An organic photochromic compound: (2S)-2′-ethoxy-1,3,3-trimethyl-6′-(piperidin-1-yl)spiro[indoline-2,3′-3′H-naphtho[2,1-b][1,4]oxazine]

In the course of our synthesis of hybrid photochromic compounds, the unexpected new organic photochromic title compound, C₂₉H₃₃N₃O₂, (I), was obtained. It is a derivative of the parent spirooxazine 1,3,3-trimethyl-6′-(piperidin-1-yl)spiro[indoline-2,3′-3′H-naphtho[2,1-b][1,4]oxazine], (II). The 2′-ethoxy group gives (I) different photochromic properties from its parent spirooxazine (II).