- N-Leucinyl Benzenesulfonamides as Structurally Simplified Leucyl-tRNA Synthetase Inhibitors
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N-Leucinyl benzenesulfonamides have been discovered as a novel class of potent inhibitors of E. coli leucyl-tRNA synthetase. The binding of inhibitors to the enzyme was measured by using isothermal titration calorimetry. This provided information on enthalpy and entropy contributions to binding, which, together with docking studies, were used for structure-activity relationship analysis. Enzymatic assays revealed that N-leucinyl benzenesulfonamides display remarkable selectivity for E. coli leucyl-tRNA synthetase compared to S. aureus and human orthologues. The simplest analogue of the series, N-leucinyl benzenesulfonamide (R = H), showed the highest affinity against E. coli leucyl-tRNA synthetase and also exhibited antibacterial activity against Gram-negative pathogens (the best MIC = 8 μg/mL, E. coli ATCC 25922), which renders it as a promising template for antibacterial drug discovery.
- Charlton, Michael H.,Aleksis, Rihards,Saint-Leger, Adéla?de,Gupta, Arya,Loza, Einars,Ribas De Pouplana, Lluís,Kaula, Ilze,Gustina, Daina,Madre, Marina,Lola, Daina,Jaudzems, Kristaps,Edmund, Grace,Randall, Christopher P.,Kime, Louise,O'Neill, Alex J.,Goessens, Wil,Jirgensons, Aigars,Finn, Paul W.
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- Amides and Sulfonamides: Efficient Molecular Padlocks for the Template Synthesis of Azacyclam (1,3,5,8,12-Pentaazacyclotetradecane) Macrocycles
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Amides and sulfonamides, both aliphatic and aromatic, acted as efficient locking fragments, in the presence of formaldehyde and base (triethylamine), in closing the open-chain tetramine 1,9-diamino-3,7-diazanonane around labile metal centres prone to a square type of co-ordination, i.e.NiII and CuII, to give a pentaazamacrocyclic complex to the azacyclam family.The product of the copper(II) template reaction involving methanesulfonamide as a locking fragment (3-methanesulfonyl-1,3,5,8,12-pentaazacyclotetradecane)dinitratocopper(II), was obtained in crystalline form and its crystal and molecular structure determined from single-crystal X-ray diffraction data, collected with the use of Cu-Kα radiation: trigonal, space group R3c, a = b = c = 14.997(3) Angstroem, α = β = γ = 98.48(2) deg, Z = 6.Only the four secondary amine nitrogen atoms of the macrocycle are bound to the CuII, giving a regular square stereochemistry.The tertiary nitrogen atom N(1), which presents distinct sp2 structural features, is not involved in the co-ordination.The axial positions of the elongated octahedron are occupied by oxygen atoms of the nitrate ions.A kinetic investigation was carried out on the copper(II) template reactions involving diprotic acids as locking fragments, including amides, amines and carbon acids, such as nitroethane and diethyl malonate: for the systems investigated the rate of the template reaction seems to be related to the strength of the diprotic acid.This suggests that the monodeprotonated form of the acid is present in the rate-determining step of the cyclisation process.
- Blas, Andres De,Santis, Giancarlo De,Fabbrizzi, Luigi,Licchelli, Maurizio,Lanfredi, Anna Maria Manotti,et al.
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- Contribution of Energy Transfer from the Singlet State to the Sensitization of Eu3+and Tb3+Luminescence by Sulfonylamidophosphates
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A series of stable lanthanide complexes Na[Ln(L)4] (Ln=La3+, Eu3+, Gd3+, Tb3+, with L=dimethyl(4-methylphenylsulfonyl)amidophosphate and dimethyl-2-naphthylsulfonylamidophosphate) were synthesized. The compounds were characterized by single-crystal X-ray diffraction, IR, absorption, and emission spectroscopy at 293 and 77 K. In contrast to the usual and well-known dominant role of the ligand triplet state in intramolecular energy transfer processes in Ln complexes, in this particular new class of Ln compounds with sulphonylamidophosphate ligands, strong experimental and detailed theoretical evidence suggest a dominant role is played by the ligand first excited singlet state. The importance of the role played by the7F5level in the case of the Tb3+compound in this process is shown. The theoretical approach for the energy transfer rates was successfully applied to the rationalization of the experimental data. The higher-lying excited levels of Eu (5DJ,5LJ,5GJ) and Tb (5DJ,5GJ,5LJ,5HJ,5FJ,5IJ) were included in the calculations for the first time. Both the multipolar and exchange mechanisms were taken into account. The experimental intensity parameters (Ωλ), emission lifetimes (τ), radiative (Arad) and non-radiative (Anrad) decay rates, and quantum yields (theoretical and experimental) were determined and are discussed in detail.
