Patent ID: 8318932

Claim:
A process for preparing a 4-aminoquinazoline compound having the formula (3): in which each of R 1 , R 2 , R 3 and R 4 independently represents a group selected from the group consisting of a hydrogen atom, an alkyl group having 1-12 carbon atoms, a cycloalkyl group having 1-12 carbon atoms, an aralkyl group having 7-15 carbon atoms, an aryl group having 6-14 carbon atoms, a halogen atom, an alkoxy group having 1-12 carbon atoms, an alkylthio group having 1-12 carbon atoms, an arylthio group having 6-14 carbon atoms, nitro, cyano, amino, carboxyl, ester, or amide, in which the alkyl, cycloalkyl, aralkyl, aryl, alkoxy, alkylthio, arylthio, and amino may have a substituent which is selected from the group consisting of alkyl, cycloalkyl, aryl, carboxyl, alkoxycarbonyl, aryloxycarbonyl, halogenated alkyl, cyano, alkoxy, benzyloxy, piperidyloxy, pyranyloxy, aryloxy, secondary amino, heterocyclic amino, thioalkoxy, thioaryloxy, and halogen, or R 1 , R 2 , R 3 and R 4 are combined to form a ring; R 5 represents a hydrogen atom or a hydrocarbyl group which can have a substituent which is selected from the group consisting of alkyl, cycloalkyl, aryl, carboxyl, alkoxycarbonyl, aryloxycarbonyl, halogenated alkyl, cyano, alkoxy, benzyloxy, piperidyloxy, pyranyloxy, aryloxy, secondary amino, heterocyclic amino, thioalkoxy, thioaryloxy, and halogen; and R 6 is a hydrogen atom or a hydrocarbyl group, which comprises: a first step of reacting a quinazolin-4-one compound having the formula (1): in which R 1 , R 2 , R 3 and R 4 have the same meaning as above, with a chlorinating agent in an amount of 1.0 to 2.5 moles based on one mole of the quinazolin-4-one compound, said chlorinating agent being selected from the group consisting of phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride, sulfuryl chloride and nitrosyl chloride, in a first organic solvent in the presence of an organic base, to give a reaction mixture containing a reaction product, and a second step comprising adding an amine compound having the formula (2) to the reaction mixture: R 5 —NH—R 6 (2) in which R 5 and R 6 have the same meaning as above, in the presence of a second organic solvent, wherein the first reaction solvent is selected from the group consisting of an aliphatic hydrocarbon, a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, and a halogenated aromatic hydrocarbon and wherein the second reaction solvent comprises the first reaction solvent and nitrile or ketone added thereto.