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PubMedDate not supplied

Efficient synthesis of sulfonic, phosphoric, and phosphinic esters employing alkylating polymer-bound reagents.

The efficient esterification of various sulfonic acids and sulfonates using polymer-bound triazenes based on the triazene T2 linker is described. Esterification of enantiopure alpha-substituted sodium sulfonates was performed in the presence of an alkylating resin without racemization. Racemization is a serious drawback in the esterification route via sulfonyl chlorides because of intermediate sulfene formation. To demonstrate the versatility of this protocol, phosphoric and phosphinic acids have been converted into the corresponding esters as well. All products were obtained in good yield and excellent purities without any further purification steps.

Journal Article↗
PubMed2002

Leaching and primary biodegradation of sulfonated naphthalenes and their formaldehyde condensates from concrete superplasticizers in groundwater affected by tunnel construction.

Sulfonated naphthalenes and their formaldehyde condensates (SNFC) are used as concrete superplasticizers fortunnel construction through aquifers.This paperdiscusses their primary biodegradation in groundwater affected by construction activities. The analyses of groundwater samples collected 5 m away from a construction site clearly indicated that components of the applied SNFC product leached into the groundwater. A maximum total concentration of these compounds of 233 microg/L was found, and it was shown that only the monomeric sulfonated naphthalenes andthe condensates uptothetetramerleached in substantial amounts. The decrease in concentration of several monomeric components could not be explained by mere dispersion but rather indicates a biological transformation in the aquifer. This was confirmed at a second field site and by laboratory degradation experiments with piezometer material as inoculum. Lag phases for the individually degradable sulfonated naphthalenes ranged from 0 to 96 d. Naphthalene-1,5-disulfonate and the oligomeric components were neither degraded in the aquifer nor in the laboratory experiments within an observation time of up to 195 d. This clearly indicates their persistence in subsurface waters.

Disinfectants↗
PubMed2003

A survey of perfluorooctane sulfonate and related perfluorinated organic compounds in water, fish, birds, and humans from Japan.

Occurrence of perfluorooctane sulfonate (PFOS) in the tissues of humans and wildlife is well documented. In this study, concentrations and distribution of PFOS, perfluorohexane sulfonate (PFHS), and perfluorobutane sulfonate (PFBS) were determined in samples of surface water, fish and bird blood and livers, and human blood collected in Japan. Notable concentrations of PFOS were found in surface water and fish from Tokyo Bay. PFOS was found in all of the 78 samples of fish blood and liver analyzed. Based on the concentrations of PFOS in water and in fish livers, bioconcentration factors were calculated to range from 274 to 41 600. Concentrations of PFOS in the blood of Japanese human volunteers ranged from 2.4 to 14 ng/mL. PFHS was detected in 33% of the fishes analyzed, at concentrations severalfold less than those of PFOS.

Alkanesulfonic Acids↗
PubMed2005

An investigation on the role of the nature of sulfonate ancillary ligands on the strength and concentration dependence of the second-order NLO responses in CHCl3 of Zn(II) complexes with 4,4'-trans-NC5H4CH=CHC6H4NMe2 and 4,4'-trans,trans-NC5H4CH=CH)2C6H4NMe2.

To evidentiate the role of the nature of sulfonate ancillary ligands on the value of the quadratic hyperpolarizability of Zn(II) complexes with stilbazole-like ligands, the second-order nonlinear optical (NLO) properties of [ZnY(2)(4,4'-trans-NC5H4CH=CHC6H4NMe2)2] complexes (Y = CF3SO3, CH3SO3, or p-CH3C6H4SO3) are investigated. By working at relatively high concentrations (>3 x 10(-4) M), the positive effect of the triflate ligand remains unique while, with nonfluorinated sulfonate ligands, the second-order NLO response is comparable to that of the related complexes with acetate or trifluoroacetate as ancillary ligands. However, at dilutions higher than 10(-4) M, all of the sulfonate complexes reach huge quadratic hyperpolarizabilities because of solvolysis with the formation of cationic species such as [ZnY(4,4'-trans-NC5H4CH=CHC6H4NMe2)2]+, characterized by a large second-order NLO response. This view is supported by careful conductivity measurements. The same behavior occurs if 4,4'-trans-NC5H4CH=CHC6H4NMe2 is substituted by 4,4'-trans,trans-NC5H4(CH=CH)2C6H4NMe2.

