METHOD FOR PREPARING 2,2-DICHLORO- OR DIBROMOPHENYLACETIC ACID ALKYL ESTERS Russian patent published in 2008 - IPC C07C67/22 C07C67/54 C07C67/58 C07C69/65 C07C253/30 C07C255/35 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to an improved method for synthesis of 2,2-chloro- or dibromophenylacetic acid alkyl ester of the formula (I): wherein X means Cl or Br; n can be a whole number from 1 to 5; R means hydrogen atom, (C₁-C₈)-alkyl, aryl, heteroaryl, (C₁-C₈)-alkaoxy, aryloxy group or halogen atom; R1 means (C₁-C₈)-alkyl. Method involves interaction of 2,2-dichloro- or dibromophenylacetonitrile of the formula (II): wherein X, n and R are given above in 0.8-2 moles of water per 1 mole of nitrile of the formula (II) with 1-8 moles of alcohol of the formula (III): R1OH (III) wherein R1 is given above per 1 mole of nitrile of the formula (II) in the presence of from 1 to 3 moles of HCl or HBr per 1 mole of nitrile of the formula (II) in the presence if necessary of an inert solvent under conditions of this reaction, at reaction temperature from 30 to 60°C. Then method involves heating to temperature 60-100°C and keeping at this temperature. After termination of reaction the reaction mixture is cooled to temperature from 20 to 40°C, diluted with water and the corresponding 2,2-dichloro- or dibromophenylacetic acid alkyl ester of the formula (I) is isolated. Also, invention relates to a method for synthesis of 2,2-dichloro- or dibromophenylacetic acid alkyl ester of the formula (I): wherein X means Cl or Br; n can mean a whole number from 1 to 5; R means hydrogen atom, (C₁-C₈)-alkyl, aryl, heteroaryl, (C₁-C₈)-alkoxy, aryl oxy group or halogen atom; R1 means (C₁-C₈)-alkyl wherein in the first step of synthesis a possibly substituted benzyl cyanide of the formula (IV): wherein n and R are given above is subjected for interaction with chlorine in the presence of the catalytic amount of gaseous hydrogen chloride or with brominating agent to yield the corresponding nitrile of the formula (II): wherein n, X and R are given above, and formed exhausting gas HCl or HBr is used in the second step for conversion of nitrile of the formula (II) to corresponding 2,2-dichloro- or dibromophenylacetic acid alkyl ester of the formula (I). Conversion to the corresponding 2,2-dichloro- or dibromophenylacetic acid alkyl ester of the formula (I) at the second step occurs in 0.8-2 moles of water per 1 mole of nitrile of the formula (II), 1-8 moles of alcohol of the formula (III): R1OH (III) wherein R1 is given above per 1 mole of nitrile of the formula (II) in the presence of HCl or HBr as a gas exhausting from the first step taken in the amount 1-3 moles per 1 mole of nitrile of the formula (II), and if necessary in the presence of a solvent, at the reaction conversion from 30 to 60°C. Then the process involves heating to temperature 60-100°C and keeping at this temperature, and after termination of reaction the reaction mixture is cooled to temperature from 20 to 40°C and diluted with water. Methods provide preparing the end products with high yields and high purity.

EFFECT: improved methods of synthesis.

10 cl, 8 ex