Successive Diene Addition and Dehydrogenation in Nitrobenzene Solution Without Isolation of the Hydroaromatic Intermediate

Benzoannellated Fenestranes Bearing para‐Terphenyl Units

“…The reaction was run in nitrobenzene under reflux to effectuate concomitant dehydrogenation. [44,45] At variance from comparable cases, however, aromatization did not take place in this case. Addition of manganese dioxide, which is known to dehydrogenate comparable Diels-Alder adducts, [46] did not help.…”

Halogenated Thiophenes as Precursors in the Preparation of Halogenated and Arylated Anthraquinones

“…A number of synthetic routes to arylated anthraquinones are known. It has been shown by E. Bergmann et al 6,7 that [4+2]-cycloaddition reactions of phenylbutadienes 2 with either 1,4-naphthoquinone (3a) or with p-benzoquinone (3b) give 1-phenylanthraquinone (4a) and 1,4-phenylanthraquinone (4b) (from 1,4-naphthoquinone) and 1,5-diphenylanthraquinone and 1,4,5,8-anthraquinone (from p-benzoquinone), respectively (Scheme 1). J. E. Gautrot et al 2a started from 1,4-dihydroxy-9,10-anthraquinone, which was transformed into its bistriflate 5 2b and subsequently subjected to coupling reaction with arylboronic acids (Scheme 2 Coupling reactions have also been carried out with 1-diazoanthraquinone, which were prepared from the corresponding 1-aminoanthraquinone.…”

Synthesis and Structure of a Longitudinally Twisted Hexacene

“…Why this is the case is not clear and made all the more curious by the fact that heating a mixture of 5 with 5,8‐dioxo‐5,8‐dihydronaphthalene‐1,4‐diyl diacetate ( 8 ) in nitrobenzene did form 7 , which was conveniently and cleanly precipitated from the reaction contents in 33 % yield by the addition of acetone (Scheme ). In addition, the in situ hydrolysis of the acetyl moieties was not expected either, but desirable and perhaps may be attributed to the high temperature and to the water formed during the course of the reaction . Next, using a procedure adapted from Lepage, phenyllithium was added to a suspension of 7 in dry THF and stirred for 24 hours.…”