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PubMed1987

Determination of the agonist-antagonist anxiolytic agent 6-(2-chlorophenyl)-4-hydroxy-4H-imidazo[1,5-a]-[1,4]benzodiazepine- 3-carboxamide and its benzophenone carboxylic acid metabolite in plasma by high-performance liquid chromatography.

A rapid, sensitive and selective high-performance liquid chromatographic (HPLC) assay was developed for the determination of 6-(2-chlorophenyl)-4-hydroxy-4H-imidazo[1,5-a]-[1,4]benzodiazepine- 3-carboxamide (I) and its benzophenone carboxylic acid metabolite, 1-[2-(2-chlorobenzoyl)phenyl]-4-(aminocarbonyl)-1H-imidazole-5-car boxylic acid (II) in plasma. The assay involves the extraction of both compounds into benzene from buffered plasma (pH 5.4) and subsequent analysis by reversed-phase HPLC. The overall recovery of I and II is 98.3 +/- 9.4 and 59.7 +/- 15.7% for dog plasma, 86.0 +/- 14.7 and 52.8 +/- 15.1% for rat plasma and 98.1 +/- 9.3 and 66.9 +/- 18.0% for human plasma, respectively. The sensitivity limit of the assay for I and II is 20.0 and 40.0 ng/ml of plasma using ultraviolet detection at 254 nm. The assay was used in studies in dog and rat.

Administration, Oral↗
PubMedDate not supplied

Structure and chemotherapeutical activity of a polyisoprenylated benzophenone from the stem bark of Garcinia huillensis.

The stem bark of Garcinia huillensis grown in Zaïre and used in central-African traditional medicine has been subjected to a bioassay-guided fractionation. The chemotherapeutically active petroleum ether extract afforded fatty acids, aliphatic alcohols, triterpenes and a polyisoprenylated benzophenone, which was identified as garcinol, also named camboginol. This compound has been shown to exhibit chemotherapeutical activity gram-positive and gram-negative cocci, mycobacteria and fungi. On the other hand garcinol has been found to be inactive against gram-negative enteric bacilli, yeasts and viruses.

Antiviral Agents↗
PubMed2005

Bimetallic isopropoxides M[Al(OC(3)H(i)(7))(4)](3) (M = Pr, Nd)--catalyzed reduction of 2-octanone and benzophenone.

Bimetallic alkoxides of praseodymium and neodymium with aluminum, viz., M[Al(OC(3)H(i)(7))(4)](3), where M = Pr(III)/Nd(III), have been used as catalysts in Meerwein-Ponndorf-Verley (MPV) reduction of 2-octanone and benzophenone in isopropanol to give their corresponding secondary alcohols. The reduction of ketones is investigated by following the absorption spectra involving 4f-4f transitions. During the MPV reduction the oscillator strengths (P) and the Judd-Ofelt intensity (T(lambda), lambda = 2,4,6) parameters corresponding to each 4f-4f band (H43-->D21, H43-->P03, H43-->P13, and H43-->P23 in praseodymium, and I9/24-->F3/24, I9/24-->F5/24, I9/24-->F7/24, I9/24-->G5/24, and I9/24-->G7/24 in neodymium alkoxides) at different time intervals have also been calculated and used in the determination of rates. Rates were calculated in terms of complexation of ketone and isopropanol with M[Al(OC(3)H(i)(7))(4)](3) during the MPV reaction, from the changes in both absorbance and oscillator strength with time, and were found to be comparable, verifying the Judd-Ofelt theory. The stronger oxyphilicity of Pr(III) and Nd(III) in M[Al(OC(3)H(i)(7))(4)](3) than of their analogue Al(III) in Al(OC(3)H(i)(7))(3) made the bimetallic alkoxides better catalyst in MPV reduction of ketones.

Journal Article↗
PubMed2000

Flavonoid and benzophenone glycosides from Coleogyne ramosissima.

