Tosyl Moiety Research Articles

Synthesis, Characterization and Interconversion of p-Tolylsulfone-Functionalized Norbornadiene/Quadricyclane Couples.

We report the synthesis and characterization of library of new 2,3-disubstituted norbornadiene/quadricyclane couples. For the first time, the para-tolylsulfone moiety was employed as electron-withdrawing substituent in combination with a variety of different electron donors as counterparts. Comprehensive characterization was conducted for every interconversion couple. By comparison with structurally related molecules published before we established the tosyl moiety as suitable alternative to previously investigated ester functionalities by providing similar photophysical properties. The photo-induced interconversion behavior was investigated via UV/Vis- and NMR-spectroscopy. The UV/Vis experiments were carried out exclusively in acetonitrile, whereas several solvents were investigated in the NMR studies. A detailed description and comparison of the isomerization behavior is provided, while examining relevant optical properties like λmax and λonset. Thereby, an enhanced red-shift up to λmax=394 nm combined with an λonset value of 469 nm could be generated which is necessary for potential applications.

Synthesis, Characterization, and Docking Study of a Novel Indole Derivative Containing a Tosyl Moiety as Anti-Oxidant Agent

Synthesis, Characterization, and Docking Study of a Novel Indole Derivative Containing a Tosyl Moiety as Anti-Oxidant Agent

Synthesis and characterization of amino-functionalized guar gum based polyurea: Preparation of iodine complexes, structural investigation and release studies

Biobased materials are expanding dramatically in various industrial applications due to their unique intrinsic properties. In this study, various chemical functionalization procedures were used to synthesize guar gum, a naturally occurring polysaccharide-based polyurea, and its iodine complexes. Firstly, guar gum was subjected to tosylation reaction using p-toluene sulphonyl chloride to introduce tosyl moieties in the polymer chain with the degree of substitution (DS) ranging between 0.16 and 1.54. Sample having the highest degree of tosyl moiety was further reacted with tris(2-aminoethyl) amine to produce 6-deoxy-6-tris(2-aminoethyl) amine derivative via nucleophilic substitution reaction to impart amino functional groups. The degree of substitution in 6-deoxy-6-tris(2-aminoethyl) amine derivative was found to be 0.59. 6-deoxy-6-tris(2-aminoethyl) amine derivative was reacted with different diisocyanates (Toluene-2,4-diisocyanate (TDI), 1,6-diisocyanatohexane (HMDI)) to produce guar gum based polyurea. Iodine complexes of the resulting polyurea were prepared by reacting with different iodinating agents. Different chemical reactions, formation of polyurea and its iodine complexes were thoroughly analyzed by different analytical techniques such as FT-IR, NMR, elemental analysis, XRD, UV–Vis spectroscopy, and a reaction scheme has been proposed. Morphological and rheological characteristics were analyzed by SEM and viscosity measurement. Thermal analysis was carried out by TGA and DSC studies. Finally, by examining the complex's UV–Vis spectra, the iodine release characteristics from polyurea‑iodine complexes were investigated.

Synthesis of Aminoethyl-Substituted Piperidine Derivatives as σ1 Receptor Ligands with Antiproliferative Properties.

A series of novel σ1 receptor ligands with a 4‐(2‐aminoethyl)piperidine scaffold was prepared and biologically evaluated. The underlying concept of our project was the improvement of the lipophilic ligand efficiency of previously synthesized potent σ1 ligands. The key steps of the synthesis comprise the conjugate addition of phenylboronic acid at dihydropyridin‐4(1H)‐ones 7, homologation of the ketones 8 and introduction of diverse amino moieties and piperidine N‐substituents. 1‐Methylpiperidines showed particular high σ1 receptor affinity and selectivity over the σ2 subtype, whilst piperidines with a proton, a tosyl moiety or an ethyl moiety exhibited considerably lower σ1 affinity. Molecular dynamics simulations with per‐residue binding free energy deconvolution demonstrated that different interactions of the basic piperidine‐N‐atom and its substituents (or the cyclohexane ring) with the lipophilic binding pocket consisting of Leu105, Thr181, Leu182, Ala185, Leu186, Thr202 and Tyr206 are responsible for the different σ1 receptor affinities. Recorded logD7.4 and calculated clogP values of 4a and 18a indicate low lipophilicity and thus high lipophilic ligand efficiency. Piperidine 4a inhibited the growth of human non‐small cell lung cancer cells A427 to a similar extent as the σ1 antagonist haloperidol. 1‐Methylpiperidines 20a, 21a and 22a showed stronger antiproliferative effects on androgen negative human prostate cancer cells DU145 than the σ1 ligands NE100 and S1RA.

