Fluoren-2-ones

Intramolecular arylations can also be carried out photochemically. Huisgen and Zahler (1963 a) prepared fluoren-9-one by irradiation of benzophenone-diazonium salts in dilute sulfuric acid. The classical Pschorr synthesis of phenanthrene-9-carb-... 

Degradation by Mycobacterium sp. strain PYR-1 involves dioxygenation at both the 1,2-, and 7, 8-positions, producing after ring fission fluorene-9-one (Figure 8.13a), or acenaphthene-7-one (Figure 8.13b) (Kelley et al. 1993). In a strain of Alcaligenes denitriflcans, acenaphthene-7-oneis further... 

Monooxygenases. Under nonlignolytic conditions, arene monooxygenase and epoxide hydrolase systems may function to produce trani-dihydrodiols. Hydrogen abstraction mediated by the lipid peroxidase system may operate, for example, in the formation of fluorene-9-one from fluorene by Ph. chrysosporium (Bogan et al. 1996). 

Whereas plausible fungal metabolites from anthracene, acenaphthylene, fluorene, and benz[fl]anthracene—anthracene-9,10-quinone, acenaphthene-9,10-dione, fluorene-9-one, and benz[fl]anthracene-7,12-quinone—were found transiently in compost-amended soil, these were formed even in sterile controls by abiotic reactions (Wischmann and Steinhart 1997). 

More recently, it was shown by List et al. [293-296] and later by Moses et al. [246] that the green emission of the PFs is due to fluoren-9-one defects in the polymer chain. This was confirmed by comparison of PL films annealed in an inert atmosphere and in air a progressive additional band in the green region was observed on annealing in air (Figure 2.12) [246],... 

The chemistry of reaction of the highly reactive l-trimethylsilylcyclopropan[fc]naph-thalen-l-ide anion (126) with electrophiles has been explored.The anion can be trapped as the 1-methyl-1-trimethylsilyl derivative (128) [along with some (121) and (124)] when generated from (129) by action of Bu 0 -THF in the presence of iodomethane. If (126) is formed by action of H0 -H20 on (129) it is converted quantitatively into cyclopropanaphthalene (121) but can be trapped by carbonyl compounds such as benzophenone, fluoren-9-one, or 4-(dimethylamino)benzaldehyde. 

A -tetramethylethylenediamine). " Differences in the ability of [Ru(bpy)3], [Ru(bpz)3] and ci5-[Ru(bpy)2Cl2] to photosensitize DNA damage have been assessed. " The complexes [Ru(bpy)2L] and [Ru(phen)2L] (L = Schiff bases or phenylhydrazones derived form 4,5-diaza-fluoren-9-one) have been prepared it is proposed that their modes of binding to DNA involve electrostatic interactions, and nonintercalative and intercalative modes depending on the overall shape of each complex. Changes to the NMR spectra of A,A- and A,A-[(4,4 -... 

For ketones in which a CH2 group is replaced by a C=0, one adds the suffix one. For example, 9H-fluorene (XXII) becomes 9//-fluoren-9-one or 9-fluorenone (XXIII). 

For an organic compound (Q) in dipolar aprotic solvents, the half-wave potential ( 1/2) of the first reduction step tends to shift to the positive direction with an increase in solvent Lewis acidity (i.e. acceptor number). This is because, for the redox couple Q/Q, the reduced fonn (Q ) is energetically more stabilized than the oxidized fonn (Q) with increasing solvent acidity. The positive shift in E1/2 with solvent acceptor number has been observed with quinones [57 b], benzophenone [57 a, c] and anthracene [57 c], With fullerene (C60), the positive shift in E1/2 with solvent acidity parameter, ET, has been observed for the reductions of C60 to Qo, Qo to Clo, and Cf)0 to Cli, [54c], However, the positive shift in E1/2 is not apparent if the charge in Q is highly delocalized, as in the cases of perylene and fluoren-9-one [57 c]. 

A mixture of 3-methyl-97/-fluoren-9-one (79) [prepared from 2-aminophenyl-4-tolyl ketone (78) f217 2201 5.82g, 30mmol)],NBS (5.34g, 30mmol), and (BzO)2 (0.5 mg, 2.1 mmol) in CC14 (50mL) was stirred at rt for 2h, then refluxed for 2h. The hot soln was filtered and washed with hot CC14 until the solid became almost colorless. The yellow crystals (6.71 g) obtained from the concentrated filtrate (80 mL) were filtered and washed with cold CCl4(5mL). This crude product 80 contained 79 (ca. 5%) and the dibromo... 

Perfluoro-9//-fluoren-9-one reacts with sodium methoxide to give hcplafluoro-6-mcthoxy-9//-fluoren-9-one (49).109,110... 

