METHOD OF SYNTHESIS OF ASYMMETRICALLY DISUBSTITUTED UREAS Russian patent published in 1994 - IPC

FIELD: organic chemistry. SUBSTANCE: product of the general formula RNHC/O/-N/R₁R₂/ where R - phenyl unsubstituted or substituted with a single or multihalide atoms, lower alkyl, lower alkoxy- arylhydroxy-group, trifluoromethyl, unsubstituted or once substituted with lower alkoxy-group, benzthiazolyl- or benzoxazolyl-group; R₁,R₂ - hydrogen or lower alkyl but R₁ and R₂ can not simultaneously mean hydrogen atom. Reagent 1: urea of formula (II) H₂N-C(O)-N(R₁R₂) where R₁,R₂ - as indicated above. Reagent 2: aromatic amine (III) of the formula RNH₂ and formula (IV) . Reaction conditions: process is carried out at 130-250 C in the presence of amine of formula (III) at the molar ratio of urea (II) to amine (III) and amine (IV) = 1:(0.5-0.7):(2-15). Method is used for synthesis of semiproducts used for synthesis of pyrethroids. EFFECT: improved method of synthesis.