Patent EA-000955-B1 (EA)
Title: Processes for preparing pesticidal intermediates
Inventor: HAWKINS DAVID WILLIAM
IPC: C07D231/38
Filed: 1997-03-03
Abstract: 1. A process for preparing a compound of formula (1):   wherein R represents straight- or branched- chain alkyl having from 1 to 18 carbon atoms, or a salt thereof, which comprises the reaction of a cyanoacetate of formula (II): RO2C-CH2CN   II wherein R is as defined above, with a cyanide salt, and formaldehyde or a source thereof. 2. A process according to claim 1 in which the cyanide salt is an alkali or alkaline earth metal salt. 3. A process according to claim 2 wherein the cyanide salt is sodium or potassium cyanide. 4. A process according to claim 1, 2 or 3, wherein R represents straight- or branched-chain alkyl having from 1 to 6 carbon atoms. 5. A process according to any one of claims 1 to 4, wherein the compound of formula (11) is ethyl cyanoacetate. 6. A process according to any one of claims 1 to 5, wherein the source of formaldehyde is paraformaldehyde. 7. A process according to any one of claims 1 to 6, wherein the reaction is performed in presence of a solvent which is an alcoholic medium. 8. A process according to any one of the preceding claims, wherein the reaction is carried out at a temperature from about 0 degree C to about 1200 degree C. 9. A process according to any one of the preceding claims in which the reaction is performed using about 1 molar equivalent of the compound of formula (II); about 0.95 to 1.0 molar equivalents of cyanide salt; and about 1 molar equivalent of formaldehyde compound. 10. A process according to any one of the preceding claims in which the reaction mixture is acidified after reaction of the cyanoacetate of formula (II) with the cyanide salt and formaldehyde. 11. A process according to any one of the preceding claims, in which the reaction is performed under substantially anhydrous conditions. 12. A process for the preparation of a compound of formula (III)    wherein R1 is cyano; W is nitrogen or -CR4; R2 and R4 independently represent halogen; and R3 represents halogen, haloalkyl, haloalkoxy or SF5; which process comprises: (a) reacting a cyanoacetate of formula (II)  RO2C-CH2CN   II wherein R represents straight- or branched- chain alkyl having from I to 18 carbon atoms, with a cyanide salt and formaldehyde or a source thereof, to give a compound of formula (I) as defined in claim l;and  (b) reacting the compound of formula (I) thus obtained with the diazonium salt of a compound of formula (IV):   wherein W, R2 and R3 are as defined above; to give a compound of formula (V):   wherein W, R, R1, R2 and R3 are as defined above, followed by the cyclisation of said compound of formula (V). 13. A process according to claim 12 in which the product of reaction step (a) is treated with an alcoholic solution of an acid, preferably a mineral acid. 14. A process according to claim 12 or 13 in which the molar ratio of the compounds of formula (II):(IV) is from about 1.5:1 to about 1:4, preferably from about 1.3:1 to about 1:1. 15. A process according to claim 12, 13 or 14 in which reaction step (a) is performed under substantially anhydrous conditions. 16. A process according to any one of claims 12 to 15 in which the cyclisation is effected by hydrolysis of the compound of formula (V). 17. A compound of formula (V):   wherein R1 is cyano; W is nitrogen or -CR4; R2 and R4 independently represent halogen; and R3 represents halogen, haloalkyl, haloalkoxy or SF5. 18. Ethyl 2,3-dicyano-2 -[(2,6-dichloro-4- trifluoromethylphenyl)azo]propionate.