Synthesis and Evaluation of Chalcone Derivatives as Novel Sunscreen Agent

Ultraviolet (UV) irradiation is a serious problem for skin health thus the interest in the research to develop sunscreen agent has been increasing. Chalcone is a promising compound to be developed as its chromophore absorbs in the UV region. Therefore, in the present work, we synthesized eight chalcone derivatives through Claisen–Schmidt condensation at room temperature. The evaluation of the optical properties of each chalcone derivatives in the UV region was conducted through spectroscopic and computational studies. The synthesized chalcones were obtained in good yields and they were active in the UV region. The results revealed that more methoxy substituents to chalcone leads toward red shift. All chalcone derivatives have high molar absorptivity value (21,000–56,000) demonstrating that they have the potential to be used as the sunscreen agent. The cytotoxicity assay showed that chalcone derivatives were demonstrating low toxicity toward normal human fibroblast cell, which is remarkable. Therefore, we concluded that the synthesized chalcones in this work were potential to be developed as novel sunscreen agents in real application.     

侧基上带有C60基团的聚苯乙烯的表征

用UV、FTIk、DSC、TG和DTA及GPC等方法证明了通过三步反应(氯甲基化,叠氮化,环加成反应)确实将C₆₀引入到聚苯乙烯的侧基上,C₆₀基本上以单取代的方式存在,并通过TG和DTA方法估算了C₆₀在聚苯乙烯C₆₀衍生物中的含量。     

An Unprecedented Photochemical Reaction for Anthracene‐Containing Derivatives

A series of anthracene‐containing derivatives have been synthesised and characterised. The photochemical behaviour of these derivatives have been investigated by ¹H NMR spectroscopy. An unprecedented photolysis reaction for anthracene‐containing derivatives was observed in the case of anthracenes directly armed with a ‐CH₂O‐R group upon UV irradiation. The photolysis reaction process has been demonstrated to occur in three steps. Firstly, the anthracene‐containing derivatives are converted into the corresponding endoperoxide intermediate upon UV irradiation in the presence of air; then, the endoperoxide intermediate is decomposed to the corresponding starting compound and 9‐anthraldehyde; finally, 9‐anthraldehyde is further oxidised to anthraquinone. Additionally, the photolysis reaction of anthracene‐containing derivatives is significantly promoted in the presence of a thiacalix[4]arene platform.     

Photobase generation from amineimide derivatives and their use for curing an epoxide/thiol system

The structural effects of amineimide derivatives on photobase generation and the use of the resultant base for thermal curing of an epoxide/thiol system are investigated. The results of UV spectral change and gas chromatographic‐mass spectrometric analysis indicated that amineimide derivatives undergo photolysis by UV irradiation and generate bases. The order of conversion of the photolysis for the functional groups introduced to amineimide derivatives was NO₂ > N(CH₃)₂ > CN > OCH₃ > H. By using aminimide derivatives with NO₂ and N(CH₃)₂ groups, the curing of the epoxide/thiol system was shifted to lower temperature after UV irradiation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4045–4052, 2002     

Solid‐Phase Synthesis of Polyamine Spider Toxins and Correlation with the Natural Products by HPLC‐MS/MS

A recently developed new and divergent approach for the solid‐phase synthesis of polyamines and polyamine derivatives was extended to the preparation of linear pentamines, and it was applied to the synthesis of three quartets of isomeric polyamine spider toxins. The twelve synthetic acylpolyamines were investigated by HPLC‐UV(DAD)‐MS and HPLC‐UV(DAD)‐MS/MS and compared with the natural products in the complex mixture of the venom of Agelenopsis aperta. The comparative investigation supported the structures and assignments of seven previously found toxins and allowed the identification of an additional five polyamine derivatives in the natural sample. The MS/MS study of the isomerically pure polyamine derivatives revealed furthermore a characteristic pattern for the fragmentation of these compounds, which can possibly be used as evidence in the trace analysis of other polyamine derivatives.     