A benzophenone glucoside and two flavonol glycosides were isolated together with 27 known polyphenols from the aerial parts of Coleogyne ramosissima, and their structures were elucidated by spectroscopic and chemical methods as iriflophenone 2-O-beta-glucopyranoside, isorhamnetin 3-O-2G-rhamnopyranosylrutinoside-7-O-alpha-rhamnopyranoside and limocitrin 3-O-rutinoside-7-O-beta-glucopyranoside, respectively.

Carbohydrate Conformation↗
PubMed1998

A benzophenone and a xanthone from Garcinia Subelliptica.

A new benzophenone derivative, 2',3',6-trihydroxy-2,4-dimethoxybenzophenone and a new xanthone, 1,6-O-dimethylsymphoxanthone have been isolated from the wood of Garcinia subelliptica. Their structures have been determined by analysis of the spectroscopic data and comparison of the NMR data with those of the compounds previously reported.

Journal Article↗
PubMed1999

Helix 6 of subdomain III A of human serum albumin is the region primarily photolabeled by ketoprofen, an arylpropionic acid NSAID containing a benzophenone moiety.

It is well known that the subdomain III A (site II) of human serum albumin (HSA) binds a variety of endogenous and exogenous substances. However, the nature of the microenvironment of the binding site remains unclear. Ketoprofen (KP), an arylpropionic acid NSAID which contains a benzophenone moiety, was used as a photoaffinity labeling agent to label the binding region. Subsequent CNBr cleavage of the photolabeled HSA revealed that the 11.6 kDa and 9.4 kDa fragments contained most of the incorporated radioactivity. Competition experiments showed that the 11.6 kDa fragment contains the common binding region for site II ligands. This fragment was redigested with Achromobacter lyticus protease I (AP-I) and the amino acid sequence of the photolabeled peptide was determined to be XCTESLVNRR, which corresponds to the sequence 476C-485K of HSA. The complete amino acid sequence of the corresponding AP-I digested HSA peptide encompasses residues 476 to 499, which form helices 5 and 6 of subdomain III A. The HSA-Myr X-ray crystallography data showed that helix 5 is involved to the least extent in ligand binding. A docking model provided further support that helix 6 represents the photolabeled region of KP.

Affinity Labels↗
PubMed2004

Hydrothermal syntheses, crystal structures, and properties of a novel class of 3,3',4,4'-benzophenone-tetracarboxylate (BPTC) polymers.

Three novel BPTC complexes, (H(2)BPTC)(4,4'-H(2)bpy)H(2)O (1), [Cd(2)Cu(HBPTC)(2)(mu(2)-4,4'-bpy)(2)(4,4'-bpy)(2)(H(2)O)(2)](n) (2), and [Co(3)(HBPTC)(2)(mu(2)-4,4'-bpy)(3)(H(2)O)(4)](n).2nH(2)O (3) (BPTC = 3,3',4,4'-benzophenone-tetracarboxylate and bpy = bipyridine), were hydrothermally synthesized. Complex 1, which is obtained as a coproduct during the syntheses of complexes 2 and 3, features a 2-D layered strong hydrogen bonding network with 2-fold interpenetration. Complex 2 has an unusual 2-D double-layered motif, which is linked together by Cu atoms in a face-to-face manner. It exhibits nanosized channels filled by 4,4'-bpy ligands. Three six-coordinated Co atoms in 3 are interlinked by HBPTC ligands to form a 2-D grid structure, which is further sustained by rigid 4,4'-bpy ligands into a 3-D open framework similar to CdSO(4) with the BPTC moieties situated in the tunnels. The thermal stabilities of complexes 1-3 were examined. The photoluminescence properties of complexes 1-2 and temperature-dependent magnetic susceptibility for 3 were also studied.

Journal Article↗
PubMed2006

Intercalation and photophysical properties of the tetra-(8-hydroxyquinolinato) boron complex and 3,3',4,4'-benzophenone tetracarboxylic anion into Mg-Al layered double hydroxides.