Journal Article↗
PubMed2002

Asymmetric induction in the Neber rearrangement of simple ketoxime sulfonates under phase-transfer conditions: experimental evidence for the participation of an anionic pathway.

Phase-transfer catalysis has been successfully utilized for the Neber rearrangement of simple ketoxime sulfonates. For instance, treatment of (Z)-1a with p-toluenesulfonyl chloride (1.2 equiv), tetrabutylammonium bromide (5 mol %) and MeOH (10 equiv) in toluene-50% KOH aqueous solution (volume ratio = 3:1) at 0 degrees C for 2 h, and subsequent benzoylation followed by acidic hydrolysis afforded the protected alpha-amino ketone 2a in 80% isolated yield. On the basis of this finding, asymmetric Neber rearrangement with ketoxime (Z)-1a was examined under phase-transfer conditions using structurally rigid, C(2)-symmetric chiral quaternary ammonium bromide 3 as catalyst. The desired 2a was obtained in 80% yield and 51% ee. This represents the first experimental demonstration of the substantial involvement of anion pathway in the Neber rearrangement of simple ketoxime sulfonates. Importantly, the reaction with (E)-1a under otherwise similar conditions afforded racemic 2a in 61% yield. Moreover, enhanced enantioselectivity (63% ee) was observed in the rearrangement of the oxime sulfonate derived from (Z)-1b, and notably, use of mesitylene in place of toluene further increased the enantioselectivity to 70% ee. Our approach provides not only a new mechanistic insight but also an opportunity for extending the full synthetic utility of this classical yet useful rearrangement.

Alkanesulfonates↗
PubMed1989

Synthesis of 2,3-diaziridinyl-1,4-naphthoquinone sulfonate derivatives as potential antineoplastic agents.

A new class of 2,3-diaziridinyl-1,4-naphthoquinone sulfonates (27 compounds) has been synthesized and evaluated as potential antineoplastic agents. The most active compounds, benzenesulfonate 4, p-toluenesulfonate 5, p-methoxybenzenesulfonate 7,8-quinolinesulfonate 17, and 2-thiophenesulfonate 20, in the aromatic sulfonate series, at their optimum daily dosage level of 25 mg/kg X 6, produced 100%, 90%, 75%, 80%, and 100% 50-day survivors, respectively, of L1210 tumor-bearing mice. At a lower optimum daily dosage level of 20 mg/kg X 6, treatments with p-fluorobenzenesulfonate 11 and p-nitrobenzenesulfonate 15 resulted in 100% and 80% 50-day survivors. In the aliphatic sulfonate series, methanesulfonate 21 produced 80% 50-day survivors at a 10 mg/kg daily dosage level X 6. Benzenesulfonate 4, p-fluorobenzenesulfonate 11, 8-quinolinesulfonate 17, and 2-thiophenesulfonate 20 derivatives were also tested in mice bearing the B16 melanoma; these agents gave T/C X 100 values of 180, 182, 219, and 161, respectively, in this neoplastic cell system. Structure-activity relationships of compounds of this class are discussed.

Animals↗
PubMed1981

Anticoccidial derivatives of 6-azauracil. 4. A 1000-fold enhancement of potency by phenyl sulfide and phenyl sulfone side chains.