Synthesis of aminocyanopyrazoles via a multi-component reaction and anti-carbonic anhydrase inhibitory activity of their sulfamide derivatives against cytosolic and transmembrane isoforms

A convenient protocol for the multicomponent reaction (MCRs) between malononitrile with an orthoester and hydrazine derivatives, under acid catalyst is described. A series of aminocyanopyrazoles 4 was prepared, isolated and characterized. These pyrazoles reacted with sodium nitrite followed by secondary amine reagent and with formic acid to lead pyrazolotriazines 6 and pyrazolopyrimidinones 7. Some of the aminopyrazoles were converted to the corresponding sulfamides by reaction with sulfamoyl chloride. The aminopyrazoles incorporating phenyl and tosyl moieties were tested as inhibitors of four carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the human (h) hCA I, II, IX and XII. Many of them showed low micromolar or submicromolar inhibition of these enzymes. The corresponding sulfamides were low nanomolar CA inhibitors.

Secondary/tertiary benzenesulfonamides with inhibitory action against the cytosolic human carbonic anhydrase isoforms I and II

Carbonic anhydrase inhibitors of primary sulfonamide type, RSO2NH2, have clinical applications as diuretics, antiglaucoma, antiepileptic, antiobesity and antitumor drugs. Here we investigated inhibition of two human cytosolic isozymes, hCA I and II, with a series of secondary/tertiary sulfonamides, incorporating tosyl moieties (CH3C6H4SO2NR1R2). Most compounds inhibited both isoforms in low micromolar range, with inhibition constants between 0.181–6.01 μM against hCA I, and 0.209–0.779 μM against hCA II, respectively. These findings point out that substituted benzenesulfonamides may be used as leads for generating interesting CAIs probably possessing a distinct mechanism of action compared to primary sulfonamides. Indeed, classical RSO2NH2 inhibitors bind in deprotonated form to the Zn(II) ion from the CA active site and participate in many other favorable interactions with amino acid residues lining the cavity. The secondary/tertiary sulfonamides cannot bind to the zinc due to steric hindrance and probably are accommodated at the entrance of the active site, in coumarin binding-site.

2,6-Bis(tosyl-oxymeth-yl)pyridine.

The title compound, C21H21NO6S2, is organized around a twofold axis parallel to the crystallographic c axis and containing the N atom and a C atom of the pyridine ring. The tosyl moiety and the pyridine ring are both essentially planar [maximum deviations 0.028 (2) and 0.020 (3) Å, respectively]; their mean planes form a dihedral angle of 33.0 (2)°.

ChemInform Abstract: An Investigation of Imidazole and Oxazole Syntheses Using Aryl-Substituted TosMIC Reagents.

This article describes efficient and mild protocols for preparing polysubstituted imidazoles in a single pot from aryl-substituted tosylmethyl isocyanide (TosMIC) reagents and imines generated in situ. Traditional imine-forming reactions employing virtually any aldehyde and amine followed by addition of the TosMIC reagent delivers 1,4,5-trisubstituted imidazoles with predictable regiochemistry. Employing chiral amines and aldehydes, particularly those derived from α-amino acids, affords imidazoles with asymmetric centers appended to N-1 or C-5 with excellent retention of chiral purity. 1,4-Disubstituted imidazoles are also readily prepared by a simple variant of the above procedure. Selecting glyoxylic acid as the aldehyde component of this procedure leads to intermediates such as 48, which readily undergo decarboxylation and elimination of the tosyl moiety to deliver 1,4-disubstituted imidazoles in high yields. Alternatively, using NH4OH as the amine component in conjunction with a variety of aldehydes d...

ChemInform Abstract: Synthesis of L-3′-Hydroxymethylribonucleosides.

