On the Derivatives of 3:4-Benzotropolone

One hundred years of benzotropone chemistry

“…Reaction of 7-hydroxy-2,3-benzotropone (241): Various monosubstitution products 289 – 291 of 7-hydroxy-2,3-benzotropone ( 241 ) were readily prepared by Nozoe’s group ( Fig. 12 ) [ 174 ]. The synthesis of bromo-derivative 290 from 241 was also reported by Cook’s group [ 166 ].…”

“…The synthesis of bromo-derivative 290 from 241 was also reported by Cook’s group [ 166 ]. The coupling of 241 with aryldiazonium chlorides resulted mainly in the formation of 5-phenyl- and p -tolylazo-coupling products 292 [ 175 ] and 293 [ 174 ] ( Fig. 12 ).…”

“…Catalytic hydrogenation of 241 over Adams's catalyst (PtO 2 . H 2 ) gave the diol 295 ( Scheme 49 ) [ 162 , 165 , 174 ]. Treatment of 241 with alkaline hydrogen peroxide caused degradative fission to give o -carboxycinnamic acid ( 296 ) [ 165 ], while nitration of 241 with nitric acid in an acetic acid solution afforded 2,4-dinitro-1-naphthol ( 297 ) [ 175 ] ( Scheme 49 ).…”

“…A short communication describing how 3,4-benzotropolone ( 241A ) can be chlorinated to yield monochloro-3,4-benzotropolone was presented by Nozoe’s group [ 174 ]. Ebine studied in more detail the chlorination and iodination of 241A ( Scheme 69 , Scheme 70 and Fig.…”