Studien zur Synthese helicaler Naphthochinon‐Oligomerer, I. 2,2′;3′,2″‐Ter‐ und 2,2′;3′,2″;3″,2‴‐Quater(1,4‐naphthochinon)

Studies in the Synthesis of Helical Naphthoquinone Oligomers, I. — 2,2′;3′,2″‐Ter‐ and 2,2′;3′,2′;3′,2‴‐Quater(1,4‐naphthoquinone) 2,2′;3′,2′‐Ter(1,4‐naphthoquinone) ( 6a ) and 2,2′;3′,2″;3″,2‴‐quater(1,4‐naphthoquinone) ( 8a ) are obtained by cooxidation of the phenolic precursors 16a and 2b . It is shown, that partially reduced 6a cyclizes under basic conditions yielding triphthaloylbenzene ( 7 ); therefore, it is also a possible intermediate of the synthesis of 7 by phenol/quinone addition of 2a to 1a . Spectroscopic data suggest that the tetrameric hydroquinonylquinone 8b is stabilized by hydrogen bonding, forming a helical quinhydron structure.