- Synthesis and solid-phase application of a 9-xanthenyl handle
-
The acid-labile 5-[(9-aminoxanthen-2-yl)oxy]valeric acid was prepared in a six-step route. The usefulness of the resulting handle was investigated with solid-phase peptide synthesis of cholecystokinin-8 sulfate and the phosphorylated fragment of the ζ-sub
- Somlai, Csaba,Hegyes, Peter,Fenyoe, Robert,Toth, Gabor K.,Penke, Botond,Voelter, Wolfgang
-
-
Read Online
- The involvement of xanthone and (E)-cinnamoyl chromophores for the design and synthesis of novel sunscreening agents
-
Excessive UV exposure contributes to several pathological conditions like skin burns, er-ythema, premature skin aging, photodermatoses, immunosuppression, and skin carcinogenesis. Effective protection from UV radiation may be achieved with the use of sunscreens containing UV filters. Currently used UV filters are characterized by some limitations including systemic absorp-tion, endocrine disruption, skin allergy induction, and cytotoxicity. In the research centers all over the world new molecules are developed to improve the safety, photostability, solubility, and absorption profile of new derivatives. In our study, we designed and synthesized seventeen novel molecules by combining in the structures two chromophores: xanthone and (E)-cinnamoyl moiety. The ultraviolet spectroscopic properties of the tested compounds were confirmed in chloroform solutions. They acted as UVB or UVA/UVB absorbers. The most promising compound 9 (6-meth-oxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate) absorbed UV radiation in the range 290–369 nm. Its photoprotective activity and functional photostability were further evaluated after wet milling and incorporation in the cream base. This tested formulation with compound 9 possessed very beneficial UV protection parameters (SPFin vitro of 19.69 ± 0.46 and UVA PF of 12.64 ± 0.32) which were similar as broad-spectrum UV filter tris-biphenyl triazine. Additionally, compound 9 was characterized by high values of critical wavelength (381 nm) and UVA/UVB ratio (0.830) thus it was a good candidate for broad-spectrum UV filter and it might protect skin against UVA-induced photoaging. Compound 9 were also shown to be photostable, non-cytotoxic at con-centrations up to 50 μM when tested on five cell lines, and non-mutagenic in Ames test. It also possessed no estrogenic activity, according to the results of MCF-7 breast cancer model. Addition-ally, its favorable lipophilicity (miLogP = 5.62) does not predispose it to penetrate across the skin after topical application.
- Popió?, Justyna,Gunia-Krzy?ak, Agnieszka,S?oczyńska, Karolina,Koczurkiewicz-Adamczyk, Paulina,Piska, Kamil,Wójcik-Pszczo?a, Katarzyna,?elaszczyk, Dorota,Krupa, Anna,?mudzki, Pawe?,Marona, Henryk,P?kala, El?bieta
-
-
- Rational design of new multitarget histamine H3 receptor ligands as potential candidates for treatment of Alzheimer's disease
-
Design and development of multitarget-directed ligands (MTDLs) has become a very important approach in the search of new therapies for Alzheimer's disease (AD). In our present research, a number of xanthone derivatives were first designed using a pharmaco
- ?a?ewska, Dorota,Alachkar, Alaa,Bajda, Marek,Doroz-P?onka, Agata,Godyń, Justyna,Handzlik, Jadwiga,Kaleta, Maria,Kie?-Kononowicz, Katarzyna,Kuder, Kamil,Latacz, Gniewomir,Malawska, Barbara,Mogilski, Szczepan,Olejarz-Maciej, Agnieszka,Saad, Ali,Sadek, Bassem,Siwek, Agata,Stary, Dorota,Sudo?, Sylwia,Walczak, Maria,Wi?cek, Ma?gorzata,Zar?ba, Paula
-
-
- REAGENTS AND PROCESS FOR DIRECT C-H FUNCTIONALIZATION
-
Thianthrene derivative of the Formula (I): wherein R1 to R8 may be the same or different and are selected from hydrogen, Cl, F, a partially or fully fluorinated C1 to C6 alkyl group, and wherein n is 0 or 1, with the proviso that at least one of R1 to R8 is not hydrogen and process for C-H functionalization of aromatic compounds using this compound.
