| abstract |
NEW MATERIAL:The naphthacene derivative of formula VII (X is H or halogen). EXAMPLE:1,2,3-Tri-t-butyl-5,11-dibromonaphthacene. USE:An optical recording medium, optical memory material, etc. It exhibits photochromism in long-wavelength region, has excellent thermal stability of isomers and is useful as a photochromic compound. PREPARATION:A compound of formula VII wherein both Xs are Br can be produced by (1) reacting a compound of formula I with a compound of formula VIII and isoamyl nitrite, (2) converting the resultant compound of formula II into the compound of formula IV without separating from the system, (3) reacting the compound of formula IV with a compound of formula III and n-butyllithium at room temperature, (4) heating the obtained compound of formula V at 120-170 deg.C to obtain a compound of formula VI and (5) reacting the product with N-bromosuccinmide and azoisobutyro-nitrile at 40-80 deg.C. Another compound of formula VII wherein both Xs are H is produced by reacting the compound of formula VI with O2 at 70-90 deg.C. |