CATALYTIC ACTION OF AZOLIUM SALTS .4. PREPARATIONS OF 4-AROYLQUINAZOLINES AND 4-AROYL-1H-PYRAZOLO[3,4-D]PYRIMIDINES BY CATALYTIC ACTION OF 1,3-DIMETHYLIMIDAZOLIUM IODIDE

The ability of 1,3-dimethylimidazolium iodide (1) to catalyze the aroy lation of the chloroheteroarenes 4-8 with arenecarbaldehydes 3 as sour ces of the aroyl groups was examined in order to develop a preparative method of aroylheteroarenes. In the presence of 1, the treatment of t he 4-chloroquinazolines (4: 2-H, 5: 2-Me, 6: 2-Ph) with arenecarbaldeh yde 3 in refluxing THF (tetrahydrofuran) or dioxane led to the 4-aroyl quinazolines (9: 2-H, 10: 2-Me, 11: 2-Ph) in excellent yields, as had been found with 1,3-dimethylbenzimidazolium iodide (2). Similar reacti on of the l-chloro-l H-pyrazolo [3,4-d]pyrimidines (7: 1-Ph, 8: 1-Me) with arenecarbaldehyde 3 yielded the corresponding 4-aroyl-1H-pyrazolo [3,4-d]pyrimidines (12: 1-Ph, 13: 1-Me). Compound 1 seems to catalyze the aroylation of a wider range of arenecarbaldehydes 3 as compared wi th 2.