The target compounds were synthesized via the key intermediate carbohydrate 8, which was synthesized by first selectively protecting the 1'- and 2'-hydroxyl groups followed by selective tosylation of the 5'-hydroxyl group to obtain compound 3. The tosyl moiety was then replaced by a benzyl either to obtain 4. Compound 4 underwent Dess-Martin oxidation to afford the ketone 5. Compound 5 was subjected to Wittig olefination to afford the alkene 6 followed by regioselective hydroboration to obtain 7. Compound 7 was fully acetylated using acetic acid, acetic anhydride and sulfuric acid to obtain the key intermediate 8.

2-(1,3-Dioxoisoindolin-2-yl)ethyl 4-methylbenzenesulfonate

In the title mol­ecule, C17H15NO5S, the dihedral angle between the essentially planar atoms of the tosyl moiety (the S atom and the seven tolyl C atoms) and the phthalimide moiety is 6.089 (3)°. The mol­ecule is folded about the ethyl­ene bridge, adopting a staggered conformation such that the benzene ring of the tosyl group and the five-membered ring of the phthalimide moiety have a face-to-face orientation with a centroid-to-centroid separation of 3.7454 (12) Å. The crystal structure is stabilized by weak inter­molecular π–π inter­actions between symmetry-related five-membered rings of the phthalimide groups, with a centroid-to-centroid distance of 3.3867 (11) Å. The compound is used for the attachment of a suitable chelate functionality for radiolabeling purposes.

Noncovalent polymers based on aromatic derivatives of β-cyclodextrin

6-Monotosyl-and 6-mononaphthyl derivatives of β-cyclodextrin have been synthesized, and their self-association abilities have been compared. The quasi-elastic light-scattering study revealed the occurrence of self-organization of mono-6-naphtyl-β-cyclodextrin in dilute aqueous solutions that is responsible for the formation of nanosized aggregates. It is suggested that the driving forces of self-organization are the combination of hydrophobic interactions between the aromatic group of one cyclodextrin molecule and the cavity of the neighboring macrocycle that lead to the formation of noncovalent polymers and hydrogen bonds between these polymers. The absence of intermolecular interactions in the case of mono-6-tosyl-β-cyclodextrin is apparently related to the discrepancy between sizes of the tosyl moiety and of the β-cyclodextrin cavity. The influence of concentration, temperature, pH of solution, and competing low-molecular-mass agents on the self-assembly and stability of supramolecular polymers has been studied.

Characterization of poly[(R)‐3‐hydroxybutyrate‐co‐ε‐caprolactone] copolymers by matrix‐assisted laser desorption/ionization time‐of‐flight and electrospray ionization mass spectrometry

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of narrowly dispersed molecular weight gel permeation chromatography (GPC) fractions was used to characterize random and microblock poly[(R)-3-hydroxybutyrate-co-epsilon-caprolactone] [P(HB-co-CL)] copolymers obtained via the acid-catalyzed transesterification of the corresponding homopolymers, poly([(R)-3-hydroxybutyrate] (PHB) and poly(epsilon-caprolactone) (PCL). High-quality mass spectra were obtained, which made it possible to establish the nature of the polymer end groups. Besides the carboxylic termination, two other moieties were found: alcoholic and tosyl end groups. MALDI mass spectra of CL-rich samples possessed mostly tosyl end groups, while HB-rich samples possessed mostly alcoholic end groups, showing that the tosyl moiety is linked prevalently to CL terminal units. The higher resolution of electrospray ionization (ESI) mass spectra of lower molecular weight GPC fractions permitted the identification of the different oligomer species hypothesized in the assignment of the corresponding MALDI mass spectra. Partial methanolysis of these copolymers was explored as a method of producing mixed HB-CL oligomers to be utilized as new synthons, possessing a minor number of chiral centers from those obtained from hydrolysis of biotechnologically synthesized poly(hydroxyalkanoates) (PHAs).