We report further progress in exploiting our earlier discovery that the anticoccidial activity of 6-azauracil increases markedly when appropriately substituted benzyl or phenyl groups are attached at N-1. With guidance from previous structure-activity relationships and a multiple linear regression analysis, 6-azauracils containing phenyl sulfone or phenyl sulfide side chains were prepared. These prevented a broad spectrum of coccidial infections in chickens at minimum inhibitory concentrations by weight in feed as low as 0.25 ppm, a 4000-fold increase in potency over 6-azauracil, and had shorter plasma half-lives than earlier potent analogues. Sulfides were more potent than sulfones, although they were oxidized rapidly to sulfones in vivo.

Animals↗
PubMed1996

Design, synthesis, and evaluation of 2 beta-alkenyl penam sulfone acids as inhibitors of beta-lactamases.

A general method for synthesis of 2 beta-alkenyl penam sulfones has been developed. The new compounds inhibited most of the common types of beta-lactamase. The level of activity depended very strongly on the nature of the substituent in the 2 beta-alkenyl group. The inhibited species formed with the beta-lactamase from Citrobacter freundii 1205 was sufficiently stable for X-ray crystallographic studies. These, together with UV absorption spectroscopy and studies of chemical degradation, suggested a novel reaction mechanism for the new inhibitors that might account for their broad spectrum of action. The (Z)-2 beta-acrylonitrile penam sulfone Ro 48-1220 was the most active inhibitor from this class of compound. The inhibitor enhanced the action of, for example, ceftriaxone against a broad selection of organisms producing beta-lactamases. The organisms included strains of Enterobacteriaceae that produce cephalosporinases, which is an exceptional activity for penam sulfones.

Ceftriaxone↗
PubMed2000

A convenient new route to piperidines, pyrrolizidines, indolizidines, and quinolizidines by cyclization of acetylenic sulfones with beta and gamma-chloroamines. Enantioselective total synthesis of indolizidines (-)-167B, (-)-209D, (-)-209B, and (-)-207A.

The methyl esters of (L)-phenylalanine and (L)-methionine underwent conjugate additions via their free amino groups to 1-(p-toluenesulfonyl)hexyne, followed by intramolecular acylation of the corresponding enamide anions and tautomerization to afford 2-benzyl-5-n-butyl-3-hydroxy-4-(p-toluenesulfonyl)pyrrole and 5-n-butyl-3-hydroxy-2-(2-methylthioethyl)-4-(p-toluenesulfonyl)pyr role, respectively. The conjugate additions of a series of acyclic and cyclic secondary beta- and gamma-chloroamines to acetylenic sulfones proceeded similarly under mild conditions. The resulting adducts were deprotonated with LDA in THF at -78 degrees C, and the resulting sulfone-stabilized carbanions underwent intramolecular alkylation to afford cyclic enamine sulfones. Thus, acyclic gamma-chloroalkyl-benzylamines afforded the corresponding 2- or 2,6-disubstituted piperidines, while 2-(chloromethyl)pyrrolidines, 2-(2-chloroethyl)pyrrolidines, 2-(chloromethyl)piperidines, and 2-(2-chloroethyl)piperidines produced the corresponding 3-substituted pyrrolizidines, 5- or 3-substituted indolizidines, and 4-substituted quinolizidines, respectively. 8-Methyl-5-substituted indolizidines were also prepared from the appropriate methyl-substituted chloroamine precursor. Enantioselective syntheses were achieved by employing chiral chloroamines derived from amino acids or other enantiopure precursors. Further transformations of several of the products provided concise syntheses of four dendrobatid alkaloids. Thus, reduction of (8aS)-5-n-propyl-6-(p-toluenesulfonyl)-delta5,6-indolizidine with sodium cyanoborohydride in trifluoroacetic acid, followed by reductive desulfonylation, afforded (-)-indolizidine 167B. The corresponding 5-n-hexyl derivative similarly produced (-)-indolizidine 209D, while (-)-(8R, 8aS)-8-methyl-5-n-pentyl-6-(p-toluenesulfonyl)-delta5,6-indo lizidine furnished (-)-indolizidine 209B. Finally, the similar reduction and debenzylation of (-)-(8R,8aS)-5-(2-benzyloxyethyl)-8-methyl-6-(p-toluenesulfo nyl)-delta5,6-indolizidine produced the corresponding 5-hydroxyethyl indolizidine. This was subjected to chlorination of the alcohol group with thionyl chloride and substitution with a higher order allyl cuprate reagent to afford (-)-indolizidine 207A.

