The Chemistry of Fluorene and its Derivatives.

Rieveschl, George; Ray, Francis Earl

doi:10.1021/cr60075a002

Cited by 36 publications

(14 citation statements)

References 137 publications

(227 reference statements)

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“…For example, fluorene, from which fluorenone is a known oxidation product, is commonly present in excess of 1% in coal tar mixtures. 9-fluorenone, with its carbonyl group on a central carbon between aromatic rings, readily forms oximes, such as 9-fluorenone oxime [1]. The seven heteroatomic and heterocyclic aromatic compounds investigated herein are only some examples of compounds of potential interest, and for which few thermodynamic property measurements are available.…”

Section: Introductionmentioning

confidence: 99%

Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

Goldfarb

Suuberg

2010

The Journal of Chemical Thermodynamics

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The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) grams⊕mol −1 were measured over the temperature range of (301 to 486) Kelvin using the isothermal Knudsen effusion technique. The compounds measured include: anthraquinone, 9-fluorenone, 9-fluorenone oxime, phenoxazine, phenoxathiin and 9H-pyrido [3,4-b]indole. These solid-state sublimation measurements provided values that are compared to vapor pressures of parent aromatic compounds (anthracene and fluorene) and to others with substituent groups in order to examine the effects of alcohol, ketone, pyridine, and pyrrole functionality on this property. The enthalpies and entropies of sublimation for each compound were determined from the Clausius-Clapeyron equation. Though there is no consistent trend in terms of the effects of substitutions on changes in the enthalpy or entropy of sublimation, we note that the prevalence of enthalpic or entropic driving forces on vapor pressure depend on molecule-specific factors and not merely molecular weight of the substituents.

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Section: Introductionmentioning

confidence: 99%

Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

Goldfarb

Suuberg

2010

The Journal of Chemical Thermodynamics

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“…Classic synthetic approaches to phenanthrenes were developed, for example, by Pschorr and Haworth 16. Phenanthrenes have been also prepared by oxidative cyclizations of cis ‐stilbene derivatives 17.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 9‐Aryl‐9,10‐dihydrophenanthrenes by Domino [3+3] Annulation/Ring‐Opening/Friedel–Crafts Alkylation Reactions of 1,3‐Bis(trimethylsilyloxy)‐1,3‐butadienes with 3‐Aroyl‐5‐aryl‐4,5‐dihydrofurans

et al. 2010

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“…Some syntheses of fluorenones employ fluorene, 11 benzophenone, 12 or hexahydrofluorenone 13a precursors. Unfortunately, these procedures either give isomeric mixtures, are low yielding or offer limited access to certain isomers.…”

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confidence: 99%

An Efficient Synthesis of Dihydroxyfluorenones via in Situ Pd(0)-Catalyzed Cross-Coupling

Ciske¹,

Jones²

1998

Synthesis

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All six dimethoxyfluorenones 6a-f and dihydroxyfluorenones 7a-f , wherein substitution occurs at only one aromatic ring, were conveniently prepared by palladium(0)-catalyzed cross-coupling reactions of aryl bromides/triflates 2a-e with in situ generated arylboranes, derived from o -bromobenzamide 1a and o -bromophenyloxazoline 1b .Fluorenone derivatives are known to display a variety of biological activities. 1-3 Also, several methoxy and hydroxyfluorenone derivatives are natural products whose syntheses have recently been described. [4][5][6][7][8][9] As part of our investigation into the protein kinase inhibitory activity of substituted fluorenones, 10 we desired a convenient method for preparing all possible dihydroxy regioisomers in which substitution occurs on only one aromatic ring of the fluorenone nucleus.Some syntheses of fluorenones employ fluorene, 11 benzophenone, 12 or hexahydrofluorenone 13a precursors. Unfortunately, these procedures either give isomeric mixtures, are low yielding or offer limited access to certain isomers. Increased accessibility of substituted biphenyls through numerous cross-coupling techniques makes the intramolecular acylation reactions of biphenyl carboxylic acids 11 and biphenyl amides 14 an attractive approach to fluorenones. Of note are the recently reported in situ Suzuki cross-coupling methods which obviate the need for isolation of boronic acid intermediates. 15 Furthermore, the respective cyclization chemistries of biaryl-2-carboxylic acids and biaryl-2-carboxamides, the classical and anionic equivalent of the Friedel-Crafts reaction, are complementary and enable the preparation of a complete isomeric set. In an effort to obtain all possible dihydroxyfluorenone regioisomers 7a-f , we have employed and here report a convenient synthetic approach utilizing, 1) an efficient in situ generation and Pd(0)-catalyzed crosscoupling of aryl boranes to prepare substituted biaryls; 2) regiospecific remote aromatic metalation cyclization; and 3) a complementary Friedel-Crafts acylation cyclization.Thus, 2-bromo-N , N -diethylbenzamide (1a) (Scheme 1) undergoes lithium-halogen exchange and boronation at the 2-position. Treatment of the boronate with dimethoxyaryl bromides and aryl triflates 2a-e under modified in situ Suzuki conditions gave the biarylamides 3a-e . Intramolecular cyclization occurs when 3a-e react with LDA in a remote metalation process as described by Snieckus. 14 The five dimethoxyfluorenone regioisomers 6a-e thus formed are easily demethylated with refluxing HBr/AcOH to give dihydroxyfluorenones 7a-e in good yield.In order to obtain the sixth regioisomer 7f , we employed the same in situ coupling procedure using 2a and oxazoline 1b as a masked carboxylic acid (Scheme 2). Acid hydrolysis of the ring-opened 16 intermediate 4 gave biaryl-2-benzoic acid 5 which underwent normal Friedel-Crafts cyclization to regioselectively provide 2,3-dimethoxyfluoren-9-one (6f) in high yield. 17 Fluorenone 6f cannot be prepared by the anionic equivalent route since the more acidic o...

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The Chemistry of Fluorene and its Derivatives.

Cited by 36 publications

References 137 publications

Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

Synthesis of 9‐Aryl‐9,10‐dihydrophenanthrenes by Domino [3+3] Annulation/Ring‐Opening/Friedel–Crafts Alkylation Reactions of 1,3‐Bis(trimethylsilyloxy)‐1,3‐butadienes with 3‐Aroyl‐5‐aryl‐4,5‐dihydrofurans

An Efficient Synthesis of Dihydroxyfluorenones via in Situ Pd(0)-Catalyzed Cross-Coupling

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