Benzophenone and its derivatives

Kawaguchi, M., R. Ito, N. Endo, et al. 2006. Stir bar sorptive extraction and thermal desorption-gas chromatography-mass spectrometry for trace analysis of benzophenone and its derivatives in water sample. Anal. Chim. Acta 557 272-277. 

Oarboxy-arsinie Adds and their Derivatives—Nitro-, Amino- and Hydroxy-carboxyarylarsinic Acids—Condensation Products of Dichloro-p-arsino-benzoyl (boride with Amino-adds and Bligher Alcohols —. senatod Benza ide and its Derivatives, Arsenated Benzophenone and its Derivatives—Arsenated Acetophenone Derivatives. 

The nanosecond-picosecond two-color two-laser flash photolysis method is also useful to study the excited state of radicals, that is, the D, state. We applied nanosecond-picosecond two-color two-laser flash photolysis to detect the absorption and fluorescence spectra of the ketyl radical of benzophenone and its derivatives (BPH and BPDH ) in the excited state in the UV-visible region [111], since BPH and BPDH are well investigated radicals in various fields. Since BPH and BPDH are generated from irreversible ways, such as photoionization, we employed a streak camera to realize the single-shot detection of these intermediates. 

Besides only as green reaction media, ionic liquids as dual green solvents and catalysts are also widely used in acylation reactions, especially C-acylation. Benzophenone and its derivatives are important fine chemicals or intermediates in dyes, pharmaceuticals, and other chemical industries. Li et al. have studied the Friedel-Crafts acylation reactions using ionic liquids like BMlMCl-FeClj, BMIMCI-AICI3, and BMIMCl-ZnCl as dual catalyst-solvent to synthesize benzophenone and its derivatives. They found that BMIMCl-FeCl3 showed much higher catalytic activity than that observed for the other two ionic liquids, and in conventional organic... 

This reaction was reported for the benzophenone photosensitized degradation of polypropylene (92),polystyrene (95), poly(vinyl alcohol) (94),polyisoprene (95,96),polyurethane (97) and polyadenylic acid (98) In solid state benzophenone also produce an extensive crosslinking of polyethylene (99-105) It has also been found that benzophenone and its derivatives caused an initial rapid oxidation,increasing with ketone concentration (70) Currently the relative importance of singlet oxygen formation in energy transfer reaction between excited benzophenone and molecular oxygen is discussed (92,104) ... 

The crosslinking process is specially extensive in the solid state in the presence of external initiators, photo-initiators and sensitizers [Refs. 40, 362, 393, 489, 503, 505, 632]. For example the decomposition of di-tert-butylperoxalate in polypropylene in the absence of oxygen gives a tightly crosslinked polymer. When the decomposition is carried out in the presence of oxygen, the polymer instead softens [405]. Benzophenone and its derivatives induce the crosslinking of solid polyethylene on exposure to UV light [Refs. 138, 469, 470, 665]. Table 4 shows the influence of various photosensitizers on the amounts of the gel fraction produced in solid polyethylene exposed to UV radiation. 

The photochemical aspects of carbonyl photochemistry remain important subjects of research. Wagner and Thomas have used CIDNP to elucidate radical formation from a,a,a-trifluoroacetophenone. Irradiation of benzophenone and its derivatives in the presence of molecules with abstractable hydrogen atoms can give rise to intensely fluorescent compounds. This effect may interfere with the observation of nanosecond-domain kinetics.Quantum yields and kinetic isotope effects in nanosecond flash studies of the reduction of benzophenone by aliphatic amines have been measured by Inbar et Rate constant data are given in Tables 13 and 14. Winnik and Maharaj have studied the reaction of benzophenone with n-alkanes through hexane to hexatriacontane is 3.9 0.2kcal for all chain lengths.The effects of substituents on the benzophenone on these reactions have also been examined. The reactions of phenylacetophenone when used as polymerization initiator have been reviewed by Merlin and Fouassier. ... 

Benzophenone and its derivatives are also affected by substituents. Thus, 4 -(4 -methylphenylthio)-benzophenone,... 

The chemistry involved in LfV-curable resin systems has been extensively investigated and thoroughly surveyed [88-94]. LfV-radiation polymerization, is in principle, completely analogous to the conventional addition polymerization. A photoinitiator is used in UV polymerization. Its function is the same as the free-radical initiator. A conventional initiator possesses a thermally labile bond which is cleaved to form free-radical species, but the photoinitiator has a bond which breaks upon absorption of radiant energy. Benzoin ethers, benzyldialkyl ketals, benzophenone, and acetophenone derivatives are the important LfV-photoinitiators [95-99]. 

