A new and efficient method for the synthesis of 3,1-benzoxazine compounds by direct cyclocondensation of 5-nitro-2-cyanoaniline with cyclic ketones using zinc chloride as a catalyst was reported. Using this method, 6-nitro-1,2-dihydro-2,2-(1,5-pentylene)-4-imino-4H-3,1-benzoxazine (4a) was synthesized with its structure determined by elemental analysis, IR, ¹H NMR, ¹³C NMR and X-ray single crystal diffraction analysis. Crystal data: monoclinic, space group: P2₁/c, a＝0.66339(13) nm, b＝2.5329(5) nm, c＝0.73756(15) nm, β＝91.85(3)°, V＝1.2387(4) nm³, Z＝4, D_c＝1.401 g/cm³, F(000)＝552, µ＝0.102 mm^－1, R＝0.0994, wR＝0.3001.