- -
-
Page/Page column 109; 110
(2020/06/01)
-
- Ceric Ammonium Sulfate (CAS) Mediated Oxidations of Benzophenones Possessing a Phenolic Substituent for the Synthesis of Xanthones and Related Products
-
Work previously published by our group described novel methodology for the synthesis of xanthones and related products from phenolic benzophenones in a reaction mediated by ceric ammonium sulfate (CAS). In this paper we further explore this novel reaction by subjecting an additional set of phenolic benzophenones to CAS to afford a range of compounds, including xanthones, 9H-xanthen-2,9(4aH)-diones, 3H-spiro[benzofuran-2,1′-cyclohexa[2,5]diene]-3,4′-diones, and biaryl compounds. A comparison of these reactions with the more commonly used oxidant ceric ammonium nitrate (CAN) was also conducted. Based on these results, greater insight into the reaction mechanism has been gained. In addition, the conversion of the synthesized xanthen-2,9(4aH)-diones to xanthones by treatment with sodium dithionite is described.
- Dam, Jean,Bode, Moira L.,De Koning, Charles B.
-
p. 150 - 160
(2019/01/10)
-
- Site-Selective C?H Oxygenation via Aryl Sulfonium Salts
-
Herein, we report a two-step process forming arene C?O bonds in excellent site-selectivity at a late-stage. The C?O bond formation is achieved by selective introduction of a thianthrenium group, which is then converted into C?O bonds using photoredox chemistry. Electron-rich, -poor and -neutral arenes as well as complex drug-like small molecules are successfully transformed into both phenols and various ethers. The sequence differs conceptually from all previous arene oxygenation reactions in that oxygen functionality can be incorporated into complex small molecules at a late stage site-selectively, which has not been shown via aryl halides.
- Sang, Ruocheng,Korkis, Stamatis E.,Su, Wanqi,Ye, Fei,Engl, Pascal S.,Berger, Florian,Ritter, Tobias
-
p. 16161 - 16166
(2019/11/03)
-
- Design, synthesis, and anticonvulsant activity of some derivatives of xanthone with aminoalkanol moieties
-
A series of new xanthone derivatives have been synthesized and evaluated for their anticonvulsant properties in the maximal electroshock, subcutaneous metrazole tests and for neurotoxicity in the rotarod in mice, i.p. and rats, p.o. Compound 9: R,S-2-{2-[(1-hydroxybutan-2-yl]amino)ethoxy}-9H-xanthen-9-one and compound 12: R,S-2-{3-[(1-hydroxybutan-2-yl)amino]propoxy}-9H-xanthen-9-one exerted activity in rats, p.o. 2 and 4?h after administration, respectively. Therefore, metabolic stability of the compounds was evaluated with use of rat microsomes, resulting in half-life t1/2 136 and 108?min, respectively, indicating that either the metabolites are very active or the parent compounds exert ADME properties other than metabolism which influence the late onset of activity.
- Waszkielewicz, Anna M.,S?oczyńska, Karolina,P?kala, El?bieta,?mudzki, Pawe?,Siwek, Agata,Grybo?, Anna,Marona, Henryk
-
p. 339 - 352
(2017/04/03)
-
- Synthesis and fluorescence of xanthone amino acids
-
Fmoc- and Boc-protected α-amino acids bearing xanthone as side chain are easily accessible by palladium-catalyzed cross-coupling of a xanthone triflate with appropriate amino acid residues. The xanthone triflate was obtained in three steps taking advantag
- Hoppmann, Christian,Alexiev, Ulrike,Irran, Elisabeth,Rück-Braun, Karola
-
p. 4585 - 4587
(2013/08/23)
-
- A comprehensive study on infrared spectra of 2-hydroxyxanthone
-
A study on the IR spectra of 2-hydroxyxanthone that was both experimental and theoretical was carried out in this work. The optimized structure and related spectral parameters were obtained by using the Becke-3-Lee-Yang-Parr (B3LYP) method with the 6-31G* and 6-311G** basis sets. The corresponding geometrical parameters were compared with each other. Detailed assignments of the vibration frequencies were performed. The agreement between the scaled theoretical frequencies and the observed frequencies was found to be quite good. Also, the calculation accuracies of the two basis sets are close. Copyright Taylor & Francis Group, LLC.
- Qu, Ruijuan,Zhang, Qi,Zhang, Xuesheng,Wang, Zunyao
-
p. 240 - 245
(2012/08/27)
-
- Rhodium-catalyzed xanthone formation from 2-aryloxybenzaldehydes via cross-dehydrogenative coupling (CDC)
-
A concise and straightforward strategy to construct a xanthone skeleton via an intramolecular cross-dehydrogenative coupling (CDC) of 2- aryloxybenzaldehydes has been developed. The reaction proceeded smoothly without any need of preactivation of the aldehyde group. It can tolerate various functional groups and provides an applicable protocol to construct a wide range of xanthone derivatives.