Note The ion series m/z 51, 77, 105 is a reliable indicator for benzoyl substructures, e.g., from benzaldehyde, benzoic acid and its derivatives, acetophenone, benzophenone etc. Different from benzylic compounds, the peaks at m/z 39, 65, and 91 are almost absent. If a peak at m/z 105 and the complete series m/z 39, 51, 65, 77, 91 are present, this strongly points towards the composition [CgHg]", and thus to phenylalkanes. In case of doubt, HR-MS is the method of choice for their differentiation. 

Type 2 initiators are bimolecular systems and consist of a photosensitizer and a hydrogen donor. The most well known system is benzophenone/tertiary amine. Because of the relatively weak absorption of benzophenone at 360 nm the efficiency of this system is rather low. A more efficient aromatic ketone is thioxanthone (TX) and its derivatives simply because of the increased at the exposure wave length. 

Cosmetic products that are photoallergenic include fragrances, such as musk ambrette and 6-methylcoumarin, and sunscreens (e.g., para-aminobenzoic acid and its derivatives, benzophenones, dibenzoylmethanes).17 Oil of bergamot, previously a popular ingredient in fragrances, has now been eliminated from most perfumes due to its phototoxic properties.24... 

When the 7-enolate anion of 2-benzylperhydropyrido[l,2-a]pyrazin-6-one, generated with LDA or BuLi in THF, was treated with benzophenone and its 4,4 -difluoro derivative, a mixture of diastereomeric cis- and trans-1-diarylhydroxymethyl derivatives was formed, which was dehydrated with 48% aqueous HBr (93JOC690). 

Several molecules which can undergo intramolecular proton transfer in the excited state have been found to be unusually photostable. Thus, for example, 2-hydroxybenzophenone is used as a photostabilizer in polymers while benzophenone itself is photoactive (Kysel, 1969). In crystalline 2-(2 -hydroxyphenyl)benzothiazole and its derivatives [3] a proton is transferred in the excited state from an... 

Data on the photochemical stability and stabilizing action of HB s, benzotriazoles, and related compounds have been reported on several occasions (6,9,70,71,7,82,87). In order to be a good stabilizer, it is not sufficient that a compound does not decompose if dissolved for example, in a plastic, it is equally important that it does not act as a sensitizer. Investigations on the sensitizing action of HB s compared to that of benzophenone and nonchelated derivatives are, therefore, of interest. Such studies are Included by Lamola (8), A. Heller (80), and Hammond (74). Cls-trans isomerization of piperylene (1,3-pentadiene) in benzene is easily sensitized by benzophenone via triplet transfer... 

From B. Pandey s research group comes a straightforward photochemical method for the synthesis of spirocyclic compounds. An intramolecular hydrogen abstraction by an excited enone group is followed by radical combination. It is remarkable that no product arising from photoenolization and subsequent cyclization was observed. This is usually observed in ortho-alkyl substituted benzophenone and acetophenone derivatives. 

Phosphazene and its derivatives have been used as bases to catalyze the synthesis of highly substituted benzofurans. Krause and co-workers used phosphazenes in a key step of their total synthesis of amurensin H, an antiinflammatory compound. Treatment of a highly substituted benzophenone precursor with P4- Bu in benzene gave amuresin H after deprotection of the methyl esters with boron tribromide. 

Electron nuclear double resonance is a powerful tool for the study of the electronic structure of triplet states because of its high precision. ENDOR linewidths can be as narrow as 10 kHz, which represents an increase in resolution of better than six orders of magnitude over that which can be obtained optically. The technique is particularly useful when combined with hf methods owing to the first-order nature of the hyperfine interaction in the presence of a field. Although such experiments are difficult, the information obtained is unique. Accordingly, the hf EPR (or ODMR) spectrometer has been modified for ENDOR operation in several laboratories. In order to illustrate the power of the method, we discuss here some recent optically detected hf ENDOR experiments on (njr ) benzophenone and its iso-topically labeled derivatives (Brode and Pratt, 1977, 1978a,b). The results, although incomplete, show considerable promise for the ultimate determination of the complete spin distribution in this prototype triplet state. 

---