- New carboxymethyl cellulose tosylate with low biodeterioration
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Microbial biodegradation and biodeterioration of cellulose based thickeners is a serious problem in industry. A new tosylic ester of carboxymethyl cellulose (TsCMC) was prepared with anhydride of p-toluensulphonic acid. The TsCMC has improved rheological properties, higher viscosity and pseudoplasticity, superior emulsification properties and decreased wettability compared to parental CMC. The biodeterioration of TsCMC was significantly reduced compared to parental CMC or other commercially used modified cellulose thickeners in water based paint industry. Improved rheological properties combined with low biodeterioration make TsCMC a promising new material for industrial applications with a potential to reduce the use of hazardous antimicrobial agents.
- Orehek, Janez,Petek, Klemen,Dogsa, Iztok,Stopar, David
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- An improved synthesis of 6-O-monotosyl-6-deoxy-β-cyclodextrin
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Addition of p-toluenesulfonic anhydride (Ts2O) to β-cyclodextrin (CD) in water, followed by treatment with 10% aqueous NaOH solution for 10 min and removal of excess Ts2O by filtration, gave mono-6-deoxy-6-(O-p- toluenesulfonyl)-CD (1) in 61% yield.
- Zhong, Ning,Byun, Hoe-Sup,Bittman, Robert
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Read Online
- First class of phosphorus dendritic compounds containing β-cyclodextrin units in the periphery prepared by CuAAC
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A new class of phosphorus dendritic compounds (PDCs) having a cyclotriphosphazene (P3N3) core and decorated with six β-cyclodextrin (βCD) units, named P3N3-[O-C6H4-O-(CH2)n-βCD]6, where n = 3 or 4 was designed, and the synthesis was performed using copper (I) catalyzed alkyne-azide cycloaddition (CuAAC). To obtain the complete substitution of the P3N3, two linkers consisting of an aromatic ring and an aliphatic chain of two different lengths were assessed. We found that, with both linkers, the total modification of the periphery was achieved. The two new obtained dendritic compounds presented a considerably high water solubility (>1 g/mL). The compounds comprised in this new class of PDCs are potential drug carrier candidates, since the conjugation of the βCD units to the P3N3 core through the primary face will not only serve as surface cover but, also, provide them the faculty to encapsulate various drugs inside the βCDs cavities.
- Caminade, Anne-Marie,González-Méndez, Israel,Illescas, Javier,Moineau-Chane Ching, Kathleen I.,Rivera, Ernesto,Sorroza-Martínez, Kendra,Vonlanthen, Mireille
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- Efficient modification of PAMAM G1 dendrimer surface with β-cyclodextrin units by CuAAC: Impact on the water solubility and cytotoxicity
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The toxicity of the poly(amidoamine) dendrimers (PAMAM) caused by the peripheral amino groups has been a limitation for their use as drug carriers in clinical applications. In this work, we completely modified the periphery of PAMAM dendrimer generation 1 (PAMAM G1) with β-cyclodextrin (β-CD) units through the Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) to obtain the PAMAM G1-β-CD dendrimer with high yield. The PAMAM G1-β-CD was characterized by 1H- and 13C-NMR and mass spectrometry studies. Moreover, the PAMAM G1-β-CD dendrimer showed remarkably higher water solubility than native β-CD. Finally, we studied the toxicity of PAMAM G1-β-CD dendrimer in four different cell lines, human breast cancer cells (MCF-7 and MDA-MB-231), human cervical adenocarcinoma cancer cells (HeLa) and pig kidney epithelial cells (LLC-PK1). The PAMAM G1-β-CD dendrimer did not present any cytotoxicity in cell lines tested which shows the potentiality of this new class of dendrimers.