Fluoren-9-one In a Pyrex matrix adapted to a Synthewave 402 monomode reactor, fluorene 1 (2 mmol, 0.332 g) was added to the KMn04-alumina mixture (6 mmol, 4.74 g). After 5 min of mechanical stirring, the mixture was irradiated (under stirring) at 150 W for 10 min. At the end of exposure to microwaves, the mixture was cooled to room temperature and eluted with diethyl ether (50 mL). After filtration and solvent removal, the crude product was identified by comparison (GC and NMR) with an authentic sample. 

Polycarbosilanes with the structure [SiR2—C=C—Z—C=C] (R2SiI 2,3,4,5-tetraphenyl-l-sila-2,4-cyclopentadiene Z 1,4-benzene, 4,4 -biphenyl, 9,10-anthracene, 2,7-fluorene and 2,6-pyridine, 6,6 -bipyridine, 2,5-thiophene, 2,6-p-dimethylaminonitrobenzene, 2,6-p-nitroaniline, 2,6-p-nitrophenol and 2,7-fluoren-9-one) were prepared by the reaction of l,l-diethynyl-2,3,4,5-tetraphenyl-l-sila-2,4-cyclopentadiene with the appropriate (hetero)aromatic dibromide or diiodide in the presence of [(PPh3)2PdCl2] and Cul182 (equation 69). 

The C-H transformation of imines via palladacycles has recently provided a novel synthesis of fluoren-9-ones [4], This high yielding synthesis is achieved by migration of palladium from an aryl position to an imidoyl position via C-H activation of the imine moiety, followed by intramolecular arylation (Scheme 2). 

Scheme 5. Mechanistic pathway for C-H activation of imines synthesis of fluoren-9-ones.

Under similar conditions, even benzylic C-H bonds of some hydrocarbons (xanthene and fluorene) are converted to the ketones (e.g., fluoren-9-one). Notwithstanding the parallel activities of the two catalysts, different mechanisms were tentatively proposed (277-279). Thus, for R.UC0AI-LDH-CO3, it was postulated that the presence of Co in the structure facilitated the formation of high-valent Ru(V)=0 species. In contrast, for the Ru-HAP catalyst, it was proposed that after coordination of the reactant to Ru as an alcoholate, the carbonyl compound was eliminated, leaving a Ru-H compound, which in a next step is reoxidized by O2. The basic nature of the HAP (or LDH) support may actually favor the latter route, with formation of an alcoholate. Filtration tests and elemental analyses confirm the stability of the supported species in both catalysts. 

Onychine (135) was first described as a natural product in 1976, when its isolation from Onychopetalum amazonicum (Annonaceae) was reported (83), and its structure was given as 4-methyl-l-azafluoren-9-one (158) on the basis of elemental analysis and high-resolution MS, as well as UV, IR, and H-NMR spectra. As in all the azafluorenone alkaloids discovered to date, the complex UV spectrum is reminiscent of that of fluoren-9-one, and the H-NMR spectrum clearly indicates the presence of a 2,3-disubstituted 4-methylpyridine moiety. The immediate conclusion, therefore, is that onychine is either l-methyl-4-azafluoren-9-one (135) or 4-methyl-l-azafluoren-9-one (158), which is supported by the spectral properties of the secondary alcohol obtained by reduction of the ketone group and of the acetylation and hydrogenolysis products of this... 

Table 4 References to unsubstituted diazafluorenes and diaza-fluoren-9-ones.

Tilorone hydrochloride, 2,7—bis [2-(diethylamine) ethoxy]-9H-fluorene-9-one dihydrochloride, is an orange solid which is highly water soluble at neutral and acidic pH. The compound is anhydrous and melts between 234-234.5 °C with decomposition. The molecular weight is 483.47. Tilorone-HC1 has an intense absorption band at 270 nm in water. The pKa of the amine functions are 8.64 and 9.27, respectively the compound is stable in acid or base. The synthesis of tilorone hydrochloride was outlined by Andrews et al.10), and Gaur and Wacker15). 

Alkyl-substituted nitrated fluorene-9-ones were synthesized with the expectation of improved solubility and lowered toxicity (Loutfy and Ong, 1984 Loutfy et al., 1984 Ong et al., 1985). These showed improved solubility and somewhat improved mobilities compared to TNF. Studies of dual-layer photoreceptors prepared with (4-H-butoxycaibonyl-9-fluorenylidene)malonitrile transport layers have been described by Loutfy et al. (1984) and Murti et al. (1987). Low-field trapping was observed. The mobilities of this molecule in a polyester (PE) have been described by Borsenberger et al. (1990) and Borsenberger and Bassler (1991a). A transport layer with this molecule pendant lias been prepared and used with a TiOPc generation layer (Sim et all., 1996). A very significant residual potential was observed. For reasons that are not well understood, this is a common observation for dual-layer photoreceptors prepared with acceptor doped transport layers. The residual potential usually increases with cycling such that the useful process lifetime is limited. 

Jaworski [92] has found that E° of perylene and fluoren-9-one are independent of the acceptor number, as opposed to formal potentials of anthracene and benzo-quinone, which exhibit a linear dependence on the ACN of the used solvents. The... 

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