Anthraquinone and anthrone series

Rao, N. Rama; Shah, Khizar Hussain; Венкатараман, К.

doi:10.1007/bf03172288

Cited by 6 publications

(6 citation statements)

References 18 publications

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“…Isopropanol was dried by distilling over magnesium turnings/I 2 under argon. t-Butylvinylketone and Phenyl vinyl ketone [11], 1,8-bis-p-toluenesulfonamide anthraquinone [12], 1,8 diaminoanthraquinone [12], and 1,8-diaminoanthracene [13] were prepared following literature procedure. 5 mL).…”

Section: Methodsmentioning

confidence: 99%

Synthesis, characterization, and cyclometalation studies of benzo[1,2-h: 5,4-h′]diquinolines with palladium and platinum

Young

Kaska

2011

Journal of Organometallic Chemistry

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Section: Methodsmentioning

confidence: 99%

Synthesis, characterization, and cyclometalation studies of benzo[1,2-h: 5,4-h′]diquinolines with palladium and platinum

Young

Kaska

2011

Journal of Organometallic Chemistry

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“…l,8-Bis(3'-methylisoalloxazin-10r-yl)naphthalene (5 and/ or 6): The synthesis started from 1,s-diaminonaphthalene which was treated with 2-fluoronitrobenzene (DMSO, potassium hydroxide, 4h, 50"C, under argon) to yield, 1,8-bis(2'-nitrophenylamino)naphthalene (22). By catalytic hydrogenation of 22 (Pdlcharcoal, acetic acid) 1,8-bis(2'-aminopheny1amino)naphthalene (23) was obtained.…”

Section: Arene-bridged Bis(isoal1oxazines): Syntheses and Propertiesmentioning

confidence: 99%

“…A structure analysis was achieved, however, for the third compound in the series of arene-spacered bis-(isoalloxazines), the 9,lO-dihydroanthracene analogue 26 (for crystallographic data see Experimental). In addition, the structure of 1,8-bis(2'-nitrophenylamino)naphthalene (22) has been solved; as was discussed above, 22 is a key precursor for the synthesis of 6, and its structure was of interest with regard to the interaction of large substituents with highly polar groups in the two 1,8-positions of naphthalene.…”

Section: X-ray Structure Analyses Of Compounds Relevant To Arene-spacmentioning

confidence: 99%

“…H 4.03,N 13.99;found C 65.81,H 4.02,N 13.87. (22): 22 crystallized from toluene as ruby needles (0.25 X 0.10 X 0.1 mm); C2ZH16N404; molecular mass: 400.4; triclinic space group P1 (No. 2, Intern.…”

Section: Iolo'-dimethyl[33](38) Isoalloxazinophane (4)mentioning

confidence: 99%

“…Evaporation of the solvent from the filtrate and crystallization of the residue from acetic acid yielded 120 mg (68%) of 29 as a brick-red crystalline powder, m. p. 250°C (dec.). -MS: mli (%) = 404 (100, M'), 403 (32), 320 (22), 319 (88), 318 (58).…”

Section: Io-(l'-anthry/~-3-methy/i~ou/loxazine (29)mentioning

confidence: 99%

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[3.3]Isoalloxazinophanes and Arene‐Bridged Bis(isoalloxazines): Syntheses, Characterizations and Properties Related to Intramolecular Interactions

et al. 1994

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In order to study the orientation and distance dependence of TC-TI interactions between flavins in various redox states, two approaches to bis(isoal1oxazine) model compounds are presented: The [3.3]isoalloxazinophanes 2 and 4 and the rigid single-bridged 1,8-naphthalene-and l$-anthracene-linked bis(isoal1oxazine) systems 6, 8 and 26 were synthesized, characterized, and studied by spectroscopic methods and cyclic voltammetry. The experimental data are discussed in comparison with "monomeric" isoalloxazines and flexible singlechain trimethylene-linked bis(isoal1oxazine) reference compounds. X-Ray structure analyses are reported for the 1,8-bis(isoalloxazinyl)-9,1O-dihydroanthracene 26 and for 22 as an example of 1,8-disubstituted naphthalenes with strongly polar substituents comparable to 6.One of the most important features in flavin chemistry is the ability of the isoalloxazine system to exist in three different stable redox states: the flavoquinone, the flavoseniiquinone radical and the flavohydroquinone. These redox states can be further modified by protonation or deprotonation, formation of hydrogen bonds or steric factors. For these reasons, the flavocoenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) play an essential role in biological processes as mediators between nicotinamide nucleotides as exclusive two-electron carriers and typical oneelectron carriers such as ferredoxin iron sulfur clusters or metalloporphyrins. It has also been postulated that in the active site of some enzymes (e. g. NADPH-cytochrome P4,,-reductase) two flavins act as a single redox-active unit [*].The quinhydrone-like association of oxidized and reduced flavins was first discussed by Kuhn and Strobele[31. Although the spectroscopic properties of semireduced flavin systems have been studied extensively since thenr41, the spatial arrangement favoring chargetransfer interactions and the exchange of redox equivalents by electron transfer is still a matter of controversial discussionc51. In the past, there have been some attempts to inimic these interactions by open-chain trimethylene-linked bis(isoalloxazines)[61. As a major disadvantage of such models, however, it must be realized that their steric structure due to the flexibility of the linking chain is not welldefined. Suitable model systems for determining the orientation and distance dependence of flavin-flavin interactions require clearly defined rigid geometries with sandwich-like flavin-flavin orientation as well as a controlled variation of interplanar distances by the choice of different spacer groups.With the intention to contribute to the understanding of flavin coenzyme functions we tried to synthesize models meeting these requirements. Results referring to flavin-flavin interactions are described in this paper; in the following papers we report on an analogous approach in the attempt to synthesize models for flavin interactions with nicotinamidec7I and quinones[*].Based on earlier extensive experiences of our group in using the "cyclophane concept...

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