DCMU

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DCMU
Skeletal formula of DCMU
Ball-and-stick model of the DCMU molecule
Names
Preferred IUPAC name
N′-(3,4-Dichlorophenyl)-N,N-dimethylurea
Other names
3-(3,4-Dichlorophenyl)-1,1-dimethylurea, Karmex, Diuron, Direx
Identifiers
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
100.005.778 Edit this at Wikidata
EC Number
  • 206-354-4
KEGG
RTECS number
  • YS8925000
UNII
UN number 3077, 2767
  • 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) checkY
    Key: XMTQQYYKAHVGBJ-UHFFFAOYSA-N checkY
SMILES
  • Clc1ccc(NC(=O)N(C)C)cc1Cl
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:
GHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
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)
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).

DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an

algicide and herbicide of the aryl urea class that inhibits photosynthesis. It was introduced by Bayer
in 1954 under the trade name of Diuron.

History

In 1952, chemists at

analogs 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-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

reductant potential
).

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

NADP+
to NADPH. In fact, it was found that DCMU not only does not inhibit the cyclic photosynthetic pathway, but, under certain circumstances, actually stimulates it.[6][7]

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

  1. ^ a b c d e f NIOSH Pocket Guide to Chemical Hazards. "#0247". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ 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. 
  3. .
  4. ^ "Urea herbicides". alanwood.net. Retrieved 2021-03-26.
  5. S2CID 84205263
    .
  6. .
  7. ^ "Diuron". National Center for Biotechnology Information. United States National Library of Medicine. Retrieved 9 November 2021.
  8. ^ Linda, Taylor; Esther, Rinde (1997-05-08). Carcinogenicity Peer Review of Diuron (PDF) (Memorandum). Washington, D.C.: United States Environmental Protection Agency. 20460.
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