| abstract |
The invention relates to a process for the preparation of heterocyclic derivatives of the general formula (I) (wherein X, Y and Z are oxygen or sulfur, R 1 is alkyl of 1-4 carbon atoms , R2 represents furanyl, thienyl, 1,3-benzodioxolyl, phenyl or phenyl substituted by one or two alkyl, halogen, halomethyl, methoxy, nitro and R 3 represents cycloalkyl of 5 to 7 carbon atoms, tetrahydropyranyl, tetrahydropyranyl , 1,4-dioxanyl, methylpiperidinyl, 5-methyl-2,3-dihydro-1,4-thioxanyl, the cycloalkyl being optionally substituted with one or two methyl groups consisting of treating a compound of formula general formula II wherein Y, X, R 1 and R 2 are as defined above with an isothiocyanate of the general formula III: wherein R 3 and Z are as defined above, in a an inert solvent selected from toluene, tetrahydrofuran, dimethylsulfoxide and benzene, in the presence of a catalyst selected from 1,3-diazabicyclo [5,4,0] undec-7-ene, sodium hydride, tertiary amine, stannous chloride, boron trifluoride and zinc chloride at a temperature between 0 ° C and room temperature . |