- Kasprzycka, Ewa,Trush, Victor A.,Amirkhanov, Vladimir M.,Jerzykiewicz, Lucjan,Malta, Oscar L.,Legendziewicz, Janina,Gawryszewska, Paula
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- Chemoselective Cleavage of Acylsulfonamides and Sulfonamides by Aluminum Halides
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The chemoselective cleavage of C-N bonds of amides, sulfonamides, and acylsulfonamides by aluminum halides is described. AlCl3and AlI3display complementary reactivities toward N-alkyl and N-acyl moieties. N-Alkylacylsulfonamides, sec
- Sang, Dayong,Dong, Bingqian,Liu, Yunfeng,Tian, Juan
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p. 3586 - 3595
(2022/02/25)
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- METHOD FOR PRODUCING OXIDE USING BETA-MANGANESE DIOXIDE
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With the object of efficiently producing an oxidation product, the present invention provides a method for producing an oxidation product by oxidizing a raw material compound in the presence of oxygen, wherein the raw material compound is oxidized in the presence of manganese dioxide having a crystal structure of β-type.
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Paragraph 0097; 0098
(2021/10/15)
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- ARYL AND HETEROARYL COMPOUNDS, AND THERAPEUTIC USES THEREOF IN CONDITIONS ASSOCIATED WITH THE ALTERATION OF THE ACTIVITY OF GALACTOCEREBROSIDASE
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The application is directed to compounds of formulae (IA) and (IB): (IA) and (IB), and their salts and solvates, wherein R1a, R2a, A1, A2, A3, A4, R1b, R2b, B1, B2, B3, and G are as set forth in the specification, as well as to methods for their preparation, pharmaceutical compositions comprising the same, and use thereof for the treatment and/or prevention of, e.g., lysosomal storage diseases, such as Krabbe's disease, and α-synucleinopathies, such as Parkinson's disease.
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Page/Page column 120; 121
(2021/06/04)
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- Synthesis, biological evaluation, and docking studies of novel pyrrolo[2,3-b]pyridine derivatives as both ectonucleotide pyrophosphatase/phosphodiesterase inhibitors and antiproliferative agents
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Ecto-nucleotide pyrophosphatases/phosphodiesterases (NPPs) together with nucleoside triphosphate diphosphohydrolases (NTPDases) and alkaline phosphatases (APs) are nucleotidases located at the surface of the cells. NPP1 and NPP3 are important members of NPP family that are known as druggable targets for a number of disorders such as impaired calcification, type 2 diabetes, and cancer. Sulfonylurea derivatives have been reported as antidiabetic and anticancer agents, therefore, we synthesized and investigated series of sulfonylurea derivatives 1a-m possessing pyrrolo[2,3-b]pyridine core as inhibitors of NPP1 and NPP3 isozymes that are over-expressed in cancer and diabetes. The enzymatic evaluation highlighted compound 1a as selective NPP1 inhibitor, however, 1c was observed as the most potent inhibitor of NPP1 with an IC50 value of 0.80 ± 0.04 μM. Compound 1l was found to be the most potent and moderately selective inhibitor of NPP3 (IC50 = 0.55 ± 0.01 μM). Furthermore, in vitro cytotoxicity assays of compounds 1a-m against MCF-7 and HT-29 cancer cell lines exhibited compound 1c (IC50 = 4.70 ± 0.67 μM), and 1h (IC50 = 1.58 ± 0.20 μM) as the most cytotoxic compounds against MCF-7 and HT-29 cancer cell lines, respectively. Both of the investigated compounds showed high degree of selectivity towards cancer cells than normal cells (WI-38). Molecular docking studies of selective and potent enzyme inhibitors revealed promising mode of interactions with important binding sites residues of both isozymes i.e., Thr256, His380, Lys255, Asn277 residues of NPP1 and His329, Thr205, and Leu239 residues of NPP3. In addition, the most potent antiproliferative agent, compound 1h, doesn't produce hypoglycemia as a side effect when injected to mice. This is an additional merit of the promising compound 1h.
