Specific features of the reactions of quinazoline and its 4-hydroxy and 4-chloro substituted derivatives with C-nucleophiles

Reactions of quinazoline 1 with indole, pyrogallol and 1-phenyl-3-methylpyrazol-5-one in the presence of acid led to C-4 adducts 2, 3 and 5. Adduct 4 is formed by heating 1 with 1,3-dimethylbarbituric acid without acid catalysis. 1-Phenyl-3-methylpyrazol-5-one reacts with 1 without acid catalysis to form dipyrazolylmethane 6. 4-Chloroquinazoline 8 reacts with 1-phenyl-3-methylpyrazol-5-one to form 4-(1-phenyl-3-methyl-5-oxopyrazol-4-yl) quinazoline 9 and dipyrazolylmethane 6. Heating 8 with 2-methylindole leads to the formation of 4-(2-methylindol-3-yl) quinazoline 10 and tris(2-methylindol-3-yl)methane 11.