FORM 2 THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. A process for preparation of high purity, Aceiamiprid in a flaked form without use of solvent.
2. Gharda Chemicals Limited B-27 & 29 MIDC, Phase I, Dombivli, 421203, Dist. Thane, Maharashtra, India. An Indian company.
The following specification particularly describes and ascertains the nature of the invention and the manner in which it is to be performed :


A process for preparation of high purity Acetamiprid in a flaked form without use of solvent
BACKGROUND AND SUMMARY OF THE INVENTION Acetamiprid ; Chemical name : ( E)-N1-[(6-chloro-3-pyridyl)methyl]-N2-cyano-N1-methylacetamidine). Acetamiprid belongs to neonicotinoid class of insecticide, which has systemic insecticide activity. It is used to control hemiptera, especially aphids. The Patent US5304566, EU0456826(WO9104965) describe preparation of Acetamiprid and related compounds from penultimate intermediates, deploying solvents example Methanol/Ethanol using temperatures between ambient and boiling points of solvent which involves number of unit operations example filtration, drying, solvent recovery, further crop isolation and dusting problems during dry cake handling. We reasoned that since the penultimate intermediates 2-chloro-5-(methylaminomethyl)pyridine (I) and N-cyanomethyl-acetimidate (II) are liquids at around 30°C and bye product formed is a mole of alcohol per mole of reactants, the preparation could be conveniently carried out without the use of solvent, avoiding various unit operations, offering product in acceptable high purity and that too in flaked form. The cited examples bear out the success.
DETAILED DESCRIPTION OF THE INVENTION The equivalent moles of 2-chloro-5-(methylaminomethy!)pyridine(l) is reacted with N-cyanomethylacetimidate (II) or N-cyanoethylacetimidate not using a solvent at 35 to 60°C. N-cyanomethyracetimidate is added over a periad preferably 3 to 5 hrs controling the exothermicity upto 60°C. Raising the temperature to melting point of Acetamiprid to remove the by product methanol formed. The best method to prepare Acetamiprid is described in example 1
EMBODIMENTS Example 1:156.5 gm of high purity 2-chloro-5-(methyl amino methyl)pyridine liquified at 35°C is taken and to it is added 98 gm of N-cyanomethylacetimidate liquified at 30°C over 3 hrs. Maintain reaction mixture for 3 hrs or more to complete condensation and to produce methanol as reaction product. Raise temperature upto melting point of (III) to remove traces of methanol. The molten material 225.5 gm can be acid washed followed by water wash and dehydration to get flaked Acetamiprid (MP 100 to 103°C) which is > 99 % purity by IS HPLC.
2

CLAIMS We claim, 1. A process for the preparation of Acetamiprid comprising the steps of:
a. Reacting the high purity intermediates 2-chloro-5-(methylaminomethyl)pyridine and
N-cyanomethylacetimidate or N-cyanoethylacetimidate preferably at 35°C in
absence of solvent,
b. Maintaining the reaction temperature at 35° to 60°C preferably at 55°C for about 3
hours,
c. Heating to 102°C to remove methanol formed as bye product.
d. Flaking the molten material in the conventional way.

Dated 29th day of July 2004


Dr. AshokKumar Maganlal Malte Director-International Marketing & Development
GHARDA CHEMICALS LTD