- A Five Fused Ring Non-benzenoid Quinone Containing a Seven-membered Ring: Synthesis and Properties of Cycloheptaceanthrylene-5,8-dione and 1,2-Dihydrocycloheptaceanthrylene-5,8-dione
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Cycloheptaceanthrylene-5,8-dione 16 and 1,2-dihydrocycloheptaceanthrylene-5,8-dione 15 have both been synthesized in four steps from aceanthrene 9 in 8 and 7 percent overall yield, respectively.On the basis of their reduction potentials, the compound 16 was shown to be an annulenedione with a higher reduction potential than the isomeric cyclopentapleiadene-5,10-dione 2.An unsuccessful attempt to synthesize cycloheptaceanthrylene 21 as well as the efficient synthesis of aceanthrene 9 from anthracene is also described.
- Morita, Kiyokazu,Aida, Takashi,Morinaga, Kennichi,Tsunetsugu, Josuke
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- Synthesis and spectroscopy of nitroaceanthrylenes and nitroaceanthrenes
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The syntheses of nine mononitro derivatives of aceanthrylene (1) and nine mononitro derivatives of aceanthrene (2) are described.In addition to 1 and 2, 1,2,6,10b-tetrahydroaceanthrylene (3), 6,10b-dihydro-2(1H)-aceanthrylenone (5), 1(2H)-aceanthrylenone (4) and 2(1H)-aceanthrylenone (8) were also used as starting materials.The resulting nitroaceanthrylenes and nitroaceanthrenes were characterized by their 1H-NMR, 13C-NMR, UV-VIS, IR and mass spectra.The conformation of the nitro group and the interaction between the nitro group and the aromatic system are discussed.In 2-nitroaceanthrylene (1b), the nitro group interacts exceptionally well with the aromatic nucleus.The 3-, 4-, 8- and 9-nitro derivatives of 1 and 2 display all the characteristics of normally conjugated planar nitroaromatic compounds.In the remaining nitro derivatives of 1 and 2, conjugation is diminished owing to steric interactions with nearby protons.The order of decreasing conjugation and increasing twist angle is 5-nitro > 7-nitro > 6-nitro > 10-nitro.The twist angle of the nitro group was calculated using semi-empirical SCF methods PM3 and AM1.Although the values obtained by these methods deviate substantially, they both give the same order of increasing twist angles as the spectroscopically derived order.
- Mulder, Patrick P. J.,Boerrigter, Jos Olde,Boere, Ben B.,Zuilhof, Han,Erkelens, Cornelis,et al.
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- On the Neophyl-like Rearrangement of 2-(9-Anthryl)ethyl Radicals
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The 1,2 migration of the aryl group in deuterated 2-(9-anthryl)ethyl and 2-ethyl radicals has been studied by product analyses with the use of the competing reaction ArCH2CD2(.) + Bu3SnH.The rearrangement was so fast that equimolecular mixtures of the unrearranged (ArCH2CD2H) and rearranged (ArCD2CH3) hydrocarbons were obtained even in the presence of a large excess of Bu3SnH (ca. 1 M).The lower limit for the rate constant of the intramolecular process, kr, could be estimated as 5E7 s-1.Ab initio MO computations, performed on the2-phenylethyl radical, chosen as the simplest model for 2-arylethyls, showed that the aryl migration may occur either through the intermediacy of the spirocyclopropanecyclohexadienyl radical or via a three-membered transition state having geometrical and electronic properties different from those of the potential cyclic intermediate.The spectroscopic and chemical results are consistent with the rearrangement taking place via the intermediacy of spirocyclopropane radicals, which, as both thermochemical calculations and experimental evidence indicate, are characterized by a considerable thermodynamic stability.In fact, the spiro radicals could be easily observed by EPR spectroscopy when generated by hydrogen abstraction from the corresponding cyclic hydrocarbons, and the kinetics of their decay could be studied.The diamagnetic dimer of the 9,10-dihydro-10-spiro-9-yl radical was also isolated, and its structure determined by X-ray crystallographic analysis.The same cyclized radicals were detected when producing the two arylethyl radicals within the EPR cavity.Chemical generation of the 2-(9-anthryl)ethyl radical in the presence of low concentrations of hydrogen donors led to the isolation of remarkable amounts of the dimer of its cyclic structural isomer.These results provide evidence that the 2-anthrylethyl radical and the phenyl-substituted analogue may exist in either of the two rapidly equilibrating open-chain and cyclized forms and react preferentially in one of them depending on the experimental conditions.
- Leardini, Rino,Nanni, Daniele,Pedulli, Gian Franco,Tundo, Antonio,Zanardi, Giuseppe,et al.
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p. 7723 - 7732
(2007/10/02)
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- THE USE OF A DOUBLE WOLFF-KISHNER REDUCTION IN THE PREPARATION OF ACEANTHRENE AND ACEANTHRYLENE
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Aceanthrene (2) and aceanthrylene (1) are easily prepared in high yield from aceanthrenequinone (3) by means of a double Wolff-Kishner reduction.
- Boerrigter, Jos C. Olde,Mulder, Patrick P. J.,Gen, Arne van der,Mohn, Georges R.,Cornelisse, Jan,Lugtenburg, Johan
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