Star-Shaped Ferrocene-Based 1,4-Disubstituted-1,2,3-Triazole Derivatives: Synthesis,Characterization, and Investigation of Linear Optical and Electrochemical Properties

In this study, the star-shaped ferrocene-based 1,4-disubstituted-1,2,3-triazole derivatives were designed and synthesized via Huisgen reaction. For this purpose, the [3 + 2] cycloaddition reaction between multi-(4-azidobutyl) substituted ferrocene derivatives and ethynylferrocene was carried out in the presence of CuSO₄.5H₂O as Cu (I) source and ascorbic acid as reluctant for convert the Cu (II) to Cu (I). The optical and electrochemical properties of the final dendrimer-like ferrocenyl derivatives were evaluated using UV–vis spectroscopy (UV–vis) and cyclic voltammetry (CV) techniques, respectively. The linear relationship between the cathodic and anodic peak currents and the square root of the scan rate was indicated the diffusion-limited mechanism for the redox process. Furthermore, ferrocene-based 1,4-disubstituted-1,2,3-triazole derivatives show good electrochemical behavior (the CV and DPV technique) when immobilized on glassy carbon electrode surface using Nafion. In addition, the quantum chemistry study was performed on the synthesized compounds with the DFT approach. The B3LYP/6-31G(d) method was applied to do TD-DFT calculations due to its good agreement with experimental data for prediction of UV–Vis spectra.     

Unlocking the pH‐Responsive Degradability of Fumaramic Acid Derivatives Using Photoisomerization

Fumaramic acid derivatives can be converted into their cis isomer maleamic acid derivatives under UV illumination, and these maleamic acid derivatives show pH‐responsive degradability at acidic pH only after the preceding photoisomerization. The rate of the tandem photoisomerization–degradation of fumaramic acid derivatives can be finely controlled by changing the substituents on the double bond. Photoisomerization‐based unlocking of the pH‐responsive degradability of fumaramic acid derivatives has strong potential for the development of multisignal‐responsive smart materials in biomedical applications.     

N1-(2-furoylmethyl) and N1-(5-nitro-2- furoylmethyl) derivatives of uracil and its 5-substituted derivatives

The corresponding N₁-(2-furoylmethyl) and N₁-(5-nitro-2-furoylmethyl) derivatives of uracil and its 5-substituted derivatives were obtained by the reaction of 2-bromo- and 5-nitro-2-bromoacetylfurans with uracil, 5-fluorouracil, and thymine. The structures of these compounds as N₁-substituted uracils were proved by a study of the UV spectra at various pH values. The computational method of expanding the UV spectra into individual bands was used.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1268–1270, September, 1971.     

A FLUORESCENCE STUDY OF THE INTERACTION OF INDOLIC COMPOUNDS WITH SYNTHETIC POLYELECTROLYTES

Abstract— –The interaction of indole derivatives with synthetic polyelectrolytes was investigated using UV absorption and fluorescence spectroscopy. The presence of both sodium poly(styrene sulfonate) (PSS) and sodium polyvinyl sulfonate) (PVS) inhibits the fluorescence quenching of 1-pyrene sulfonic acid by tryptamine. The effect is more marked for PSS than for PVS. There was no polyelectrolyte effect on the quenching by tryptophan. It was also found that aromatic polyelectrolytes strongly quench the fluorescence of indole derivatives of opposite charge by a static mechanism. This is accompanied by a new absorption in the red extreme of the UV spectrum of the mixtures. The systems investigated were tryptamine-PSS and polyvinyl benzyl trimethylammonium chloride) with the anions of indole-3-alkanoic acids. Equilibrium constants for the binding of the indole derivatives to the polyelectrolytes were determined. The fluorescence of zwitterionic tryptophan is not affected by the presence of the polyelectrolytes.     

Studies in sesquiterpenes—XX Acetoxymethylation of longifolene

Longifolene in Prins reaction with formaldehyde yielded the expected ω-acetoxymethyl longifolene, which was transformed into a number of interesting derivatives. Configuration of the Prins product has been arrived at by NMR measurements. The UV absorption of these derivatives show a considerable bathochromic shift with respect to those in the camphene series and this could be attributed to the slight twisting of the ethylenic linkage in longifolene and its derivatives.     

