Tribenzo oxepins

Dagegen konnten Umklappschwellen fiir benzologe Oxepine be-stimmt werden. 1-Methyl-tribenzo-oxepin-3-carbonsaure 111 liefert mit Brucin ein mutarotierendes Salz, aus dem sich auch die bei Raumtempe-ratur auBerordentlich rasch racemisierende rechtsdrehende Saure (a 1/2 = 195 sec-1 bei 20,5 °C zlGto,5°c = 20,8 kcal/Mol) gewinnen lieB 139>. 

Tribenzo[6,d/]thiepin synthesis, 7, 587 Tribenzoxepins resolution, 7, 14 Tribenz[6,4/ oxepins synthesis, 7, 581... 

On irradiation, 3,4-dihydropyrene epoxide 475 undergoes a ring expansion, resulting in tribenzo[bcd]oxepine 476 (79T1059). 

An attempted synthesis of 9-methylnaphtho[crf]oxepine-2-one 494 by heterocyclization of 8-acetyl-1-naphthoic acid 491 (R = Me, R = H) has failed. In acidic medium or on heating acid 491 to 150°C, as well as under formation conditions for the acid chloride or ester from acid 491, 2-acetylacenaphthene-l-one 495 is obtained (79ZOR1562). A synthesis of tribenzo[c]oxepine derivatives 499 and 501 has been described as resulting from heterocyclization of the products of reduction (498) or oxidation (500) of 4-formyl-5-carboxyphenanthrene 497. The latter compound was obtained on ozonolysis of pyrene 496 [71JCS(C)729]. 

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