Patent ID: 6570014
Filing Date: 2003-05-27
Classification: C07D

Abstract:
A process for preparation of triazolopyrimidine derivatives of the formula (I) whereinR1 represents a hydrogen or an alkyl radical of one to ten carbon atoms or a cycloalkyl radical of three to six carbon atoms, or an alkenyl radical of up to four carbon atoms; R2 represents a hydrogen, a halogen atoms, a hydroxyalkyl or alkyl radical of one to ten carbon atoms; R3 represents a hydrogen, a hydroxyalkyl or alkyl radical of one to four carbon atoms; comprises the steps of(a) reacting dialkyl cyanodithioimino carbonate of the formula (V), wherein R represents an alkyl radical of one to four carbon atoms, with alkyl amine of formula (IV), wherein R1 has the meaning as indicated above, in the present of an appropriate solvent at room temperature, and then add hydrazine dropwisely after heating to reflux, to give a compound of diamino-1,2,4-triazole of the formula (III), wherein R1 has the meaning as indicated above; (b) reacting the compound of the formula (III), wherein R1 has the meaning as indicated above, with aldehyde of the formula (VII), wherein R8 represents an alkyl radical of one to ten carbon atoms, or a phenyl, or a substituted phenyl, in the present of an organic solvent, to give a compound of imine of the formula (VI), wherein R1 and R8 have the meanings as indicated above; (c) formation of imine of the formula (VIII), wherein R1, R2, R3 and R8 have the meanings as indicated above, with selective condensation of &agr;, &bgr;-unsaturated acid derivatives of formula (II), wherein R2 and R3 have the meanings as indicated above, and R5 represents a halogen atom or OR9, wherein R9 represents an alkyl radical of one to six carbon atoms; and R6 represents an alkyl radical of one to six carbon atoms, and imine of formula (VI), wherein R1 and R8 have the meanings as indicated above, in the present of a base and a polymer inhibitor in an organic solvent at reflux temperature; and (d) formation of triazolopyrimidine derivatives of formula (I) from the compound of the formula (VIII), wherein R1, R2, R3 and R8 have the meanings as indicated above, in the present of an acid at room temperature to refluxing temperature.