- González-Méndez, Israel,Illescas, Javier,Martínez-Serrano, Ricardo D,Rivera, Ernesto,Ruiu, Andrea,Solano, José D,Sorroza-Martínez, Kendra,Zhu, Xiao Xia
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p. 25557 - 25566
(2020/10/02)
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- Sulfonylation of aromatic compounds with methyl p-toluenesulfonate as a sulfonylating precursor
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We have developed Friedel-Crafts (FC) sulfonylation of aromatic compounds with methyl p-toluenesulfonate as a sulfonylating precursor. In this procedure, methyl p-toluenesulfonate was treated and activated with pyridine to produce N-methylpyridinium p-toluenesulfonate as a sulfonylation reagent. Reactivity of this salt for the sulfonylation of mesitylene was investigated in the presence of three different promoters, such as triflic anhydride, dimethylsulfide ditriflate, and triphenylphosphine ditriflate (TPPD). All of the promoters show chemoselectivity and among them, TPPD presents a chemoselectivity in FC sulfonylation. Iranian Chemical Society 2012.
- Khodaei,Nazari
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p. 507 - 512
(2013/02/22)
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- Gas-phase catalytic Beckmann rearrangement over crystalline BPO4 of dehydration ability
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The crystalline BPO4 with a P/B ratio around 1.5 prepared by dehydration of boric and phosphoric acid was found to be an effective heterogeneous catalyst for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. Copyright
- Tsuji, Hideto,Setoyama, Tohru
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p. 1232 - 1233
(2007/10/03)
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- SYNTHESIS OF STERICALLY HINDERED SECONDARY AMINOETHER ALCOHOLS
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Severely sterically hindered secondary aminoether alcohols are prepared by reacting organic carboxylic, organic carboxylic acid halides, acid anhydrides or a ketene with an alkyl, alkaryl or alkylhalo sulfonate to yield a sulfonic. Carboxylic anhydride compound which is then reacted with a dioxane to cleave the ring of the dioxane, yielding a cleavage product which cleavage product is then aminated with an alkylamine and hydrolyzed with base to yield the severely sterically hindered secondary aminoether alcohol.
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Page/Page column 17
(2008/06/13)
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- Stable phosphinous acids
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The electronic properties of organyl element compounds are strongly influenced by the electronic characteristics of the organic substituents. The bonding of two CF3 groups to a phosphorus atom effects a drastically decreased basicity. That is the phosphorus atom is the least basic centre in the compound (CF3)2POH. This compound, synthesized in 1960 by Burg and Griffiths, is the only known example of a phosphinous acid, although there should be a general interest in this class of compounds. However, only a few investigations have been reported which may be explained by the tedious and risky synthesis. In this paper a safe one step and high yield synthesis of (CF3)2POH is described. The compound (C6F 5)2POH, originally claimed as a phosphinous acid, is proved to exist at room temperature exclusively in the tautomeric oxide form. (C6F5)2P(O)H crystallizes in the triclinic space group P1? (no. 2) with a 992.9(1) pm; b 1501.9(2) pm; c 1539.4(2) pm; α 117.48(1)°; β 100.39(1)°; γ 96.02(1)° and Z 6. Quantum chemical investigations prove the electron withdrawing effect of s-triazinyl groups (1,3,5-triazin-4-yl derivatives) to be much stronger than that of pentafluorophenyl groups. Quantum chemical calculations at the B3PW91/6-311G(3d,p) level of theory predict for the bis(s-triazinyl) derivative (C3N3H2)2POH the phosphinous acid isomer to be favored by ΔEZP = 22 kJ/mol in relation to the corresponding phosphane oxide isomer. The phosphinous acid (CF3) 2POH (Cs symmetry) is favored at the same level of theory by about ΔEZP = 14 kJ/mol compared with the phosphane oxide structure (Cs symmetry).
- Hoge, Berthold,Neufeind, Stefan,Hettel, Sonja,Wiebe, Waldemar,Th?sen, Christoph
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p. 2382 - 2387
(2007/10/03)
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- Process for functionalising a phenolic compound carrying an electron-donating group
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The invention concerns a method for functionalizing a phenolic compound bearing an electron-donor group, in said group para position, inter alia a method for the amidoalkylation of a phenolic compound bearing an electron-donor group, and more particularly, a phenolic compound bearing an electron-donor group preferably, in the hydroxyl group ortho position. The method for functionalizing in para position with respect to an electron-donor group carried by a phenolic compound is characterised in that the phenolic compound bearing an electron-donor group is subjected to the following steps: a first step which consists of protecting the hydroxyl group in the form of a sulphonic ester function; a second step which consists in reacting the protected phenolic compound with an electrophilic reagent; optionally, a third step deprotecting the hydroxyl group.