The tetra-(8-hydroxyquinolinato) boron complex (Bq) and 3,3',4,4'-benzophenone tetracarboxylic anion (BPTC) were successfully intercalated into layered double hydroxides with an ion-exchange method. Elemental analyses, powder X-ray diffraction, FTIR spectra, and thermogravimetric analyses indicated that the hydrothermal treatment could efficiently improve the reaction process, the purity and crystallinity of products, and that Bq and BPTC molecules steadily arranged with C2 axis perpendicular to the layer plane, and the J-type aggregate in the host interlayer, respectively. The fluorescence studies showed that, compared with those observed in the dilute solutions of the guests, the spectra of Mg3Al-Bq and Mg3Al-BPTC evolved to the high-energy side and the low-energy side with increasing their loading, respectively, which were attributed to various arrangements of guests and the increased intermolecular interaction. Furthermore, their fluorescence intensity gradually decreased with increasing the intercalated guest content due to the concentration quenching, and Mg3Al-Bq exhibits enhanced solid-state blue luminescence due to a more rigid and constrained environment of the host.

Journal Article↗
PubMed2002

Cation-recognized photosensitization in E-Z isomerization of 1,2-dichloroethylene by crowned benzophenones.

Photosensitized isomerization of 1,2-dichloroethylene with 15- and 18-membered-ring crowned benzophenones (1a and 1b) as triplet sensitizers resulted in the cation-dependent increase in the Z/E isomer ratios up to ca. 10 by addition of alkali and alkaline earth metal ions in comparison with the metal-free reactions (Z/E = 1.5-2.1). The highest Z/E values were attained for 1a with Li+ (2.9) and Mg2+ (5.3), and for 1b with Na+ (8.2) and Ca2+ (9.8), respectively, among each family of alkali and alkaline earth metal ions. It was found that the cation recognized sensitization brought about the change of the inherent triplet energy ET as well as the PhiE/Phiz ratio to raise the Z/E isomer ratio of 1,2-dichloroethylene.

Journal Article↗
PubMed2005

Light-harvesting and photoisomerization in benzophenone and norbornadiene-labeled poly(aryl ether) dendrimers via intramolecular triplet energy transfer.

A series of benzophenone (BP) and norbornadiene (NBD)-labeled poly(aryl ether) dendrimers (Gn-NBD), generations 1-4, were synthesized, and their photophysical and photochemical properties were examined. The phosphorescence of the peripheral BP (donor) chromophore was efficiently quenched by the NBD (acceptor) group attached to the focal point. Time-resolved spectroscopic measurements indicated that the lifetime of the triplet state of the BP chromophore was shortened due to the proximity of the NBD group. Selective excitation of the BP chromophore resulted in isomerization of the NBD group to quadricyclane (QC). All of these observations suggest that an intramolecular triplet energy transfer occurs in Gn-NBD molecules. The light-harvesting ability of these molecules increases with generation due to an increase in the number of peripheral chromophores. The energy transfer efficiencies are ca. 0.97, 0.54, 0.45, and 0.37 for generations 1-4, respectively, and the rate constant of the triplet-triplet energy transfer is ca. 10(6)-10(7) s(-1), which decreases inconspicuously with increasing generation. The intramolecular triplet energy transfer is proposed to proceed mainly via a through-space mechanism involving the closest donor (folding back conformation) and acceptor groups.

Journal Article↗
PubMed2005

Multiple functionalization of benzophenones inside polyphenylene dendrimers--toward entrapped ions and radicals.

Polyphenylene dendrimers possessing a defined number of keto groups in the dendritic scaffold have been synthesized by using a benzophenone-functionalized tetraphenylcyclopentadienone branching unit. A postsynthetic functionalization of the polyphenylene backbone was achieved by reacting the entrapped keto groups with organolithium reagents yielding monodisperse alcohol products. To investigate the accessibility and reactivity of the embedded groups, many functions of different size and nature, for example, the chromophore pyrene, were introduced. Moreover, suitable precursors for the synthesis of dendrimer entrapped species, trityl cations, trityl radicals, and ketyl radical anions, were obtained. To gain insight into the structure of these newly functionalized dendrimers, UV/vis, EPR, and NMR measurements have been performed. They showed a delocalization of the charge/spin into the polyphenylene dendritic arms leading to a stabilization of the ions/radicals. Remarkably, for the ketyl radicals, EPR measurements indicated the occurrence of intermolecular metal-bridged biradicals. They suggest the existence of a dendritic radical network of the dendrimers themselves.