Acylation↗
PubMed2001

Vinyl sulfones in solid-phase synthesis: preparation of 4,5,6,7-tetrahydroisoindole derivatives.

The preparation of functionalized 4,5,6,7-tetrahydroisoindole via a traceless solid-phase sulfone linker strategy is described. Thermolytic extrusion of SO(2) from polymer-bound 3-(phenylsulfonyl)-3-sulfolene (7) generated polymer-bound 2-(phenylsulfonyl)-1,3-butadiene (9) in situ which underwent Diels--Alder cycloaddition with various dienophiles to furnish vinyl sulfone resins 10-14. To complete a traceless linker cleavage strategy, (p-tolysulfonyl)methyl isocyanide or ethyl isocyanoacetate was employed to react with the vinyl sulfone moiety to liberate functionalized 4,5,6,7-tetrahydroisoindole products from the resin. Using this chemistry, nine tetrahydroisoindole derivatives (6, 15-22) were prepared in 32-41% overall yields from polystyrene/divinylbenzene sulfinate 1.

Journal Article↗
PubMed2002

The first example of a singlet oxygen induced double bond migration during sulfide photooxidation. Experimental evidence for sulfone formation via a hydroperoxy sulfonium ylide.

The first example of the formation of a sulfone concomitant with double bond migration during photooxidation of a sulfide is reported. Evidence is presented which demonstrates that the double bond migration is not a result of a prior acid-catalyzed rearrangement of an unrearranged sulfone precursor. This unusual observation is used to argue that the sulfone is formed via rearrangement of a hydroperoxy sulfonium ylide intermediate.

Journal Article↗
PubMed2003

Calorimetric and computational study of thiacyclohexane 1-oxide and thiacyclohexane 1,1-dioxide (thiane sulfoxide and thiane sulfone). Enthalpies of formation and the energy of the S=O bond.

A rotating-bomb combustion calorimeter specifically designed for the study of sulfur-containing compounds [J. Chem. Thermodyn. 1999, 31, 635] has been used for the determination of the enthalpy of formation of thiane sulfone, 4, Delta(f)H(o) m(g) = -394.8 +/- 1.5 kJ x mol(-1). This value stands in stark contrast with the enthalpy of formation reported for thiane itself, Delta(f)H(o) m(g) = -63.5 +/- 1.0 kJ x mol(-1), and gives evidence of the increased electronegativity of the sulfur atom in the sulfonyl group, which leads to significantly stronger C-SO2 bonds. Given the known enthalpy of formation of atomic oxygen in the gas phase, Delta(f)H(o) m(O,g) = +249.18 kJ x mol(-1), and the reported bond dissociation energy for the S=O bond in alkyl sulfones, BDE(S=O) = +470.0 kJ x mol(-1), it was possible to estimate the enthalpy of formation of thiane sulfoxide, 5, a hygroscopic compound not easy to use in experimental calorimetric measurements, Delta(f)H(o) m(5) = -174.0 kJ x mol(-1). The experimental enthalpy of formation of both 4 and 5 were closely reproduced by theoretical calculations at the G2(MP2)+ level, Delta(f)H(o) m(4) = -395.0 kJ x mol(-1) and Delta(f)H(o) m(5) = -178.0 kJ x mol(-1). Finally, calculated G2(MP2)+ values for the bond dissociation energy of the S=O bond in cyclic sulfoxide 5 and sulfone 4 are +363.7 and +466.2 kJ x mol(-1), respectively.

Journal Article↗
PubMed2002

The sulfone linker in solid-phase synthesis: preparation of 3,5-disubstituted cyclopent-2-enones.

