Zur Kenntnis des Perylens und seiner Derivate. (2. Mitteilung)

Columnar Benzoperylene‐Hexa‐ and Tetracarboxylic Imides and Esters: Synthesis, Mesophase Stabilisation and Observation of Charge‐Transfer Interactions between Electron‐Donating Esters and Electron‐Accepting Imides

“…4,4'-Dicyanobinaphthyl (9), obtainable either by diazotisation of naphthidine [25] or, as we found, by Rosenmund-von Braun cyanuration of readily available 4,4'-dibromobinaphthyl (10), [26] is known to cyclise to give 3,10-dicyanoperylene (11) in AlCl 3 . [27] To this, we found we could selectively add maleic anhydride by benzogenic oxidative Diels-Alder reaction at the bay region of the unsubstituted, less electron-depleted side of the perylene moiety. Purification of the resulting 5,10-dicyanobenzoA C H T U N G T R E N N U N G [ghi]perylene-1,2-dicarboxylic acid after transformation into the readily soluble bis-2ethylhexyl ester 12, followed by fourfold hydrolysis to the tetraacid and re-esterification, yielded the benzo- When comparing the phase behaviour of tetraethylester 13 a with that of hexaethylester 7 a, a greatly enhanced mes-ogenicity was observed.…”

“…At room temperature, 10 % hydrochloric acid (50 mL) was added and the mixture was boiled with stirring until all of the solid was suspended and no longer adhered to the flask. The orangebrown solid (crude 3,10-dicyanoperylene 11) [27] was then collected by filtration, washed with water and methanol, and then refluxed with p-chloranil (7.5 g, 31 mmol) in maleic anhydride (75 g) overnight. The mixture, while still hot and liquid, was poured into acetone (500 mL), stirred for 15 min, and the precipitate (crude 5,10-dicyano-benzoperylene-1,2-dicarboxanhydride) was collected by filtration.…”

“…[27] To this, we found we could selectively add maleic anhydride by benzogenic oxidative Diels-Alder reaction at the bay region of the unsubstituted, less electron-depleted side of the perylene moiety. Purification of the resulting 5,10-dicyanobenzoA C H T U N G T R E N N U N G [ghi]perylene-1,2-dicarboxylic acid after transformation into the readily soluble bis-2-ethylhexyl ester 12, followed by fourfold hydrolysis to the tetraacid and re-esterification, yielded the benzo-A C H T U N G T R E N N U N G [ghi]perylene 1,2,5,10-tetracarboxylic ethyl and 2-ethylhexyl esters 13 a and 13 b (Scheme 4).…”

Comparison of Oxidative Aromatic Coupling and the Scholl Reaction

“…Perylene ( 8 ) was also obtained from naphthalene ( 9 ) without isolation of the intermediate 7 ; however, because of some decomposition, the yield of 8 was poor 12. Later, the reaction of 4,4′‐dicyano‐1,1′‐binaphthalene was reported to give the corresponding coupling product in 72 % yield 13…”

“…Weitzenböck and Seer reported that dinaphtho[2,1‐ b :1′,2′‐ d ]furan undergoes cyclization to peryleno[1,12‐ bcd ]furan in the presence of AlCl 3 , with the concomittent formation of perylen‐1‐ol 13. Polyphosphoric acid has been used to induce the cyclization of precursor 45 (Scheme ) 55.…”