- Ullah, Saif,El-Gamal, Mohammed I.,El-Gamal, Randa,Pelletier, Julie,Sévigny, Jean,Shehata, Mahmoud K.,Anbar, Hanan S.,Iqbal, Jamshed
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- Development of succinimide-based inhibitors for the mitochondrial rhomboid protease PARL
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While the biochemistry of rhomboid proteases has been extensively studied since their discovery two decades ago, efforts to define the physiological roles of these enzymes are ongoing and would benefit from chemical probes that can be used to manipulate the functions of these proteins in their native settings. Here, we describe the use of activity-based protein profiling (ABPP) technology to conduct a targeted screen for small-molecule inhibitors of the mitochondrial rhomboid protease PARL, which plays a critical role in regulating mitophagy and cell death. We synthesized a series of succinimide-containing sulfonyl esters and sulfonamides and discovered that these compounds serve as inhibitors of PARL with the most potent sulfonamides having submicromolar affinity for the enzyme. A counterscreen against the bacterial rhomboid protease GlpG demonstrates that several of these compounds display selectivity for PARL over GlpG by as much as two orders of magnitude. Both the sulfonyl ester and sulfonamide scaffolds exhibit reversible binding and are able to engage PARL in mammalian cells. Collectively, our findings provide encouraging precedent for the development of PARL-selective inhibitors and establish N-[(arylsulfonyl)oxy]succinimides and N-arylsulfonylsuccinimides as new molecular scaffolds for inhibiting members of the rhomboid protease family.
- Andrews, Charlotte L.,Cardozo, Joaquin M.,Chow, Alyssa S.,Crainic, Jennifer A.,Parsons, William H.,Rutland, Nicholas T.,Sheehan, Brendan K.
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supporting information
(2021/08/04)
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- One-pot aerobic oxidative sulfonamidation of aromatic thiols with ammonia by a dual-functional β-MnO2 nanocatalyst
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High-surface-area β-MnO2 (β-MnO2-HS) nanoparticles could act as effective heterogeneous catalysts for the one-pot oxidative sulfonamidation of various aromatic and heteroaromatic thiols to the corresponding sulfonamides using molecular oxygen (O2) and ammonia (NH3) as respective oxygen and nitrogen sources, without the need for any additives.
- Hayashi, Eri,Yamaguchi, Yui,Kita, Yusuke,Kamata, Keigo,Hara, Michikazu
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supporting information
p. 2095 - 2098
(2020/02/26)
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- Rationally Designed Polypharmacology: α-Helix Mimetics as Dual Inhibitors of the Oncoproteins Mcl-1 and HDM2
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Protein–protein interactions (PPIs), many of which are dominated by α-helical recognition domains, play key roles in many essential cellular processes, and the dysregulation of these interactions can cause detrimental effects. For instance, aberrant PPIs involving the Bcl-2 protein family can lead to several diseases including cancer, neurodegenerative diseases, and diabetes. Interactions between Bcl-2 pro-life proteins, such as Mcl-1, and pro-death proteins, such as Bim, regulate the intrinsic pathway of apoptosis. p53, a tumor-suppressor protein, also has a pivotal role in apoptosis and is negatively regulated by its E3 ubiquitin ligase HDM2. Both Mcl-1 and HDM2 are upregulated in numerous cancers, and, interestingly, there is crosstalk between both protein pathways. Recently, synergy has been observed between Mcl-1 and HDM2 inhibitors. Towards the development of new anticancer drugs, we herein describe a polypharmacology approach for the dual inhibition of Mcl-1 and HDM2 by employing three densely functionalized isoxazoles, pyrazoles, and thiazoles as mimetics of key α-helical domains of their partner proteins.
