6-AMINO-PURINE DERIVATIVE, MANUFACTURE AND PLANT GROWTH REGULATOR

摘要

Novel 6-aminopurine derivatives of the formula I IMAGE where R1 and R2 independently of one another in each case are hydrogen or C1-C6-alkyl, or one of the two radicals also denotes a phenyl or naphthyl radical, each of which is unsubstituted or monosubstituted to pentasubstituted by halogen, C1-C4-alkyl, C1-C4-halogenoalkyl, C1-C4-alkoxy, C1-C4-halogenoalkoxy, C1-C4-alkylthio, C1-C4-halogenoalkylthio, nitro, cyano, the carboxyl radical, a C1-C4-alkylcarbonyl or C1-C4-alkoxycarbonyl radical, or a carbamoyl radical CONR1R2, or R1 and R2 together with the nitrogen atom form a 5-7-membered heterocycle, R3 is hydrogen, C1-C6-alkyl or a phenyl radical which can be substituted as above, R4 is hydrogen or C1-C6-alkyl and R5 is hydrogen, or C1-C6-alkyl, or is a phenyl radical which can be substituted as above, and the acid addition salts of these compounds, with the proviso that at least one of the substituents R3, R4 and R5 is other than hydrogen and methyl, are obtained in good yield by cyclisation of 5-acylamino-4- amino-6-hydroxypyridine- or 5-acylamino-4-cyano- or -carbamoyl-1H- imidazole derivatives at elevated temperature in the presence of an excess of phosphorus pentoxide and a tertiary amine, and fusing on an amine salt. These compounds have useful plant-growth-regulating properties.