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- Syntheses of 6-deaminosinefungin and (S)-6-methyl-6-deaminosinefungin
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The nucleosides S-adenosylmethionine (SAM, AdoMet) and S-adenosylhomocysteine (SAH, AdoHcy) are involved in a number of important enzyme systems. The direct or indirect inhibition of these enzymes is currently of high interest, particularly in the areas of antiviral and cell proliferation research. We report here the first chirospecific syntheses of 6(S)-methyl-6-deaminosinefungin (4) and 6-deaminosinefungin (5) which are analogues of SAM (1), SAH (2), and sinefungin (3). From ketone 6 (tert-butyl [methyl 2,3-O-isopropylidene-5,7,8,9-tetradeoxy-9(S)-[(p-toluenesulfonyl)amino -β-D-ribo-deculofuranosid]uronate), an intermediate in the sinefungin synthesis, the methylene derivative was prepared by using the tosylhydrazone-hydroboration method. Nucleoside formation with adenine and deprotection then led to 6-deaminosine fungin. For the synthesis of (S)-6-methyl-6-deaminosinefungin (4), ketone 6 was converted in four steps into the 6(S)-methyl derivative using a cuprate reagent. After the adenine was attached, an appropriate deprotection sequence yielded 4. Thus, 4 was synthesized in 11 stops from ketone 6 in an overall yield of 13%.
- Peterli-Roth,Maguire,Leon,Rapoport
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p. 4186 - 4193
(2007/10/02)
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- The Interaction of Arenesulphonyl Chlorides, Aluminium Chloride, and Saturated Alicyclic Hydrocarbons containing at least One Tertiary Hydrogen Atom
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Cycloalkanes having at least one tertiary hydrogen react with a mixture of benzenesulphonyl chloride and aluminium chloride in carbon disulphide, with reactivity decreasing in the order cis-decalin ca. cis-hexahydroindane > trans-decalin >/= dicyclohexyl > methylcyclohexane > t-butylcyclohexane > methylcyclopentane.Although hydrogen chloride was evolved and benzenesulphonyl chloride was reduced to benzenesulphinic acid in all the reactions, only cis-decalin, and, to a much smaller extent, dicyclohexyl, gave appreciable amounts of chloro- or dichloro-cycloalkanes.In other reactions the major products were hydrocarbon "dimers" and "trimers" apparently formed by attack by the carbenium ion on cycloalkenes formed in the reaction.Electron-attracting substituents in the arenesulphonyl chloride enhanced the rate of reaction with cis-decalin, and electron-donor substituents retarded the reaction, which appears to proceed via hydride-ion abstraction by the arenesulphonyl halide-aluminium halide "oxonium complex" rather than by the (+) ion.
- Ewedemi, Rotimi O.,Fields, Roy,Holt, Geoffrey
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p. 1466 - 1500
(2007/10/02)
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- Sulphonic Acid-induced Fragmentation of Dialkyl Acylphosphonates, Formation of Alkyl Carboxylates and Alkyl Sulphonates
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Heating of dialkyl acylphosphonates with sulphonic acids under anhydrous conditions leads to the formation of alkyl sulphonates and alkyl carboxylates. 31P N.m.r. spectroscopy revealed that the reaction of equimolar amounts of dimethyl benzoylphosphonate (1) and toluene-p-sulphonic acid at room temperature gives dimethyl phosphonate (6) in 50percent yield.It is proposed that the by-product of this reaction, benzoic toluene-p-sulphonic anhydride (8), reacts with the excess of toluene-p-sulphonic acid, to yield toluene-p-sulphonic anhydride (9) and benzoic acid.Heating of these two compounds with dimethyl phosphonate was shown to yield methyl toluene-p-sulphonate and methyl benzoate, respectively.A postulated by-product of these reactions is phosphenous acid (HPO2).Quantum mechanical calculations by the MNDO/H method carried out on dimethyl benzoylphosphonate and its protonation products show that the preferred site of protonation of dimethyl benzoylphosphonate is the P=O oxygen, and that protonation at this site is followed by C-P bond breaking, with zero energy of activation, leading to dimethyl phosphite and benzoylium cation.
