Synthesis of Fused Pyrimidines from Nitroarenes via ortho-Nitroaromatic Carboximes

A synthesis of functionalized fused pyrimidine derivatives from the respective ortho-nitroaroma­tic carboximes is described. Commercially available nitroarenes were transformed according to a known manner into the ortho-nitroaromatic carboximes. Selective catalytic reduction of the nitro group in these compounds followed by condensation of the amines formed with various orthoesters, resulted in the formation of imidates. Subsequent cyclocondensation of the ortho-neighbouring iminoether and oxime groups with ammonia led to the desired products.