Protective Properties of Novel S‐Acyl‐Glutathione Thioesters Against Ultraviolet‐induced Oxidative Stress

UV‐induced toxicity is characterized by marked oxidative stress, accompanied by the depletion of key cellular antioxidants, particularly glutathione (GSH). Replenishing cellular GSH may represent a means of counteracting UV‐induced toxicity: however, treatment with free GSH is not therapeutically effective due to its unfavorable pharmacokinetic properties. In this study, we show that S‐acyl‐glutathione (acyl‐SG) derivatives, which consist of an acyl chain (of variable length and saturation) linked via a thioester bond to GSH, increase intracellular levels of reduced GSH in primary skin fibroblasts, adenocarcinoma HeLa and neuroblastoma SH‐SY5Y cells. Consistent with this, acyl‐SG derivatives protect against UV‐induced reactive oxygen species (ROS) production and UV‐B/C‐mediated lipid peroxidation and caspase‐3 activation in the analyzed cell lines, with unsaturated thioesters displaying a significantly greater protective effect. Taken together, our findings suggest that acyl‐SG thioesters may be therapeutically effective in the treatment of UV‐related skin disorders and oxidative stress‐mediated conditions in general.     

Novel UV-sensitive bis-chalcone derivatives: synthesis and photocrosslinking properties in solution and solid PMMA film

A series of chalcone derivatives in which two chalcone groups are attached by alkyldioxy chains were synthesized and characterized by ¹H NMR, UV–Vis, and Fourier transform infrared (FTIR) spectral analysis. Upon the irradiation of 365-nm UV light, the chalcone groups in the molecules underwent [2π + 2π] photodimerization. The photocrosslinking properties were investigated both in solution and in polymethyl methacrylate (PMMA) solid films on quartz plate. It has been found that the photocrosslinking rates of the compounds depended on the different flexibility of the functional groups, which was determined by the length of the spacer chain between the two chalcone moieties. The longest soft chain containing derivatives has a faster photocrosslinking rate both in solution and in solid film. Irradiated by polarized ultraviolet light (PUV), all of the films doped with bis-chalcone derivatives showed an anisotropic absorption property, which may give a promising application as LC-alignment materials.     

Characterization and application of a new ultraviolet derivatization reagent for amino acids analysis in capillary electrophoresis

A new ultraviolet (UV) labeling reagent, p-acetamidobenzenesulfonyl fluoride (PAABS-F), was designed and synthesized to label and determine the amino acids by capillary electrophoresis (CE) with diode-array detector (DAD). PAABS-F is very stable and easy to synthesize. It reacted with primary or secondary amino acids very quickly under facile conditions to give corresponding derivatives in high yield with excellent sensitivity and stability. No by-products were observed in amino acid derivatives when stored at room temperature under natural daylight for at least 7 days. Both amino acids standard solution and real samples reacted with this new UV labeling reagent smoothly to form high UV-absorption derivatives. The labeled 20 standard amino acids were efficiently separated by CE and the mass detection limits (S/N = 3) were ranged from 59.3 fmol for l-tryptophan to 1.70 pmol for l-histidine.     

共轭CN与非共轭CF3吸电子取代基对PPV类衍生物分子结构及光电性质的影响

运用密度泛函DFT B3LYP／6-31G(d)方法对CN和CF3吸电子基团取代的PPV类衍生物的三聚体进行了几何构型优化,并采用含时密度泛函TD-DFT、B3LYP／6-31G(d)方法计算了其相应化合物的紫外吸收光谱．通过对CN和CF3取代的PPV类衍生物的分子几何结构、前线分子轨道能级、电子云分布规律的分析,从理论上解释了共轭CN与非共轭CF3吸电子取代基对其光谱性质影响的差异：前者使相应PPV类衍生物的吸收光谱发生红移,后者则发生蓝移．计算结果还表明用TD-DFT方法计算该体系的紫外吸收光谱值与实验数据吻合得很好;另外引入CN和CF3基团之后,使其相应的PPV衍生物的LUMO能级降低,电子亲合势增加,都是很好的电子传输材料．     

Functional monomers and polymers. XCIV. Photochemical reactions on the synthetic polymers containing thymine bases in the presence of adenine derivatives

Photodimerization reactions of polyacrylate and polymethacrylate derivatives and the dimer model compound containing thymine bases were studied in the presence of adenine derivatives in dimethyl sulfoxide; N,N-dimethylformamide; and dimethyl sulfoxide–ethylene glycol solutions. The photodimerization of thymine bases both in the polymers and in the dimer model compound was found to be quenched by the addition of adenine derivatives. Base-base interaction in the ground state was also studied by ultraviolet (UV) spectroscopy in the three solvents. The quenching of the photodimerizationof thymine bases in the presence of adenine derivatives was discussed in terms of the specific interaction between adenine and thymine bases both in ground and excited states.     