Journal Article↗
PubMed2005

Excited state enantiodifferentiating interactions between a chiral benzophenone derivative and nucleosides.

Time-resolved measurements using nanosecond laser flash photolysis have revealed significant enantiodifferentiation in the interaction between ketoprofen (a chiral benzophenone derivative) and two relevant nucleosides, namely, thymidine and 2'-deoxyguanosine. In both cases, the highest quenching rate constants have been observed for (R)-ketoprofen, the enantiomer with lower pharmacological activity. Photoproduct studies performed in the case of thymidine suggest that the enantiodifferentiating process corresponds to a Paterno-Büchi reaction, leading to the formation of oxetanes. With 2'-deoxyguanosine, the quenching is associated with an electron-transfer process monitored through the generation of a ketyl radical.

DNA↗
PubMed2000

Ultrasound effects on the photopinacolization of benzophenone.

Ultrasonic irradiation is able to modify the course of several photochemical reactions, especially bimolecular, proceeding via triplet states. These effects were illustrated in the study of benzophenone photopinacolization in ethanol. The rates and yields increase when sonication is applied simultaneously to UV irradiation. An explanation is based on a 2-fold effect: (i) light-absorbing transient species undergo sonolytic decomposition, making the photoconversion more efficient, and (ii) sonication induces the triplet state quenching, as shown by Stern-Volmer plots from experiments run in the presence of naphthalene, probably due to the easier collisional deactivation processes favored by the homogeneous distribution of the activated species.

Journal Article↗
PubMed2003

Mechanism of an alcohol-trapping reaction in the direct and benzophenone-sensitized photodenitrogenation of a spiroepoxy-substituted azoalkane: solvent effects and stereochemical deuterium labeling.

The spin-state-dependent reactivity, singlet versus triplet, of the 2-spiroepoxy-1,3-cyclopentane-1,3-diyl DR2 has been assessed through alcohol-trapping reactions for which the effect of solvent acidity on the product distribution of the alcohol trapping products 2 versus 3 + 4 and stereochemical deuterium-labeling studies have been performed. The proposed mechanism for the solvent effect on the product ratio (2/3 + 4) reveals the importance of the hydrogen-bonded intermediates I1 and I2 in the trapping reactions; the stereochemical deuterium-labeling results clarify the dipole structure trapped by the alcohol. The dipoles DP1 and DP2, in which the configuration between the epoxide oxygen and the deuterium atoms is retained, are inferred for the direct photodenitrogenation reactions (singlet state), whereas for the benzophenone-sensitized photoreactions (triplet state), after ISC, the ring-opened dipole DP3 is implied as the intermediate that is trapped by the alcohol.

Journal Article↗
PubMed2005

Photosensitized oxygenation of sulfides within an amphiphilic dendrimer containing a benzophenone core.

