Synthesis, crystal structure and photochromism of a novel spiro[indoline–naphthaline]oxazine derivative

• A new spirooxazine derivative was designed and synthesized.
• X-ray diffraction of the title compound has been reported.
• Photochromic properties were studied by means of UV/visible.
• The fluorescence emission spectra in solvents was analyzed.

A new spiro[indoline–naphthaline]oxazine derivative, 12-methoxy-14,14-dimethyl-17-(piperidin-1-yl)-7,8,14,15a-tetrahydro-4bH-naphtho[1″,2″:5′,6′][1,4]oxazino[3′,2′:2,3][1,4]oxazino[4,3-a]indole (1), was successfully synthesized, and its structure was characterized by 1H NMR, 13C NMR, IR, HRMS and single-crystal X-ray diffraction method. X-ray diffraction indicates that benzene and naphthalene rings of compound 1 are almost perpendicular, and the piperidine ring at the 6′-C site is in a chair conformation. In the packing diagram, a couple of short intermolecular distances such as the intermolecular short contact are observed. The photochromic properties of compound 1 have been fully investigated in different solvents, it was found that it exhibited excellent photochromism properties in solvents.