- Conlon, Ivie L.,Drennen, Brandon,Lanning, Maryanna E.,Hughes, Samuel,Rothhaas, Rebecca,Wilder, Paul T.,MacKerell, Alexander D.,Fletcher, Steven
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supporting information
p. 1691 - 1698
(2020/07/04)
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- Bone-seeking matrix metalloproteinase inhibitors for the treatment of skeletal malignancy
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Matrix metalloproteinases (MMPs) are a family of enzymes involved at different stages of cancer progression and metastasis. We previously identified a novel class of bisphosphonic inhibitors, selective for MMPs crucial for bone remodeling, such as MMP-2. Due to the increasing relevance of specific MMPs at various stages of tumor malignancy, we focused on improving potency towards certain isoforms. Here, we tackled MMP-9 because of its confirmed role in tumor invasion, metastasis, angiogenesis, and immuno-response, making it an ideal target for cancer therapy. Using a computational analysis, we designed and characterized potent MMP-2/MMP-9 inhibitors. This is a promising approach to develop and clinically translate inhibitors that could be used in combination with standard care therapy for the treatment of skeletal malignancies.
- Laghezza, Antonio,Piemontese, Luca,Brunetti, Leonardo,Caradonna, Alessia,Agamennone, Mariangela,Di Pizio, Antonella,Pochetti, Giorgio,Montanari, Roberta,Capelli, Davide,Tauro, Marilena,Loiodice, Fulvio,Tortorella, Paolo
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- Discovery of novel DAPY-IAS hybrid derivatives as potential HIV-1 inhibitors using molecular hybridization based on crystallographic overlays
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Crystallographic overlap studies and pharmacophoric analysis indicated that diarylpyrimidine (DAPY)-based HIV-1 NNRTIs showed a similar binding mode and pharmacophoric features as indolylarylsulfones (IASs), another class of potent NNRTIs. Thus, a novel series of DAPY-IAS hybrid derivatives were identified as newer NNRTIs using structure-based molecular hybridization. Some target compounds exhibited moderate activities against HIV-1 IIIB strain, among which the two most potent inhibitors possessed EC50 values of 1.48?μM and 1.61?μM, respectively. They were much potent than the reference drug ddI (EC50?=?76.0?μM) and comparable to 3TC (EC50?=?2.54?μM). Compound 7a also exhibited the favorable selectivity index (SI?=?80). Preliminary structure-activity relationships (SARs), structure-cytotoxicity relationships, molecular modeling studies, and in silico calculation of physicochemical properties of these new inhibitors were also discussed.
- Huang, Boshi,Wang, Xueshun,Liu, Xinhao,Chen, Zihui,Li, Wanzhuo,Sun, Songkai,Liu, Huiqing,Daelemans, Dirk,De Clercq, Erik,Pannecouque, Christophe,Zhan, Peng,Liu, Xinyong
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p. 4397 - 4406
(2017/07/22)
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- A general iodine-mediated synthesis of primary sulfonamides from thiols and aqueous ammonia
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A general and efficient methodology for preparing primary sulfonamides has been developed. In the presence of iodine as the catalyst and TBHP (70% in water) as the oxidant, a wide range of primary sulfonamides were prepared from the corresponding thiols and aqueous ammonia in moderate to good yields.
- Feng, Jian-Bo,Wu, Xiao-Feng
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supporting information
p. 6951 - 6954
(2016/07/30)
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- Sulfonamide formation from sodium sulfinates and amines or ammonia under metal-free conditions at ambient temperature
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A novel, practical and highly efficient method for the construction of a variety of sulfonamides mediated by I2 was demonstrated. The reaction proceeds readily at room temperature using a variety of sodium sulfinates and amines or ammonia in water in a metal-, base-, ligand-, or additive-free protocol. Primary, secondary and tertiary sulfonamides were obtained in good to excellent yields with a broad range of functional group tolerability. This journal is
- Yang, Kai,Ke, Miaolin,Lin, Yuanguang,Song, Qiuling
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p. 1395 - 1399
(2015/03/18)
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- SUBSTITUTED BENZOFURAN, BENZOTHIOPHENE AND INDOLE MCL-1 INHIBITORS
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The present invention provides for compounds that inhibit the activity of an anti-apoptotic Bcl-2 family member Myeloid cell leukemia-1 (Mcl-1) protein. The present invention also provides for pharmaceutical compositions as well as methods for using compounds for treatment of diseases and conditions (e.g., cancer) characterized by the over-expression or dysregulation of Mcl-1 protein.