Photosensitized oxygenation of sulfides within amphiphilic dendrimers, Gn [n(generation) = 1-3], consisting of a benzophenone (BZP) sensitizing core, apolar interior based on n-undecane spacer, and polar dendron exterior based on 2,2-bis(hydroxymethyl)propionic acid, has been investigated in O(2)-saturated methanol. Sulfoxide formation occurring via reaction of O(2) with triplet excited-state sulfide ((3)sulfide), which is formed by a triplet energy transfer (TET) from photoformed (3)BZP to sulfide, was accelerated by the dendric sensitizers, where G2 showed the highest yields of alkylaryl and dialkyl sulfoxides. Laser photolysis studies revealed that enhanced access of sulfide to the (3)BZP core inside the apolar microenvironment accelerates the TET to sulfide, whereas prompt migration of polar sulfoxide to the polar outer shell of the dendrimer suppresses a competitive TET to sulfoxide, thus resulting in effective (3)sulfide formation. Another notable feature of the dendric sensitizer appears in oxygenation of diaryl sulfide, which is promoted by a persulfoxide intermediate formed by photooxygenation of dialkyl sulfide; photoirradiation of a mixture of diethyl sulfide (1a) and diphenyl sulfide (4a) with G2 gave 17-fold higher diphenyl sulfoxide (4b) yield than that obtained with unmodified BZP. The apolar microenvironment within the dendric sensitizer encapsulates a large quantity of 4a, which is oxidized effectively by the persulfoxide of 1a, thus resulting in high 4b yield. The BZP core within the dendric sensitizer is stable even by photoexcitation in protic solvent, suggesting potential utilities of this dendric system for effective and selective photosensitized oxygenation of sulfides.

Journal Article↗
PubMed2005

C-O bond cleavage of benzophenone substituted by 4-CH2OR (R = C6H5 and CH3) with stepwise two-photon excitation.

The C-O bond cleavage from benzophenone substituted with 4-CH2OR (p-BPCH2OR, 1-3), such as p-phenoxymethylbenzophenone (1, R= C6H5) and p-methoxymethylbenzophenone (2, R= CH3), occurred by a stepwise two-photon excitation during two-color, two-laser flash photolysis. On the other hand, no C-O bond cleavage occurred from p-hydroxymethylbenzophenone (3, R = H). The first 355-nm laser excitation of 1-3 generates p-BPCH2OR in the lowest triplet excited state (T1) which has an absorption at 532 nm. When p-BPCH2OR(T1) is excited with the second 532-nm laser to p-BPCH2OR in the higher triplet excited state (T(n)), the C-O bond cleavage occurred within the laser flash duration of 5 ns. The quantum yields of the C-O bond cleavage during the second 532-nm laser irradiation were found to be 0.015 +/- 0.007 and 0.007 +/- 0.003 for 1 and 2, respectively. Although these values are low, the diminishing 1(T1) or 2(T1) was found to convert, in almost 100% yield, to phenoxyl (C6H5O*) and p-benzoylbenzyl (BPCH2*) radicals or methoxyl (CH3O*) and BPCH2* radicals, respectively. The T(n) excitation energy, the energy barrier along the potential surface between the T(n) states and product radicals, and delocalization of the T(n) state molecular orbital including BP and CH2OR (R = C6H5, CH3, H) moieties are important factors for the occurrence of the C-O bond cleavage. It is found that the C-O bond cleavage and production of free radicals, such as BPCH2*, C6H5O*, and CH3O*, can be performed by a stepwise two-photon excitation. The present study is an example in which the chemical reactions can be selectively initiated from the T(n) state but not from the S1 and T1 states.

Journal Article↗
PubMed2006

Solvent effect on the deactivation processes of benzophenone ketyl radicals in the excited state.

The solvent effects on ketyl radicals of benzophenone derivatives (BPD) in the excited state (BPDH*(D1)) were investigated. Absorption and fluorescence spectra of BPDH*(D1) in various solvents were measured using nanosecond-picosecond two-color two-laser flash photolysis. The fluorescence peaks from BPDH*(D1) showed a shift due to the dipole-dipole interaction with the solvent molecules. The dipole moments (mu(e)) of BPDH*(D1) were estimated to be 7-10 D, indicating that BPDH*(D1) are highly polarized. It was revealed that the fluorescence lifetime (tau(f)) depends on mu(e) in acetonitrile because the stabilization by solvent molecules affects the tau(f) value in polar solvents, predominantly. On the contrary, the conformation of BPDH*(D1) plays an important role in cyclohexane because the efficiency of the unimolecular reaction from BPDH*(D1) depends on the conformation. The substituent effect on the electron transfer from BPDH*(D1) to their parent molecules was also discussed.

Journal Article↗