Synthesis of Benzo[g]quinazoline Derivatives

The general procedures for the preparation of compounds 1–17 were previously reported for the preparation of their analogues [13 (link),17 (link)]. Briefly, in the basic medium, the reaction of ethyl(methyl)isothiocyanate with 3-amino-2-naphthaoic acid under a refluxing condition in DMF for 3–5 h afforded the parent intermediates 1 and 2 in good yields (Scheme 1). When compound 1 or 2 was treated with the appropriate alkyl/heteroalkyl halide in the presence of a base at 80 °C for 20 h, benzo[g]quinazolines 3–15 were obtained in good to high yields. Hydrazinolysis of 1 and 2 in boiling DMF for 15–18 h afforded 16 and 17, respectively. Their characterization data are reported herein as follows: