| abstract |
The present invention provides a process for preparing a compound of thengeneral formula (I):n nwherein R 1 to R 5 are independently selected from hydrogen, halogen,nC 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl or C 1-6 alkoxy, all optionally substituted bynone or more of halogen, hydroxy and aryl groups, as well as beingnindependently selected from amino, mono- or disubstituted amino, alkenyloxy,nacyl, acyloxy, cyano, nitro, aryl and alkylthio groups, which process comprisesnreacting a compound of the general formula (II):n nwherein R 1 to R 5 are as defined in formula (I), with aminoguanidinenbicarbonate in a mixture of a water-soluble solvent and polyphosphoric acid. |