Synthesis, characterization and properties of methylaminocellulose

Homogeneously prepared tosylcelluloses (TC) with degrees of substitution (DS) of DSTos 0.1–1.8 were used as intermediates for the synthesis of methylaminocelluloses (MAC) by nucleophilic substitution with methylamine. TC with DSTos up to 1.1 were shown to be valuable intermediates for selective synthesis of MAC with DSMA varying from 0.1 to approximately 1. No nucleophilic substitution was observed at higher DSTos. At the chosen reaction conditions (60 °C, 48 h) residual tosyl moieties remained unchanged and little hydrolysis took place. The samples obtained were characterized by means of elemental analysis, FTIR and 13C CP/MAS NMR spectroscopy. 13C CP/MAS NMR spectroscopy was found to be an efficient tool for quantification of DSMA. Furthermore, the swelling behaviour in water was investigated and preliminary tests concerning the bilirubin adsorption capacity of MAC were carried out.

Guest-responsive fluorescence variations of gamma-cyclodextrins labeled with hetero-functionalized pyrene and tosyl moieties.

Regioselectively hetero-labeled hosts, 6A-pyrenebutylate-6X-tosyl-modified gamma-cyclodextrins (X = B or H, C or G, D or F, and E for gamma-1, gamma-2, gamma-3, and gamma-4, respectively), were synthesized in order to investigate their chemo-sensor properties for applications to organic compounds, such as bile acids and terpenes. The hosts (gamma-1, gamma-2, gamma-3, and gamma-4) exhibit pure monomer fluorescence. The guest-induced fluorescence emissions of these hosts were suppressed in the presence of guests. The extent of fluorescence variations of these hosts with guests was recognized as a manifestation of the sensing ability of the hosts. A sensing parameter (deltaI/I0, where I and I0 are the fluorescence intensities in the presence and absence of a guest and deltaI = I0-I) was used to describe the sensing ability of these hosts. Host gamma-analogs were able to detect progesterone, ursodeoxycholic acid, chenodeoxycholic acid, and (-)-borneol with high sensitivity. The behaviors of the appended moieties of these hosts during the formation of host-guest complexes were studied using induced circular dichroism (ICD) spectra, fluorescence spectra and the MM2-energy-minimized structure. The host gamma-analogs exhibited different ICD spectra patterns before and after the addition of ursodeoxycholic acid. The guest-induced variations of ICD and the fluorescence spectra and MM2-minimized structures suggest that the pyrene and tosyl moieties move by altering the spatial relationship between them, in which the pyrene moiety works as a hydrophobic cap and the tosyl moiety is speculated to act as a spacer.

Synthesis of a Selective Fluorescent Sensing System Based on γ -Cyclodextrin Modified with Pyrene and Tosyl on the Hetero Rims

The hetero-functionalized host bearing pyrene andtosyl moieties substituted at the lower and upper rims of cyclodextrin, namely,mono-3A-deoxy-3A-pyrenebutylamido-6X-O-mono-(p-toluenesulfonyl)mono-altro-γ-cyclodextrin(mixture :gamma; -1; X = A, B, C, D, E, F, G,or H), has been synthesized in order to investigate itsfluorescent sensing system for organic guests such as steroidsand terpenoids. This host showed pure monomer fluorescence, in which the host fluorescence increasedin intensity on accommodation of bile acids and terpenoids or decreased in fluorescence intensityupon addition of ketosteroids. The extent of fluorescence variation with a guest was employed to evaluatethe sensing ability of the host. The sensing parameter Δ I/I°, where I and I°are the fluorescence intensities in the presence and absence of a guest and Δ I is I - I°, was used to describe the sensing ability. The host detected ketosteroids with negative parameters, on theother hand, bile acids and terpenoids were recognized by the host with positive parameters. Thebehaviors of the appended moieties of the host during host–guest complexation were studied by induced circulardichroism (ICD) and fluorescence spectra. The host compound showed different patterns depending on theguest. The guest-induced variations in the ICD and fluorescent spectra suggest that the pyrene moietyacts to elevate the binding ability and the tosyl moiety plays a roll as a spacer to regulate thecyclodextrin cavity size.