The preparation of functionalized 3,5-disubstituted cyclopent-2-enones via a solid-phase sulfone linker strategy is described. Polystyrene/divinylbenzene sulfinate 1 underwent S-alkylation followed by alpha,alpha-dialkylation with cis-1,4-dichloro-2-butene to form polymer-bound 3-phenylsulfonylcyclopentenes 8. Subsequent epoxidation of the cyclopentene moiety in 8 was accomplished by treatment of mCPBA, and the resulting oxirane ring in resin 9 was opened with various nucleophiles, i.e., Grignard and cuprate reagents, azide ion, and amines. To complete the sulfone-based linker strategy, Swern or TPAP oxidation of 10 gave a transient gamma-ketosulfone, which underwent sulfinate elimination, thus cleaving the sulfone linker. Eleven 3,5-disubstituted cyclopent-2-enones (11) were prepared with this five-step process in 18-40% overall yield from solid-phase benzene sulfinate 1.

Journal Article↗
PubMed2003

Conformational analysis: crystallographic, NMR, and molecular mechanics studies of flexible sulfonic esters.

Two novel X-ray structures of the sulfonic ester derivatives 2-(6-iodo-1,3-benzodioxol-5-yl)ethyl 4-nitrobenzenesulfonate, 3, and 2-(6-iodo-1,3-benzodioxol-5-yl)ethyl 4-methylbenzenesulfonate, 4, have been obtained in a study aimed at analyzing the structures and conformations of sulfonic ester derivatives that are routinely used in alkaloid syntheses. The crystal structure of 4 is highly unusual, containing four independent molecules that belong to two distinct conformational types: (1) a hairpin conformation (stabilized mainly by intramolecular pi-stacking) and (2) a stepped conformation (stabilized mainly by intermolecular pi-stacking). Compound 3, on the other hand, crystallizes exclusively as the hairpin conformer. New MM+ force field parameters for sulfonic esters have been developed using the X-ray data, empirical rules, and DFT calculations to estimate the bond dipole parameters. Grid searches of conformational space for 3 and 4 using MM methods show that there are several gas-phase conformations within 5 kcal/mol of the global minimum and that the lowest energy conformations (by approximately 4.6 kcal/mol) are of the hairpin type. Analysis of the MM conformational energies suggests that the dominant intramolecular interaction stabilizing the hairpin conformations of 3 and 4 is van der Waals attraction. Moreover, the lattice energies for packing the hairpin conformations of 3 and 4 are approximately 4 kcal/mol more favorable than for the stepped conformations. Various intermolecular interactions contribute to the complexity of the observed crystal structures of 3 and 4, including electrostatic attraction between O and I atoms in neighboring molecules. Langevin dynamics (LD) simulations at several temperatures (6.0 ns, friction coefficient = 2.5 ps(-1)) indicate that the conformational exchange rates are approximately 10(10)-10(11) s(-1) over the temperature range 213-400 K, accounting for the temperature-independent (1)H NMR spectra of 3 and 4.

Journal Article↗
PubMed2003

Chromium(VI) oxide catalyzed oxidation of sulfides to sulfones with periodic acid.

A highly efficient and selective oxidation of sulfides to sulfones with periodic acid catalyzed by CrO(3) is described. A variety of electron-rich and electron-deficient sulfides were oxidized to sulfones with 2 mol % CrO(3) in acetonitrile at room temperature in excellent yields. Sulfides with other readily oxidized functional groups were selectively oxidized to sulfones in high yields with 10 mol % CrO(3) in ethyl acetate/acetonitrile at -35 degrees C.

Journal Article↗
PubMed2004

Palladium-catalyzed enantioselective 1,3-rearrangement of racemic allylic sulfinates: asymmetric synthesis of allylic sulfones and kinetic resolution of an allylic sulfinate.

