate derivative. This is subsequently reacted with 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
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.[citation needed]
However, because it blocks electrons produced from water oxidation in
Because of these effects, DCMU is often used to study energy flow in photosynthesis.
Toxicity
DCMU (Diuron) has been characterized as a known/likely human carcinogen based on animal testing.[8][9]
References
- ^ a b c d e f NIOSH Pocket Guide to Chemical Hazards. "#0247". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b US patent 2655445, 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.
- ISBN 9780123743671.
- ^ "Urea herbicides". alanwood.net. Retrieved 2021-03-26.
- S2CID 84205263.
- PMID 16665372.
- ^ "Diuron". National Center for Biotechnology Information. United States National Library of Medicine. Retrieved 9 November 2021.
- ^ Linda, Taylor; Esther, Rinde (1997-05-08). Carcinogenicity Peer Review of Diuron (PDF) (Memorandum). Washington, D.C.: United States Environmental Protection Agency. 20460.