Photophysics and photochemistry of the 2,4,6-triphenyl-2-benzyl-2H-thiopyran versus 2H-pyran derivatives

The photochemistry and photophysics of one thiopyran (2,4,6-triphenyl-2-benzyl-2H-thiopyran) and two pyran (2,4,6-triphenyl-2H-pyran and 2,4-dimethyl-2,6-diphenyl-2H-pyran) derivatives were investigated by stationary and time resolved techniques. Both theory and experiments indicated a π,π^* character for the lowest singlet states of these molecules, located in the UV region approximately at the same energy. Upon stationary UV irradiation at low temperature, colourless photoproducts were formed from the pyran derivatives, while coloured compound(s) were obtained from the thiopyran. Long-lived transients were observed at room temperature, which were assigned to the photoproducts obtained at low temperature; only in one case (2,4,6-triphenyl-2H-pyran) a triplet precursor was detected.     

Photochromic properties of diarylethene derivatives having chryso[b]thiophene rings

Diarylethene derivatives having one or two chryso[b]thiophene ring(s) have been synthesized. In solution the derivatives underwent photochromism and the derivative with one chryso[b]thiophene ring exhibited photochromism even in the single crystalline phase. The color of the UV irradiated single crystal changed from blue to green by rotation the sample under polarized light.     

Application of SBA-Pr-SO<Subscript>3</Subscript>H in the synthesis of 2,3-dihydroquinazoline-4(1<Emphasis Type="Italic">H</Emphasis>)-ones: characterization,UV–Vis investigations and DFT studies

An efficient one-pot synthesis of 2,3-dihydroquinazoline-4(1H)-one derivatives 4a–l is described using SBA-Pr-SO₃H as a heterogeneous acid catalyst. The present methodology resulted in various derivatives of 2,3-dihydroquinazoline-4(1H)-one in good yield via a three-component reaction of isatoic anhydride, aldehydes and ammonium acetate. SBA-Pr-SO₃H played a significant role as an efficient mesoporous catalyst due to its pore size of 6 nm. Additionally, UV–Vis spectrum of the products was studied in order to investigate their application as UV absorbers.     

Chemical Investigations of the Molecular Origin of Biological Radiation Damage

The radiation damage observed when UV and ionizing radiations react on biological objects is caused in many cases by changes in the nucleic acids. Exposure of these compounds to UV radiation in vitro and in vivo leads, inter alia, to dimerization of the pyrimidine bases with formation of cyclobutane derivatives, and to addition of water to the 5,6-double bond of the pyrimidine bases to form derivatives of the 6-hydroxyhydropyrimidine system. The structure of the irradiation products has been established. The dimerization prevents the reduplication of the DNA, and the addition of water appears to be the cause of UV mutations. Ionizing radiation in aqueous solution results e.g. in addition of H and/or HO radicals to the 5,6-double bond of the pyrimidine bases and cleavage of the imidazole ring of the purine bases. The mutations caused by ionizing radiation are probably also due, in part, to the formation of 6-hydroxydihydropyrimidine derivatives.     

Naturally occurring sesquiterpene-coumarin ethers,VI. New sesquiterpene-isofraxidin ethers fromAchillea depressa

The roots ofAchillea depressa afforded in addition to known sesquiterpene-isofraxidine ethers three new derivatives: the bicyclic drimenol derived albartol and the monocyclic derivatives deparnol and acetyldeparnol. The compounds were characterized by¹H-NMR, MS, UV, IR, and CD data.Herrn Prof. Dr.U. Schmidt mit den besten Wünschen zum 60. Geburtstag gewidmet.