Described is an asymmetric synthesis of cyclic and acyclic allylic S-aryl and S-alkyl sulfones through a highly selective palladium(0)-catalyzed 1,3-rearrangement of racemic allylic sulfinates. Treatment of racemic cyclic and acyclic allylic S-tolyl- and S-tert-butylsulfinates with Pd(2)(dba)(3).CHCl(3) as precatalyst and N,N'-(1R,2R)-1,2-cyclohexanediylbis[2-(diphenylphosphino)benzamide] as ligand for the palladium atom afforded the corresponding isomeric allylic S-tolyl and S-tert-butyl sulfones of 93-99% ee in 82-96% yield. The rearrangement of the allylic sulfinates most likely proceeds in an intermolecular fashion via formation of a cationic pi-allylpalladium complex and the sulfinate ion. The racemic allylic sulfinates were obtained from the corresponding racemic alcohols and racemic tolylsulfinyl chloride and racemic tert-butylsulfinyl chloride, respectively, in high yields. Rearrangement of the racemic tert-butylsulfinic acid 2-cyclooct-1-enyl ester with Pd(2)(dba)(3).CHCl(3) and the bisphosphane was accompanied by a highly selective kinetic resolution of the substrate and gave at 50% conversion the (R)-configured sulfinate as mixture of the S(S) and R(S) diastereomers of 92% ee and 85% ee and the (S)-configured 3-tert-butylsulfonyl cyclooctene sulfone 15a with 98% ee in almost quantitative yields.

Journal Article↗
PubMed2004

Sulfur dioxide mediated one-pot, three- and four-component syntheses of polyfunctional sulfonamides and sulfonic esters: study of the stereoselectivity of the ene reaction of sulfur dioxide.

The ene reaction of sulfur dioxide with enoxysilanes or with allylsilanes generates silyl sulfinates that can be brominated (Br(2) or NBS) or chlorinated (NCS or Cl(2)) to produce the corresponding sulfonyl halides. They react with primary and secondary amines or alcohols to give the corresponding sulfonamides and sulfonic esters, respectively. The hetero-Diels-Alder addition of sulfur dioxide to 1-oxy- or 1,3-dioxy-1,3-dienes generates zwitterions that add to enoxysilanes or allylsilanes giving silyl sulfinates that can be converted in situ into polyfunctional sulfonamides or sulfonic esters. This realizes quick access to libraries of complicated sulfonamides and sulfonic esters applying one-pot, three- and four-component methods.

Journal Article↗
PubMed2005

Chemical force titrations of amine- and sulfonic acid-modified poly(dimethylsiloxane).

Chemical force titrations-measurements of the adhesive interaction between a pair of suitably chemically modified atomic force microscopy (AFM) tip and sample surfaces as a function of pH-have been carried out for various combinations of silanol, amine, carboxylic acid, and sulfonic acid functional groups on both tip and sample. The primary surface material studied was poly(dimethylsiloxane) (PDMS). Surface modification was carried out using a plasma oxidation process to form silanol sites; further modification with amine or sulfonic acid sites was carried out by reaction of the silanol sites with the appropriate trialkoxysilane derivative. AFM tips were also modified using trialkoxysilane compounds. In the cases of tip/sample combinations with the same functional group on each, surface pK(1/2) values could be determined. In several "mixed" tip/sample combinations, a peak appeared in the titration curve midway between the surface pK(1/2) values of the tip and sample, consistent with an ionic H-bonding model for the interactions. The amine/sulfonic acid pair showed more complex behavior; the amine-terminated tip/sulfonic acid-terminated PDMS surface force titration curve consisted of two peaks centered at pH 4 and pH 8. Reversing the tip/sample pair resulted in the peak positions being shifted upward by 1.0 pH unit. The peak appearing at lower pH is assigned to electrostatic interactions between the two oppositely charged surfaces, whereas the higher pH peak is believed to arise due to ionic H-bonding interactions. AFM images show the effects on surface patterning of amine- and sulfonic acid-modified PDMS surfaces that have undergone two different oxidation methods (air plasma oxidation and Tesla coil oxidation). The surface morphologies of freshly prepared and 24 h aged air plasma oxidized PDMS are also discussed in this study.

Journal Article↗