- Wang, Ping,Rao, Honghua,Hua, Ruimao,Li, Chao-Jun
-
supporting information; scheme or table
p. 902 - 905
(2012/04/05)
-
- Design and synthesis of aryloxyethyl thiocyanate derivatives as potent inhibitors of Trypanosoma cruzi proliferation
-
As a part of our project directed at the search of new chemotherapeutic agents against American trypanosomiasis (Chagas' disease), several drugs possessing the 4-phenoxyphenoxy skeleton and other closely related structures employing the thiocyanate moiety as polar end group were designed, synthesized, and evaluated as antiproliferative agents against Trypanosoma cruzi, the parasite responsible for this disease. These thiocyanate analogues were envisioned bearing in mind the potent activity shown by 4- phenoxyphenoxyethyl thiocyanate (compound 8) taken as lead drug. This compound had previously proved to be an extremely active growth inhibitor against T. cruzi with IC50 values ranging from the very low micromolar level in epimastigotes to the low nanomolar level in the intracellular form of the parasite. Of the designed compounds, the ethyl thiocyanate drugs connected to nonpolar skeletons, namely, arylthio, 2,4-dichlorophenoxy, ortho-substituted aryloxy, and 2-methyl-4-phenoxyphenoxy (compounds 15, 34, 47, 52, 72, respectively), were shown to be very potent antireplicative agents against T. cruzi. On the other hand, conformationally restricted analogues as well as branched derivatives at the aliphatic side chain were shown to be moderately active against T. cruzi growth. The biological activity of drugs bearing the thiocyanate group correlated quite well with the activity exhibited by their normal precursors, the tetrahydropyranyl ether derivatives, when bonded to the same nonpolar skeleton. Compounds having the tetrahydropyranyl moiety as polar end were proportionally much less active than sulfur-containing derivatives in all cases. Drugs 47 and 72 also resulted to be very active against the amastigote form of the parasite growing in myoblasts; however, they were slightly less active than the lead drug 8. On the other hand, compounds 34 and 52 were almost devoid of activity against myoblasts. Surprisingly, the dithio derivative 15 was toxic for myoblasts.
- Szajnman, Sergio H.,Yan, Wen,Bailey, Brian N.,Docampo, Roberto,Elhalem, Eleonora,Rodriguez, Juan B.
-
p. 1826 - 1840
(2007/10/03)
-
- Xanthan-ester and acridan substrates for horseradish peroxidase
-
Xanthan esters and acridans are substrates for horseradish peroxidase. These stable, enzymatically cleavable chemiluminescent esters are substrates for horseradish peroxidase which, together with peroxide is among the extensively used enzyme in enzyme-linked detection methods, including immunoassays, oligonucleotide detection and nucleic acid hybridization. The novel compounds are used, together with peroxide, alkali and the peroxidase, to indicate the presence and/or concentration of target compounds. The assays may be enhanced by the use of polymeric quaternary onium enhancement compounds or similar compounds selected to enhance the chemiluminescence emitted.
