Showing papers on "Fluorenone published in 1979"

Dye- and dicyanoanthracene-photosensitized oxygenations of sulphur compounds. Product selectivity

Abstract: Photo-oxygenation of vinyl sulphides sensitized either by dyes or by 9,10-dicyanoanthracene (DCA) gave products arising from oxidative cleavage of the double bond in closely similar ratios in each case; similarly, dye-photosensitized oxygenation of fluorenyl ethyl sulphide gave fluorenone, 1-hydroxy-9-fluorenone, 9-fluorenyl ethyl sulphoxide, and 9-fluorenyl ethyl sulphone as major products, while DCA-sensitized oxygenation gave the first three products in similar relative yields.

Hydrogen-bonding of cyclopentadithiophenones and fluorenone in trifluoroacetic-acid - study of the electronic absorption, h-1 and c-13 nuclear magnetic-resonance spectra

Abstract: The electronic absorption bands of cyclopentadithiophenones and fluorenone show large shifts towards longer wavelengths when the solvent is changed from cyclohexane to CF3CO2H. 1H and 13C n.m.r. spectra of these ketones in CDCl3 and CF3CO2H differ considerably. These observations point to strong hydrogen bond formation between the carbonyl oxygen atom and the solvent. Taking hydrogen bond formation into account by changing the core parameters of the oxygen atom, PPP calculations satisfactorily predict the bathochromic shifts of the electronic absorption bands. The calculated change in electron density at a particular carbon atom correlates well with the change in 1H and 13C n.m.r. chemical shifts as measured in CDCl3 and CF3CO2H.

Stereodynamische Charakterisierung von Fluorenon‐anilen

Abstract: Stereodynamic Characterization of Fluorenone Anils Topomerizations (or isomerization) of the azomethines 1–7 are characterized with respect to kinetic parameters and substituent dependence. The dynamic behaviour parallels that of other anils.

Chemical modification of polymers. XI. Photoreactive polymers from poly(vinylbenzyl chloride)

Abstract: Photocrosslinking has been observed in a number of polymers derived by chemical modification of poly(vinylbenzyl chloride). Included are polymers bearing pendant benzophenone, stilbazolium, fluorenone, carbazole, and sulfonylazido moieties. The synthesis and properties of these polymers are described.

Zur Bildung von Xylol-tricarbonylchrom (Dimethylbenchrotrenen) aus Di-n-butylether und Hexacarbonylchrom

Abstract: The reaction of fluorenone ethyleneketal (9), diphenic anhydride as well as of biphenyls such as4 with Cr(CO)6 in refluxing di-n-butylether (BE) gives dimethylbenchrotrenes [xylene-Cr(CO)3,7] which are also formed by refluxing pureBE with Cr(CO)6—although with much lower yields. Similarily, from di-n-pentylether and Cr(CO)6 isobutyl- and 1-methyl-3-propyl-benchrotrene (13 and14) were obtained, whilst from di-n-propyl- and-hexylether, resp., and Cr(CO)6 no benchrotrenes could be isolated.

Sulphur nitrides in organic chemistry. Part 5. The reaction of tetrasulphur tetranitride with oximes and imines

Abstract: The reaction of tetrasulphur tetranitride (N4S4)(1) with oximes (2a–d) and imines (3a and b) was carried out under refluxing condition in toluene. It was found that the N–O bond in benzophenone oxime (2a) or fluorenone oxime (2b) was cleaved by (1) to afford the corresponding imino-sulphides such as bis(diphenylmethyleneamino) sulphides (4) or bis(fluorenylideneamino) sulphides (7) together with benzophenone (5) and benzanilide (6), or fluorenone imine (3a), fluorenone (8), and fluorenylideneaminosulphenamide (9), respectively. The reaction of (1) with (3a) was carried out under the same conditions to give the expected bis(fluorenylideneamino) monosulphide (7a) together with the trisulphide (7b), (8), and (9). Similarly phenanthrenequinone monoimide (3b) afforded the bis(oxophenanthrenylideneamino) monosulphide (13) in 83% yield. From these results, it can be concluded that imines are probably an intermediate in the formation of the imino-sulphides (4) and (7). In contrast to (2a and b), cyclohexanone oxime (2c) afforded only large amounts of tarry materials. It was also found for the reaction with benzil monoxime (2d) that not only the N–O bond but also the C–C bond of (2d) was cleaved with (1) to afford benzamide (10) and benzonitrile (11) together with 3,4-diphenyl-1,2,5-thiadiazole (12).

