METHOD OF PREPARING LAMBDA CIGALOTRINE BY ISOMERIZATION Russian patent published in 1999 - IPC

FIELD: chemistry of polymers. SUBSTANCE: invention describes method of preparing lambda cigalotrine as racemic modification containing 3-alpha- cyano-3-phenoxybenzyl, 1R, 3R-3-(2,2-chloro-3,3,3- trifluoroprop-1-ene-1-yl)-2,2-dimethylcyclopropane carboxylate and enantiomer thereof. Method comprises treating cigalotrine as mixture of four isomers in approximately equal amounts containing two isomers that make up lambda cigalotrine and epimers of these two isomers in solution or as suspension in isopropanol. Treatment is carried out in moist isopropanol containing 2 to 15 vol % water with sodium cyanide in amount from 0.5 to 15 mole % based on amount of cigalotrine at 10-20 C. EFFECT: simpler process. 4 cl, 1 ex, 1 tbl