Synthesis and13C CP MAS NMR spectroscopy of cellulose-graft-poly(N-acetylethylenimine)

Starting from homogeneously prepared tosyl celluloses with DS Tos values ranging from 0.2 to 1.8 poly(N-acetylethylenimine) was grafted onto the cellulose backbone. Tosyl moieties served as starting centers for the living ring opening polymerization using 2-methyl-1,3-oxazoline as the monomeric unit. The grafted products could be characterized by IR and 13 C CP MAS NMR spectroscopy clearly indicating the loss of tosyl moieties as well as the occurrence of the N-acetylethylenimine residues. 13 C CP MAS NMR spectroscopy was also found to be an efficient tool for the quantification of grafted polymer after determination of the relaxation behavior of the various nuclei. Thus the grafting efficiency could be controlled by the DS Tos of the starting tosyl celluloses, whereas the amount of monomers showed only a minor influence on the grafting density.

Diastereoselective Synthesis of Ferrocenyl Sulfoximines with Planar and Central Chirality

The capability of the sulfonimidoyl moiety to serve as ortho-directing group for the diastereoselective lithiation of enantiopure ferrocenylsulfoximines is demonstrated. (S)-N-p-Tolylsulfonyl-S-ferrocenyl-S-tert-butylsulfoximine showed excellent diastereoselectivity concerning planar chirality of the products obtained after quenching of the lithium species with several electrophiles. Various electrophiles (MeI, Me2S2, Me3SiCl, p-anisaldehyde, acetone, n-Bu3SnCl, I2) were introduced in yields from 36 to 78%. Only up to 10% of product substituted at both the cyclopentadienyl ring and the phenyl group of the tosyl moiety was isolated as byproduct. The relative configuration of the products was determined by chemical correlation and X-ray crystallographic analysis of (S,Rp)-N-p-tolylsulfonyl-S-tert-butyl-S-(2-iodoferrocenyl)sulfoximine. Taking into account the structure of the starting material, the ortho-directing effect can be ascribed to the oxygen atom of the sulfoximine.

An investigation of imidazole and oxazole syntheses using aryl-substituted TosMIC reagents.

This article describes efficient and mild protocols for preparing polysubstituted imidazoles in a single pot from aryl-substituted tosylmethyl isocyanide (TosMIC) reagents and imines generated in situ. Traditional imine-forming reactions employing virtually any aldehyde and amine followed by addition of the TosMIC reagent delivers 1,4,5-trisubstituted imidazoles with predictable regiochemistry. Employing chiral amines and aldehydes, particularly those derived from alpha-amino acids, affords imidazoles with asymmetric centers appended to N-1 or C-5 with excellent retention of chiral purity. 1,4-Disubstituted imidazoles are also readily prepared by a simple variant of the above procedure. Selecting glyoxylic acid as the aldehyde component of this procedure leads to intermediates such as 48, which readily undergo decarboxylation and elimination of the tosyl moiety to deliver 1,4-disubstituted imidazoles in high yields. Alternatively, using NH(4)OH as the amine component in conjunction with a variety of aldehydes delivers 4, 5-disubstituted imidazoles in moderate to good yields in a single pot while avoiding the need for protecting groups. Finally, the facile preparation of mono- and disubstituted oxazoles from these TosMIC reagents and aldehydes is described.

Synthesis of L-3′-Hydroxymethylribonucleosides

The target compounds were synthesized via the key intermediate carbohydrate 8, which was synthesized by first selectively protecting the 1′ - and 2′- hydroxyl groups followed by selective tosylation of the 5′ -hydroxyl group to obtain compound 3. The tosyl moiety was then replaced by a benzyl ether to obtain 4. Compound 4 underwent Dess-Martin oxidation to afford the ketone 5. Compound 5 was subjected to Wittig olefination to afford the alkene 6 followed by regioselective hydroboration to obtain 7. Compound 7 was fully acetylated using acetic acid, acetic anhydride and sulfuric acid to obtain the key intermediate 8.

Crystal structure of 6,6'-ditosyl-α-α'-trehalose-methanol-water (1/2/2), C52H68O30S4 ∙ 2CH3OH ∙ 2H2O

Article Crystal structure of 6,6'-ditosyl-α-α'-trehalose-methanol-water (1/2/2), C52H68O30S4 ∙ 2CH3OH ∙ 2H2O was published on June 1, 1999 in the journal Zeitschrift für Kristallographie - New Crystal Structures (volume 214, issue 2).