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Page/Page column 250
(2014/04/04)
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- Gadolinium(III) complexes of dota-derived N-sulfonylacetamides (H 4(dota-NHSO2R) = 10-{2-[(R)sulfonylamino]-2-oxoethyl}-1,4, 7,10-tetraazacyclododecane-1,4,7-triacetic acid): A new class of relaxation agents for magnetic resonance imaging applications
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Four new ligands for lanthanide ions based on the H3do3a (= 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) structure and bearing one N-sulfonylacetamide arm were synthesized, i.e., H4dota-NHSO 2R = 10-{2-[(R)sulfonylamino]-2-oxoethyl}-1,4,7,10- tetraazacyclododecane-1,4,7-triacetic acids 1a-e. A 15N-NMR study of the 15N-labelled Eu3+ complex of one such ligands, 1d, showed that the coordination of the N-sulfonylacetamide arm involves the carbonyl O-atom rather than the N-atom. The relaxometric properties of the corresponding Gd3+ complexes were investigated as a function of pH and temperature. These complexes have relaxivities in the range 4.5-5.3 mM -1 s-1, at 20 MHz and 25°, and are characterized by a single H2O molecule in their inner coordination sphere. The mean residence lifetime of this molecule is relatively long (500-700 ns) compared to other anionic complexes. The slow rate of H2O exchange can be justified by the extensive delocalization of the negative charge on the N-sulfonylacetamide arm. The long residence time of the coordinated H 2O allowed the observation of the effect of the prototropic exchange on the relaxivity. The study of the interaction between the complex [Gd(1e)]- and HSA revealed a weak affinity constant highlighting the importance of a localized negative charge on the complex to promote a strong interaction with the protein.
- Aime, Silvio,Botta, Mauro,Cravotto, Giancarlo,Frullano, Luca,Giovenzana, Giovanni B.,Crich, Simonetta Geninatti,Palmisano, Giovanni,Sisti, Massimo
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p. 588 - 603
(2007/10/03)
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- Unprecedented observation of sulfonamides in the transesterification of N-unsubstituted carbamates with sulfonyl chlorides
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Sulfonamides have been identified as by-products in the base-mediated transesterification of N-unsubstituted carbamates with sulfonyl chlorides to give the corresponding sulfonates. A proposed mechanism and the synthesis of hindered 2,6-disubstituted arylsulfonates via this method are also reported.
- Dauvergne, Jér?me,Wellington, Kevin,Chibale, Kelly
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- Homochiral 4-azalysine building blocks: Syntheses and applications in solid-phase chemistry
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Anomalous amino acids not only play central roles as mimics of natural amino acids but also offer opportunities as unique building blocks for combinatorial chemistry. This paper describes the chiral syntheses and solid-phase applications of a versatile atypical amino acid, 4-azalysine (2,6-diamino-4-azahexanoic acid) 1. The syntheses of differentially protected 4-azalysine derivatives 28a-e have been developed by two efficient and inexpensive routes that start either from Garner's aldehyde 16 or the chiron (S)-Nα-Cbz-2,3-diaminopropionic acid 23. Both approaches employ the convergent modular concept and exploit reductive amination of aldehydes with amines as the key step for the fusion of the two segments. In the first route, the overall process inverts the chirality of the starting material, L-serine, and thus provides an excellent route to the unnatural D-isomers. The alternative route starting from L-asparagine provides a shorter and high-yielding route to orthogonally protected 4-azalysine derivatives. The corresponding N2-Fmoc-4-azalysines 31a-e, readily derived from the key intermediate 27, are compatible with the Fmoc-based solid-phase peptide synthesis (SPPS) and solid-phase organic chemistry (SPOC) protocols. Furthermore, the utility and versatility of another key structure, tris-Boc-4-azalysine 2 in the engineering of novel high-loading dendrimeric polystyrene resins 33 and 36, have been demonstrated. Following derivatization with the Rink amide linker 34, the stability and robustness of these resin-bound dendrimers 35 and 37 in the synthesis of small molecules using a range of reaction conditions (e.g., Mitsunobu and Suzuki reactions) have been effectively illustrated.
- Chhabra, Siri Ram,Mahajan, Anju,Chan, Weng C.
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p. 4017 - 4029
(2007/10/03)
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- Resin-bound dendrimers as high loading supports for solid phase chemistry
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The synthesis of a tris-Boc tri-amino acid and its utility in the generation of dendrimers as inert scaffolds on solid supports is described. These high loading amine functionalized resins were successfully used in the synthesis of small molecules.
