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Biocatalytic desulfurization of arylsulfonates.

A microbial strain, Klebsiella oxytoca KS3D, has been isolated which is capable of exploiting arylsulfonates as a sole source of sulfur during growth. The desulfurization catalyzed by intact K. oxytoca KS3D results in the conversion of arylsulfonates into the corresponding phenols. Even arylsulfonates carrying substituents which significantly alter steric and electronic characteristics are substrates. Only a single regioisomer is produced from substituted arylsulfonates. Based on the products formed from the biocatalytic desulfurizations and incorporation of isotopic oxygen in phenolic product when the desulfurization is run under 18O-enriched oxygen, hydrolysis mechanisms can be eliminated from consideration. Two reaction types which might mimic the chemistry occurring during microbial desulfurization of arylsulfonates were examined. The first reaction involved conversion of appropriately substituted arylsulfonates into phenols by single electron reduction followed by reaction of the radical anions with molecular oxygen. A second reaction using intramolecular reaction of arylsulfonates and arylsulfones with alkoxy radicals failed to achieve desulfurization. In addition to mechanistic evaluation, desulfurization of arylsulfonates catalyzed by K. oxytoca KS3D is examined from the perspective of its relevance to desulfurization of the organosulfur components of coal and its possible use for industrial manufacture of phenols.

Arylsulfonates↗

Formation of drug-arylsulfonate complexes inside liposomes: a novel approach to improve drug retention.

The development of procedures to enhance drug retention in liposomes is important in order to achieve therapeutically optimized rates of drug release from liposomal carriers. In this study, the ability of lipophilic weak base drugs to complex with arylsulfonates resulting in formation of intravesicular precipitates is investigated as a means to enhance drug retention. It is shown that the arylsulfonates benzenesulfonate and hydroxybenzenesulfonate (HBS) induce precipitation of ciprofloxacin and vinorelbine, two representative weak base drugs that are difficult to retain in liposomal systems. The most complete precipitation was observed at pH values corresponding to charge neutralization of the drug-arylsulfonate complex. HBS is shown to be a much more effective precipitating agent than benzenesulfonate. It is also shown that vinorelbine and ciprofloxacin can be loaded into large unilamellar vesicles (LUV) containing the calcium salt of HBS using an ionophore-based loading method. Following drug loading, the formation of intravesicular drug-arylsulfonate precipitates of vinorelbine and ciprofloxacin was observed by cryo-electron microscopy. In vitro release experiments showed substantial improvements in drug retention for both vinorelbine and ciprofloxacin when HBS was present as compared to standard loading procedures employing MgSO4 as the entrapped solute. In vivo release experiments for vinorelbine in NuNu mice indicated a half-time for release for HBS-containing LUV of approximately 30 h, compared to 6.4 h for LUV loaded employing MgSO4. It is suggested that encapsulation procedures employing HBS in the internal medium can improve the retention of drugs that are difficult to retain in liposomes, possibly leading to enhanced therapeutic properties.

Animals↗

Antiviral properties of new arylsulfone derivatives with activity against human betaherpesviruses.

Based on our previous experience with arylsulfone derivatives displaying antiherpetic activity, we synthesized several analogues in which the sulfonyl group is part of a bicyclic structure. The benzene-fused derivative 2H-3-(4-chlorophenyl)-3,4-dihydro-1,4-benzo-thiazine-2-carbonitrile 1,1-dioxide and its thiophene-fused analogue were shown to have favorable activity and selectivity against the betaherpesviruses human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6) and 7 (HHV-7). The benzene-fused derivative retained its anti-HCMV activity when evaluated against virus strains resistant to foscarnet, ganciclovir, and/or cidofovir. The compound conferred >or=95% inhibition of viral DNA synthesis in HHV-6-infected cells. RT-PCR analysis of immediate-early, early and late gene products revealed that this arylsulfone compound acts at a step preceding late gene expression, and coinciding with the inhibition exerted by foscarnet. No inhibitory effect was seen in an enzyme assay for DNA elongation catalyzed by the HCMV or HHV-6 DNA polymerase catalytic subunit. The arylsulfone derivatives had no effect on the functional interaction between the catalytic subunit of HCMV DNA polymerase and its accessory protein, nor did they disrupt the physical interaction between the two proteins. We conclude that these arylsulfone derivatives represent new betaherpesvirus inhibitors with a novel mode of action that results in indirect inhibition of viral DNA synthesis.