- -
-
-
- QUINUCLIDINE DERIVATIVE HAVING TRICYCLIC HETERO CONDENSED RING
-
A quinuclidine derivative represented by the following general formula (I), a pharmaceutically acceptable salt thereof, a hydrate thereof or a solvate thereof, which has strong squalene synthase inhibiting activity and is useful as a cholesterol lowering agent without causing side effects. (I) (Symbols in the formula represent the following meanings; R1:a hydrogen atom, a halogen atom or a lower alkyl group, R2:a hydrogen atom, a hydroxyl group or a lower alkoxy group, +E,ovs . . .+EE :a single bond or a double bond, with the proviso that R2 does not exist when +E,ovs . . .+EE is a double bond, X and Y:the same or different from each other and each represents a bond, an oxygen atom (-O-), a carbonyl group (-CO-), a group represented by the formula -S(O)p- or a group represented by the formula -NR3-, p:0, 1 or 2, R3:a hydrogen atom or a lower alkyl group which may have a substituent, A:a saturated or unsaturated lower alkylene group, a group of the formula -(CH2)mZ(CH2)n- or a group of the formula -(CH2)mZ(CH2)nCR4=, Z:an oxygen atom (-O-), a group of the formula -S(O)q-, a carbonyl group (-CO-) or a group of the formula -NR5-, R4:a hydrogen atom, a halogen atom or a lower alkyl group, R5:a hydrogen atom or a lower alkyl group, m and n:the same or different from each other and each is 0 or an integer of 1 to 5, m+n:an integer of 1 to 5 q:0, 1 or 2, with the proviso that, when either one of X and Y is a bond, A is a group represented by the formula -(CH2)mZ(CH2)nCR4=
- -
-
-
- Preparation and applications of xanthenylamide (XAL) handles for solid-phase synthesis of C-terminal peptide amides under particularly mild conditions
-
[[9-[(9-Fluorenylmethyloxycarbonyl)amino]xanthen-2(or 3)-yl]oxy]alkanoic acid (XAL) handles have been prepared by efficient four-step routes from 2- or 3-hydroxyxanthone and coupled onto a range of amino-functionalized supports. The resultant XAL supports are the starting points for solid-phase peptide synthesis by Fmoc chemistry. Upon completion of chain assembly, C-terminal peptide amides are released in excellent yields and purities by use of low concentrations [1-5% (v/v)] of trifluoroacetic acid (TFA) in dichloromethane, often without a need for added carbocation scavengers. These cleavage conditions allow retention of all or a significant portion of tert-butyl type and related side-chain protecting groups, which subsequently may be removed fully in a solution process carried out at higher acid concentration. XAL supports are particularly useful for the synthesis of acid-sensitive peptides, including tryptophan-containing sequences that are known to be susceptible to yield- and/or purity-reducing alkylation side reactions. The effectiveness of this chemistry was shown with the syntheses of prothrombin (1-9), acyl carrier protein (65-74), Tabanus atratus adipokinetic hormone, fragments of the protein RHK 1, CCK-8 sulfate, and oxytocin. Furthermore, the application of XAL supports for the preparation of fully protected peptide amides has been demonstrated.
- Han,Bontems,Hegyes,Munson,Minor,Kates,Albericio,Barany
-
p. 6326 - 6339
(2007/10/03)
-
- BeCl2 as a new highly selective reagent for dealkylation of aryl-methyl ethers
-
An efficient and simple method is introduced for the selective removal of methyl group from poly aryl-methyl ethers, in some important derivatives of benzophenones, xanthones, anthraquinones, aryl esters, benzamides and nitroanisoles with BeCl2.
- Sharghi, Hashem,Tamaddon, Fatemeh
-
p. 13623 - 13640
(2007/10/03)
-
- Xanthenylamide handle for use in peptide synthesis
-
The preparation and properties of xanthenylamide handles for use in peptide synthesis is disclosed. The compounds, omega-(9-(9-fluorenylmethyloxycarbonyl)aminoxanthan-2-oxy)alkanoic acid derivatives, are used as peptide handles in the solid-phase synthesis of peptide amides.
- -
-
-
- Xanthenylamide handle for use in peptide synthesis
-
The preparation and properties of xanthenylamide handles for use in peptide synthesis is disclosed. The compounds, Fmoc-9H-2-alkyleneoxycarboxy-xanthene-9-amines, are used as peptide handles in the solid phase synthesis of peptide amides.
- -
-
-
- An Abnormal Thermal Condensation of Hydroquinone with Ethyl Salicylate
-
Thermal condensation of hydroquinone with ethyl salicylate in refluxing diphenyl ether affords 1-hydroxyxanthone (I), 1,4-disalicyloxyhydroquinone (IIa), 4'-hyroxyphenyl salicylate (III), 1-hydroxy-4-salicyloxyxanthone (IVa), 1,4-dihydroxyxanthone (V) and 2-hydroxyxanthone (VI).The structures of these comnpounds have been confirmed by PMR and mass spectral data.
- Patel, Ghanshyam, N.,Trivedi, Kunjbihari, N.
-
p. 458 - 459
(2007/10/02)
-
- 3-ARYL- AND 3-(ARYLOXY)PHTHALIC ACIDS IN THE SYNTHESIS OF FLUORENONES AND XANTHONES
-
Aryl- and aryloxyfurans can serve as the starting compounds in the synthesis of fluorenones, xanthones, and diazafluoranthenes.
- Oleinik, A. F.,Adamskaya, E. V.
-
p. 1221 - 1224
(2007/10/02)
-