- Breuer, Eli,Karaman, Rafik,Goldblum, Amiram,Leader, Haim
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p. 2029 - 2034
(2007/10/02)
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- Reaction of Arenesulphonyl Halides with Free Radicals. Part 3.
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The decomposition of azoisobutyronitrile (AIBN) and t-butyl phenylperacetate in the presence of toluene-p-sulphonyl bromide and iodide were studied; results are explained on the basis of free radical reactions.The relative reactivities of several alkane- and arene-sulphonyl chlorides towards phenyl, benzyl, and trichloromethyl radicals were measured in competition experiments.Results are rationalized on the grounds of a balance between polar effects in the initial and in the transition state.
- da Silva Correa, Carlos M.M.,Oliveira, Maria Augusta B.C.S.
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p. 811 - 814
(2007/10/02)
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- SELENOSULFONATION OF ALLENES
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Se-Phenyl p-tolueneselenosulfonate (1a) undergoes highly regioselective, photoinitiated freeradical addition to allenes (R1CH=C=CR2R3) to afford the regioisomer R1CH(SePh)C(SO2Ar)=CR2R3 (13) arising from addition to the p-tolylsulfonyl group to the central carbon of the allene and transfer of the phenylseleno group to the less highly substituted of the two terminal carbons.This regioselectivity, which contrasts with that observed in the majority of radical additions to allenes, can be explained by reference to concepts proposed by Heiba as being important in determining the orientation in different radical additions to allenes.Oxidation of the PhSe group in 13 to PhSe(O) gives allylic selenoxides that undergo a reaction sequence of facile, concerted, -sigmatropic rearrangement followed by hydrolysis of the resulting selenenate to afford β-tolylsulfonyl-substituted allylic alcohols, R1CH=C(SO2Ar)C(OH)R2R3 (14) in 70-98percent yield.Photoaddition of 1a to allenes, followed by the conversion of 13 to 14 thus provides a simple, highyield route to a wide variety of 14, a class of compounds that would seem to have a number of interesting possible uses in synthesis.
- Kice, John L.,Kang, Young-Hee
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p. 4739 - 4746
(2007/10/02)
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- 1,3,2,5-DIOXADITHIAZINE 2,2,4,4-TETROXIDES. MOLECULAR STRUCTURE AND DIRECTION OF RING OPENING
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The structure of 1,3,2,4,5-dioxadithiazine 2,2,4,4-tetroxides (R = CCl3, C6H5, p-NO2C6H4), obtaind by the reaction of nitriles with sulfur trioxide, was established by x-ray crystallographic analysis.The effect of substituents R in the tetroxide on the structural characteristics of the heterocycles was investigated.Conditions were found which secure the formation of the tetroxides in the reaction of sulfur trioxide with nitriles containing readily sulfonated groups .The correspondence between the structural characteristics of the tetroxides and the direction of opening was demonstrated.
- Michurin, A. A.,Bel'skii, V. K.,Zhivoderov, A. V.,Bodrikov, I. V.
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p. 1872 - 1880
(2007/10/02)
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- Reaction of Arenesulphonyl Halides with Free Radicals. Part 2
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The generation of arenesulphonyl radicals by halogen abstraction from arenesulphonyl bromides and iodides is described.The relative reactivities of halogen abstraction by phenyl, 1-cyano-1-methylethyl, and benzyl radicals in benzene solution at 60 deg C are reported.These relative reactivities are almost independent of the nature of the substituents on the benzene ring of ArSO2Br.Sulphonyl iodides are more reactive towards phenyl radicals than bromides which in turn are more reactive than the corresponding chlorides (relative reactivities 602:192:1).