Antiviral Agents↗

Arylsulfonates as sole source of sulfur for Clostridium pasteurianum DSM 12136.

A variety of arylsulfonates were examined for their ability to support growth of Clostridium pasteurianum as sole source of sulfur. Among the eleven different arylsulfonates tested, six of them (benzenesulfonate, 4-toluenesulfonate, 4-xylene-2-sulfonate, 4-aminobenzenesulfonate, 4-sulfobenzoic acid, 1,3-benzenedisulfonate) could serve as sole sulfur source for C. pasteurianum DSM 12136. None of the sulfonates tested could serve as sole sulfur source for C. pasteurianum ATCC 6013. The two C. pasteurianum in this study could not utilize any of these sulfonates as sole carbon and energy source. We demonstrated that desulfonation of arylsulfonates could take place under anoxic conditions and the sulfur atom of these compounds could be utilized as sole source of sulfur by anaerobic bacteria.

Arylsulfonates↗

Mild and room temperature C-C bond forming reactions of nucleoside C-6 arylsulfonates.

[reaction: see text] Palladium catalyzed cross coupling of nucleoside arylsulfonates and arylboronic acids has been accomplished under mild conditions and at room temperature. Among three structurally similar ligands that differ in their steric and electronic properties, one yielded an effective catalyst in conjunction with Pd(OAc)2. Of the nucleoside arylsulfonates evaluated, the O6-(2,4,6-trimethylphenyl)sulfonate proved optimal, but other alkyl and alkoxy derivatives were also reasonably reactive. On the other hand, a 2-nitrophenyl and a 2-thienyl derivative were ineffective substrates. PhMe and THP were suitable as solvents, yielding good results in several cases, although reactions of some arylboronic acids were faster in PhMe. In contrast, reactions of arylboronic acids bearing strongly electron-withdrawing groups proceeded more successfully in THP. Interplay between several factors that include substituents on the nucleoside arylsulfonate, ligand substituents, and solvent is responsible for successful cross coupling. Using 31P NMR, an initial investigation has been conducted to study the interaction of Pd(OAc)2 with the ligand. At a 1:1 stoichiometry of ligand and Pd(OAc)2, a predominant species, likely a cyclopalladation product, was obtained. At a 2:1 ratio of ligand and Pd(OAc)2, a different species bearing chemically distinct phosphine ligands was observed. Both complexes display catalytic activity, although the 2:1 species may be superior.

Arylsulfonates↗

Assimilation of sulfur from alkyl- and arylsulfonates by Clostridium spp.

Organisms able to utilize one of several alkyl- and arylsulfonates as sole source of sulfur under anoxic conditions were enriched. Three fermenting bacteria, all putative Clostridium spp., were isolated in pure culture. All three organisms had wide substrate ranges for alkylsulfonates, taurine and arylsulfonates, presumably due to three different enzyme systems. One organism, strain KNNDS (DSM 10612) was selected for further characterization. The organism was possibly a new Clostridium sp., with Clostidium intestinalis as its nearest neighbor (97.6% similarity of rDNA). Strain KNNDS catalyzed complete sulfonate utilization concomitant with growth. Growth yields of approximtely 3 kg protein/mol sulfur were observed, independent of the sulfur source [e.g. sulfate, sulfide, 4-(phenyl)butyl-1-sulfonate, 2,6-naphthyldisulfonate or 4-nitrocatechol sulfate]. We failed to detect significant amounts of either an arylsulfonatase or an arylsulfatase, and we hypothesize different arylsulfatases [EC 3.1.6.1] in aerobes and in Clostridium spp.

Alkanesulfonates↗

Arylsulfonate esters as hypocholesteremic agents: III. Mechanism of action studies.

