Topramezone
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| General | ||||||||||||||||
| Surname | Topramezone | |||||||||||||||
| other names |
[3- (4,5-dihydro-3-isoxazolyl) -2-methyl-4- (methylsulfonyl) phenyl] (5-hydroxy-1-methyl-1 H -pyrazol-4-yl) methanone |
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| Molecular formula | C 16 H 17 N 3 O 5 S | |||||||||||||||
| Brief description |
white odorless powder |
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| properties | ||||||||||||||||
| Molar mass | 363.39 g mol −1 | |||||||||||||||
| Physical state |
firmly |
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| density |
1.425 g cm −3 |
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| Melting point |
221.6 ° C |
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| boiling point |
300 ° C (decomposition) |
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| Vapor pressure |
<0.001 hPa (25 ° C) |
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| solubility |
soluble in water, acetone, toluene, n- heptane and ethyl acetate |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||
Topramezone is an active ingredient in crop protection and a chemical compound from the group of benzoylpyrazoles .
Extraction and presentation
Topramezone can be obtained through a six-step reaction. These are: condensation of 2,6-dinitrotoluene with organic nitrites , cyclization of the oxime formed with alkenes , reduction of the nitro group in the 3-isoxazolinylnitrobenzenes obtained, conversion of the aniline with dialkyl disulfides, bromination of the benzene ring of the benzene thioether , oxidation of the bromobenzene thioether on sulfur Carboxylation (bromine substitution) with carbon monoxide in the presence of alcohols .
properties
Topramezone is a white, odorless solid that is soluble in water.
use
Topramezone is used as a herbicide . It is used in post-emergence with maize and works against broad-leaved weeds and grasses. The effect is based on the inhibition of the enzyme 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) in sensitive plants, whereby the biosynthesis of plastoquinones and indirectly of carotenoids is prevented. This disrupts the synthesis and function of the chloroplasts and leads to the oxidative breakdown of chlorophyll .
Admission
An application for inclusion of the compound in Annex I of Directive 91/414 / EEC was submitted by BASF in May 2003 . A provisional approval ended on April 30, 2015. In Germany, Austria and Switzerland, no pesticides with this active substance are approved.
Individual evidence
- ↑ a b c d e f g h i data sheet Topramezone at Sigma-Aldrich , accessed on May 20, 2017 ( PDF ).
- ↑ a b Entry on Topramezone in the Hazardous Substances Data Bank , accessed September 10, 2012.
- ↑ a b c d e Entry on Topramezone in the Pesticide Properties DataBase (PPDB) of the University of Hertfordshire , accessed on August 1, 2013.
- ↑ EPA: Pesticide Fact Sheet - Topramezone (PDF; 33 kB), August 10, 2005.
- ↑ Topramezone - a new herbicidal active ingredient for highly selective millet and weed control in maize (PDF; 150 kB), Journal of Plant Diseases and Protection, Journal of Plant Diseases and Plant Protection, special issue, 1023-1031 (2006), ISSN 1861-4051 .
- ↑ General Directorate Health and Food Safety of the European Commission: Entry on Topramezone in the EU pesticide database ; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 12, 2016.