ChemicalBook CAS DataBase List Imidacloprid

Imidacloprid synthesis

4synthesis methods

Product Name:Imidacloprid
CAS Number:138261-41-3
Molecular formula:C9H10ClN5O2
Molecular Weight:255.66

Reduction of 2-chloro-5-pyridinecarbonyl chloride (8) to 2-chloro-5-hydroxymethylpyridine (9) was carried out by excess NaBH4 in water, which was converted to the chloride (10) by SOCl2 . Imidacloprid was obtained by the coupling reaction of 10 with 2-nitroiminoimidazolidine (11) in acetonitrile with potassium carbonate as base. This method was successfully applied to the synthesis of [3H]imidacloprid (12) using NaB[3H]4 as the tritium source (40).
Technical production starts with the Tschitschibabin reaction of 3-methylpyridine giving 2-amino-5-methylpyridine (14), which is transformed to the chloride (15) by the Sandmeyer reaction in the presence of hydrogen chloride. A successive operation of chlorination of the methyl group to 10 and the subsequent substitution of the active chloride with ethylene diamine to 16 are carried out without isolation of the intermediates. The final product is produced by ring formation with nitroguanidine. This multistep process affords the product at a purity of >95% (41).

101990-44-7 Synthesis

N-(2-CHLORO-5-PYRIDYLMETHYL)ETHYLENEDIAMINE

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Yield:138261-41-3 80%

Reaction Conditions:

in dichloromethane;

Steps:

5 1-(2-Chloro-5-pyridylmethyl)-2-(nitroimino)imidazolidine:

(Example 5.) 1-(2-Chloro-5-pyridylmethyl)-2-(nitroimino)imidazolidine: To a solution of 2.50 g (15 mmol) of dimethyl N-ni troimidodithiocarbonate in 10 ml of dichloromethane, 2.78 a (15 mmol) of N-(2-chloro-5-pyridylmethyl)ethylenediamine was added with stirring at 25 to 32°C under ice cooling. The reaction mixture was stirred at room temperature for more 3 hours, followed by evaporating the solvent under reduced pressure. Crude crystal deposited was recrystallized from ethanol and dried. Thus, 3.07 g of the desired compound was obtained, The yield was 80.0 %. Melting point 134-6 °C.

References:

EP500952,1992,A1

101990-44-7 Synthesis

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