The mechanism responsible for the hypocholestermic action of arylsulfonate esters of long chain fatty alcohols has been studied with rats fed either normocholesteremic or hypercholesteremic (1% cholesterol plus 0.5% glycoholate) diets. Linoleyl tosylate is more effective in lowering plasma and liver cholesterol levels of rats on the hypercholesteremic diet than several other hypocholesteremic agents tested. Linoleyl tosylate does not redistribute cholesterol to extrahepatic tissues nor inhibit hepatic cholesterol biosynthesis. Linoleyl tosylate is not effective in counteracting Triton-induced hypercholesteremia nor in lowering plasma cholesterol levels of the suckling rat. Linoleyl tosylate increases the fecal elimination of dietary [4(-14)C] cholesterol and prevents its accumulation in blood and liver. Oleyl p-(n-decyl) benzene sulfonate also prevents the apparent absorption of [26(-14)C] cholesterol from the gastrointestinal tract. Linoleyl tosylate increases the fecal excretion of neutral sterols but not of bile acids. The results indicate that the arylsulfonate esters of long chain fatty alcohols lower body cholesterol levels by inhibiting cholesterol absorption from the gastrointestinal tract. Exactly how absorption is inhibited is not clear, but linoleyl tosylate was found to stimulate the activity of cholesteryl esterase prepared from the intestinal mucosa.

Animals↗

The effect of arylsulfonate esters on cholesterol--aggravated atherosclerosis in White Carneau Pigeons.

The arylsulfonate esters of linoleyl, stearyl, and decyl alcohols were found to reduce significantly the accumulation of cholesterol in the plasma and livers of White Carneau pigeons subjected to a diet of Purina pigeon pellets coated with 0.25% cholesterol and 10% lard when fed for periods ranging from 9--12 months; no effects were observed in normocholesterolemic pigeons. These compounds produced no toxic side effects and were found to significantly attenuate the development of aortic atherosclerosis. The effect on aortic atherosclerosis was most likely the result of the lowering of plasma cholesterol concentrations. Linoleyl p-toluenesulfonate appeared to be the most effective of the three arylsulfonates tested, both with respect to the reduction of plasma and liver cholesterol accumulation and attenuation of the atherosclerotic process.

Animals↗

Arylsulfonate-based nucleophile assisting leaving groups.

[Chemical reaction: See text] The synthesis and unique reactivity of a series of arylsulfonate-based nucleophile assisting leaving groups (NALG) containing oligomeric ether units (including crown ethers) attached to the arylsulfonyl ring in the ortho orientation are described. The reactions of a variety of these ether-containing alkyl sulfonates with metal halides proceeded at substantially greater rates than electronically similar sulfonates. These ether-containing leaving groups also displayed marked selectivity for lithium halides relative to the corresponding sodium and potassium salts in nucleophilic displacement reactions.

Arylsulfonates↗

Arylsulfonate esters of fatty alcohols as hypocholesterolemic agents. I: Oleyl and linoleyl p-toluenesulfonates.

Cholesterol levels of both plasma and liver of cholesterol-fed rats are lowered by feeding linoleyl and oleyl esters of p-toluenesulfonic acid. A structural specificity exists, since the effect is not observed with similar amounts of sodium p-toluenesulfonate nor with linoleyl methanesulfonate. Effective levels of these arylsulfonates do not alter liver to body weight ratios and maturation, nor reduce plasma cholesterol in normocholesterolemic rats.

Animals↗

2D and 3D supramolecular structures via hydrogen bonds and pi-stacking interactions in arylsulfonates of nickel and cobalt.

Five novel arylsulfonates of Ni and Co have been hydrothermally obtained and their structures determined by X-ray single-crystal diffraction. [Ni(Phen)(H2O)](1,5-NDS).2H2O (1) is a hydrogen-bonded supramolecular layered compound formed by self-assembly of tetraaqua-o-phenanthrolinenickel(II) cations and 1,5-naphthalenedisulfonate anions, [Ni(Phen)2(H2O)(1,5-NDS)] (2) and [Ni(Phen)2(H2O)(2,6-NDS)].2H2O (4) exhibit 2D structures via O-H...O and pi-pi (both perfect face-to-face and parallel-displaced) stacking interactions, [Co(Phen)2(H2O)(1,5-NDS)].2H2O (5) presents a 3D structure via O-H...O hydrogen-bond layers and pi-pi parallel-displaced stacking interactions, and [Co(Phen)2(1,5-NDS)] (3) is the first example of a covalently bonded polymeric cobalt sulfonate. Its 1D structure comprises chains formed through bitopic 1,5-NDS linkers. Rates and selectivities for oxidation of organic sulfides with H2O2 were measured with 2-5.