Adducts of Group IVB radicals with sulphur-containing Diaryl ketones

Abstract: The hyperfine splitting constants for the paramagnetic adducts of ·MR3 radicals (M = Si, Ge, or Sn) with some dithienyl and bisthienothienyl ketones, benzophenone, and fluorenone are reported and compared with those for the corresponding diarylhydroxymethyl radicals. From the results, and with the aid of INDO calculations, it has been found that in the former derivatives the O–M bond eclipses the 2Pz orbital of the carbonyl atom, at variance with the hydrogen adducts, which exhibit practically planar conformations. Barriers to rotation of the OH group in benzophenone and fluorenone derivatives have been determined from the temperature dependence of the aHOH splitting and are 5.1 and 6.5 kcal mol–1, respectively.

Oxidation of fluorenes by ammonium meta vanadate—a kinetic study

Abstract: The oxidation of fluorene by vanadium(V) in aqueous acetic acid containing sulfuric acid (1.0M) at 50°C produces fluorenone and 2-hydroxy diphenyl 2′-carboxaldehyde. The order with respect to each reactant is found to be 1. The order dependence on sulfuric acid concentration is 4, indicating that V(OH)23+ could be the active species. An increase in the acetic acid percentage in the solvent medium increases the rate of the reaction. The effect of solvent variation has been discussed in the light of the acidity function and the polarity of the medium. The effect of substituents on the rate has been studied for seven substituted fluorenes, and a linear relationship exists between log k versus σ values with the slope ρ = -3.2. A small isotope effect is observed for the oxidation of the parent compound (kH/kD = 1.2). The effect of temperature on the rate of the reaction has been studied, and the activation parameters are discussed. A mechanism involving the rate-limiting formation of a cation-radical intermediate is proposed.

The Similarity between the π,π* Absorption Spectra of 1-Indenone and 1,2-Naphthoquinone

Abstract: The π,π* absorption spectrum and its solvent effect of 2-methyl-1-indenone have been found to be similar to those of 1,2-naphthoquinone. This fact is discussed on the basis of the results calculated using the P-P-P method. The similarity of the calculated π-electronic structures in the low-energy π,π* singlet states between 1-indenone and 1,2-naphthoquinone is not so good as that between fluorenone and 9,10-phenanthrenequinone.

Sur les dérivés de la fluorénone. IX. La (pyridyl‐2)‐3‐fluorénone, la méthyl‐2‐(pyridyl‐2)‐3‐fluorénone et la méthyl‐3‐(pyridyl‐2)‐3‐fluorénone

Abstract: Fluorenone Derivatives. IX. 3-(Pyrid-2-yl)-fluorenone, 2-methyl-3-(pyrid-2-yl)-fluorenone, and 2-(3-methyl-pyrid-2-yl)fluorenone Unsuccessful attempts to synthesize an aza-cis-fluorenacene system starting from 2-aza-chalcone or 6-methyl-2-aza-chalcone led to the title compounds.

Oxidation of fluorenes by ammonium meta vanadate - a kinetic study

Abstract: The oxidation of fluorene by vanadium(V) in aqueous acetic acid containing sulfuric acid (1.0M) at 50°C produces fluorenone and 2-hydroxy diphenyl 2′-carboxaldehyde. The order with respect to each reactant is found to be 1. The order dependence on sulfuric acid concentration is 4, indicating that V(OH)23+ could be the active species. An increase in the acetic acid percentage in the solvent medium increases the rate of the reaction. The effect of solvent variation has been discussed in the light of the acidity function and the polarity of the medium. The effect of substituents on the rate has been studied for seven substituted fluorenes, and a linear relationship exists between log k versus σ values with the slope ρ = -3.2. A small isotope effect is observed for the oxidation of the parent compound (kH/kD = 1.2). The effect of temperature on the rate of the reaction has been studied, and the activation parameters are discussed. A mechanism involving the rate-limiting formation of a cation-radical intermediate is proposed.