- Correa, Carlos M. M. da Silva,Oliveira, Maria Augusta B. C. S.
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p. 711 - 716
(2007/10/02)
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- REACTION OF ALKYL ARENESULFONATES WITH LIQUID SULFUR TRIOXIDE AND AROMATIC HYDROCARBONS
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The reaction of sulfur trioxide with methyl 4-toluenesulfonate leads to the formation of p-CH3C6H4SO2(OSO2)nOCH3 (n=1,2) compounds.Investigation of the composition of the products from the reaction of this mixture with aromatic hydrocarbons showed that the diaryl sulfones in this case are formed by a pyrosulfonate mechanism.The optimum conditions for the synthesis of diaryl sulfones were selected.
- Moskvichev, Yu. A.,Shapiro, Yu E.,Kramerova, S. K.,Sizyk, L. A.,Shutova, I.V.,et al.
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p. 284 - 289
(2007/10/02)
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- Se-Phenyl Areneselenosulfonates: Their Facile Formation and Striking Chemistry
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Benzeneseleninic acid reacts rapidly at 0 deg C with aromatic sulfinic acids according to the stoichiometry of eq 3 to form Se-phenyl arenesulfonates, PhSeSO2Ar (2), in high yield.In contrast to thiosulfonates, PhSSO2Ar, areneselenosulfonates are extremely photosensitive and undergo quite rapid photodecomposition.The principal products of this photodecomposition are the sulfonic anhydride, ArSO2OSO2Ar, and diphenyl diselenide.In the presence of added alkenes the facile photodissociation of 2 can be used to initiate a free-radical chain reaction that results in the addition of 2 to the alkene to form β-phenylseleno sulfones in good yield.The β-phenylseleno sulfones can be converted to synthetically useful α,β-unsaturated sulfones by oxidation of the β-phenylseleno group to the corresponding selenoxide and subsequent elimination of PhSeOH.Photoaddition of 2 to 2,5-norbornadiene to 5-(phenylseleno)-exo-3-nortricyclyl aryl sulfone as the almost exclusive product, while photoaddition to 1,5-cyclooctadiene gives a mixture of approximately equal amounts of the 1,2-adduct, 5-(phenylseleno)-6-arenesulfonyl-1-cyclooctene, and the product of transannular addition, 6-(phenylseleno)-exo-2-arenesulfonyl-cis-bicyclooctane.Besides their extraordinary ease of photodissociation, compounds 2 also react extremely readily with nucleophiles: Nu- + PhSeSO2Ar -> PhSeNu + ArSO2-.Kinetic studies show that the reactivity of PhSeSO2Ar with cyanide ion in such a reaction is 70000 times larger than the reactivity of the corresponding thiosulfonate, PhSSO2Ar.
- Gancarz, Roman A.,Kice, John L.
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p. 4899 - 4906
(2007/10/02)
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- PHOTODECOMPOSITION OF SELENOSULFONATES AND THEIR FACILE PHOTOADDITION TO ALKENES1
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Phenyl areneselenosulfonates (1) are very photosensitive and easily undergo photodecomposition via initial homolysis of the Se-S bond.In the presence alkenes this facile photodissociation of 1 can be used to initiate a free radical chain reaction (eq 6) that leads to addition of 1 to the alkene to form β-phenylselenosulfones (2).The photoaddition requires much shorter reaction times than the non-photolytic addition of 1 to alkenes described recently.
- Gancarz, Roman A.,Kice, John L.
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p. 4155 - 4158
(2007/10/02)
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- THERMOLYSE VON DIARYLDISULFIDTRIOXIDEN
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Diaryldisulfidetrioxides-otherwise designated as sulfinic acid anhydrides-decompose at their melting point yielding disulfide, thiolsulfinate, and sulfonic acid anhydride.The stoichiometry of the decomposition is determined, and a reaction mechanism is discussed.
- Schank, Kurt,Werner, Frank
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p. 335 - 336
(2007/10/02)
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