Journal Article↗

Photochemical surface modification of poly(arylsulfone) ultrafiltration membrane and covalent immobilization of enzyme.

The sensitivity of poly(arylsulfone) (PSf) for UV irradiation in different solvents (water and ethanol) was investigated. It is confirmed that acrylic acid (AA) and acrylamide (AAm) are grafted only onto the surface of the membrane instead of the interior by FTIR and scanning electron microscope (SEM). The membrane performance (deltaJ/J0 and contact angle theta) after photografting was studied. In the range of conditions used, the grafting yield increases with irradiation time and monomer concentration growing. After photografting and N-3-dimethylaminopropyl-N'-ethycarbodiimide hydrochloride (EDC) activation, PSf membrane was immobilized with hydrogen peroxide oxidoreductase, and showed a higher activity than the control membrane.

Filtration↗

Conjugative plasmids and the degradation of arylsulfonates in Comamonas testosteroni.

Comamonas testosteroni T-2 degrades p-toluenesulfonate (TSA) via p-sulfobenzoate (PSB) and protocatechuate and degrades toluenecarboxylate via terephthalate (TER) and protocatechuate. The appropriate genes are expressed in at least five regulatory units, some of which are also found in C. testosteroni PSB-4 (F. Junker, R. Kiewitz, and A. M. Cook, J. Bacteriol. 179:919-927, 1997). C. testosteroni T-2 was found to contain two plasmids, pTSA (85 kbp) and pT2T (50 kbp); a TSA- mutant (strain TER-1) contained only plasmid pT2T. C. testosteroni PSB-4, which does not degrade TSA, contained one plasmid, pPSB (85 kbp). The type strain contained no plasmids. Conjugation experiments showed that plasmid pTSA (possibly in conjunction with pT2T) was conjugative, and the single copy of the TSA operon (tsaMBCD) with its putative regulator gene (tsaR) in strain T-2 was found on plasmid pTSA, which also carried the PSB genes (psbAC) and presumably transport for both substrates. Plasmid pTSA was assigned to the IncP1 beta group and was found to carry two copies of insertion element IS1071. Plasmid pPSB (of strain PSB-4), which could be maintained in strains with plasmid pTSA or pT2T, was also conjugative and was found to carry the PSB genes as well as to contain two copies of IS1071. In attempted conjugations with the type strain, no plasmid was recovered, but the PSB+ transconjugant carried two copies of IS1071 in the chromosome. We presume the PSB genes to be located in a composite transposon. The genes encoding the putative TER operon and degradation of protocatechuate, with the meta cleavage pathway, were attributed a chromosomal location in strains T-2 and PSB-4.

Amino Acid Sequence↗

Bacterial metabolism of arylsulfonates: role of meta cleavage in benzene sulfonate oxidation by Pseudomonas testosteroni.

Pseudomonas testosteroni H-8 oxidizes certain lower alkylbenzene sulfonates at rates inversely related to the length of the alkyl group. Appreciable Q(O)2 values were observed for benzene sulfonate (BS), toluene sulfonate (TS), and ethylbenzene sulfonate (EBS), but not for propylbenzene sulfonate (PS) and higher homologues. Catechol oxidation was catalyzed by a constitutive catechol-2,3-oxygenase (EC 1.99.2.a). Yellow meta cleavage products accumulated when BS-grown cells were exposed to catechol, 4-methylcatechol, 3-methylcatechol, EBS and PS, but not BS or TS. Traces of a yellow metabolite (probably 2-hydroxymuconic semialdehyde) were detectable during growth on BS. PS completely inhibited growth on BS, but not on L-leucine or nutrient broth. Also, PS antagonized respiration on BS and catechol, but not glutamate, the extent of inhibition being directly related to PS concentration. Formation of a meta cleavage product from PS, and inhibition of catechol oxidation by PS, suggested that the actual inhibitor may not be PS itself, but a metabolite.

Arylsulfonates↗