Thiamethoxam

3 - (2 -chloro -thiazol- 5 -ylmethyl) -5-methyl (1,3,5 ) oxadiazinan -4- ylidene -N- nitroamine

Brown solid

Fixed

1.57 g · cm -3

139.1 ° C

147 ° C ( decomposition)

6.6 x 10-9 Pa ( 25 ° C)

• Sparingly soluble in water (4.1 g · l-1 at 25 ° C)
• Soluble in dichloromethane ( 110 g · l-1 ), acetone (48 g · l-1 ) and methanol (13 g · l -1)

Attention

Template: Infobox chemical / molecular formula search available

Thiamethoxam is a chemical compound selected from the group of neonicotinoids.

Production and representation

Thiamethoxam may be prepared by reaction of N-methyl- N' -nitroguanidine to give N- methyl-4- (N -nitro- imino) - perhydro -1 ,3,5- oxadiazine and subsequent ring coupling with 2-chloro - 5-chloromethyl -1 ,3- thiazole are obtained in the presence of a base.

Properties

Thiamethoxam is a brownish solid. It is stable to hydrolysis at a pH of 5 and 7, but decomposes at a described pH 9 thiamethoxam as E / Z - mixture. It is generally believed that the activation energy for the E ↔ Z interconversion is low for the C = N bond, and that the equilibrium mixture rapidly sets at room temperature.

Use

Thiamethoxam is used as a wood preservative and insecticide. It is ( longhorn ) used against termites ( Gelbfüßige Bodentermite, Reticulitermes hageni, Reticulitermes santonensis ) and beetles. The effect is based on the irreversible blockade of postsynaptic nicotinergic acetylcholine receptors in the central nervous system. It was developed as part of a 1985 by Ciba- Geigy (now Syngenta ) launched the research program of neonicotinoids, first synthesized in 1991 and introduced to the market in 1998.

In 2011, in the U.S., about 550 t thiamethoxam used, of which about one-third in soybean and corn as well as fourth in cotton cultivation.

Regulation

EU

In the EU and 26 Member States the application of thiamethoxam is approved, but because of risks to honeybees from 1 December 2013 for two years for several important uses, such as the seed treatment of maize and oilseed rape, severely restricted (see neonicotinoids # EU restrictions as of 2013 ). The Permitted daily dose is 0.026, the Acute Reference Dose 0.5 and the Acceptable Operator Exposure 0.08 milligrams per kilogram of body weight per day.

Most approvals thiamethoxamhaltiger mordant apply to sugar beet, maize, oilseed rape and potatoes, in addition to a number of other plant species.

In the European Union thiamethoxam was recorded with effect from 1 February 2007 for use as insecticide in the list of permitted pesticide active ingredients. The approval was supplemented in 2010 by regulations designed to reduce the emission of dust during thiamethoxanhaltigen seed treatment, storage, and seeding.

In Germany, Austria and Switzerland pesticides are approved with this drug. In Germany, the Federal Office of Consumer Protection and Food Safety ( BVL) due to the high toxicity of neonicotinoids on bees and a proven bee mortality decided the suspension of the registration of seed treatment products for corn and canola with clothianidin, thiamethoxam and imidacloprid by clothianidin on 15 May 2008. The suspension of the marketing authorizations for the treatment of canola seed was lifted on 25 June 2008. The use of thiamethoxam, clothianidin and imidacloprid seed treatment for maize was prohibited by a regulation of the BMELV of 11 February 2009.