Synthesis of 2-aminoquinazolines fromortho-fluorobenzaldehydes

The reaction of guanidine carbonate with various ortho-fluorobenzaldehydes in N,N-diinethylacetamide was investigated as a potential route for preparing 2-aminoquinazolines. Eleven new 2-aminoquinazolines were elaborated in this manner in low to moderate yields. In general the best results were obtained with ortho-fluorobenzaldehydes possessing an electron withdrawing substituent at the other ortho position. Complex mixtures were obtained using 2-fluorobenzaldehyde, 2,5-difluorobenzaldehyde and 2-fluoro-5-methoxybenzaldehyde which were not resolved.