Photochromic oxazine compounds and methods for their manufacture

#The present invention relates to oxazine compounds. In particular, the invention provides oxazine compounds and methods for their manufacture, which compounds are useful as photochromic compounds.

#Various classes of photochromic compounds have been synthesized and suggested for use in applications in which reversible color changes or darkening is induced by sunlight. For example, spirooxazine and chromene compounds are known for excellent fatigue resistance. Additionally, photochromic 2,2-disubstituted [2H-1,4]-naphthoxazine compounds, such as those are disclosed in U.S. Pat. No. 5,801,243, are known. These compounds have better fatigue resistance than chromene compounds, but are disadvantageous in that methods for their preparation are extremely limited. Thus, a need exists for additional photochromic oxazine compounds that overcome the disadvantages of the known compounds.

#The present invention provides oxazine compounds having an aromatic substituent at the 2 position of the oxazine moiety, as well as methods for synthesizing these compounds.

#Step 1.

#Into a 100 ml three-necked flask was charged solid KOH (3.30 g, 0.05 mole) and 25 ml acetonitrile under argon which was then heated to reflux. Benzophenone (9.1 g, 0.05 mole) in 20 ml acetonitrile was added in a stream with stirring. After 8 hours of reflux, the hot reaction solution was poured onto 100 g crushed ice and extracted with dichloromethane (3×15 ml). The combined organic extract was washed with water, dried over anhydrous sodium sulfate, and filtered. Solvent was removed, the residue was purified by flash chromatography on silica gel (ether-hexane 1:5 as eluent), 7.9 g colorless oil was obtained (yield: 77%). 1HNMR showed the product to have a structure consistent with 3,3-diphenyl-acrylonitrile.

#1HNMR (CDCl3): δ5.75 (s, 1H), 7.27-7.50 (m, 10H).