- Mahajan, Anju,Chhabra, Siri Ram,Chan, Weng C.
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p. 4909 - 4912
(2007/10/03)
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- Modified borohydride agents, bis(triphenylphosphine) (tetra-hydroborato)zinc complex [Zn(BH4)2(PPh3)2] and (triphenylphosphine) (tetrahydroborato)zinc complex [Zn(BH4)2(PPh3)]. New ligand metal borohydrides as stable, efficient, and versatile reducing agents
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Bis(triphenylphosphine)(tetrahydroborato)zinc and (triphenylphosphine)(tetrahydroborato) zinc complexes have been used for the efficient reductions of varieties of organic compounds in THF or under solvent free conditions. Selective reduction of aldehydes, ketones, α,β-unsaturated carbonyl compounds, and acyl chlorides to their corresponding alcohols and aryl, alkyl, aroyl, and sulfonyl azides to their corresponding amines and amides are described. Bis(triphenylphosphine)(tetrahydroboratro)zinc complex shows promising shelf stability and is much more stable than its mono triphenylphosphine analogue. The reducing ability of the two complexes is more or less the same.
- Firouzabadi, Habib,Adibi, Mina,Ghadami, Mahboobeh
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p. 191 - 220
(2007/10/03)
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- Reduction of Azides with Zinc Borohydride
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Zinc borohydride in 1,2-dimethoxyethane provides an efficient procedure for the reduction of organic azides.Aroyl, acyl, and arylsulfonyl azides readily undergo reduction at room temperatue to produce amides and sulfonamides in excellent yields; however, substitution with electron-withdrawing groups in the aroyl azides leads to the corresponding benzyl alcohols.Reduction of aryl and alkyl azides has also been achieved in high yields, under some modified conditions.
- Ranu, Brindaban C.,Sarkar, Arunkanti,Chakraborty, Rupak
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p. 4114 - 4116
(2007/10/02)
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- Unconventional Regiospecific Syntheses of Aromatic Carbonamides and Thiocarbonamides by Means of Tin-Mediated Friedel-Crafts Reactions
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Friedel-Crafts reactions of stannylarenes 1 with tosyl isocyanate (TsNCO, 2) give N-tosylcarbonamides 3 via ipso substitution of the stannyl group.Thus, unconventionally substituted aromatic carbonamides can be obtained.The combination of the reaction of 1 and 2 with that of 1 and chlorosulfonyl isocyanate (14) allows one-pot syntheses of N-(arylsulfonyl)-substituted aromatic carbonamides with optional substitution patterns on both aromatic rings.The known ipso-specific substitutions of stannylarenes with 14 are extended to bi- and tricyclic arenes as well as to thiophenes 6 and 22.One stannyl group can serve as a leaving group for two aromatic systems, as shown with diaryldialkyltins 29.Also, stannylalkanes such as 27 react with 14 to afford alkylsulfonyl isocyanates and products of further reactions, such as 28.From the reactions of 1 with ethoxycarbonyl isocyanate (32), ortho- and meta-substituted aromatic thiocarbonamides 33 which are potential precursors for further syntheses, are accessible.The scope, limitations, and mechanism of these electrophilic substitutions are outlined.
- Arnswald, Martin,Neumann, Wilhelm P.
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p. 7022 - 7028
(2007/10/02)
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- The Electrostatically Paired Bis(dimethyl sulfoxide)(tetrakis(1-methylpyridinium-4-yl)porphinato)iron(III)/(4,4',4'',4'''-Tetrasulfonatophthalocyaninato)zinc(II) System. Solution Structure and Dynamics
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The electrostatic pairing interactions between the bis(dimethyl sulfoxide)(tetrakis(1-methylpyridinium-4-yl)porphinato)iron(III) cation, 5+, and the (4,4',4'',4'''-tetrasulfonatophthalocyaninato)zinc(II) anion, 4-, have been studied in dimethyl sulfoxide (DMSO) solution.Measurements of the electrostatic pair association constant, Kep, and its dependence upon ionic strength (Me4NClO4) were made with standard visible spectroscopic techniques while association dynamics were studied by NMR methods in DMSO-d6 solution.The exchange rate lawfor electrostatic pair formation takes into account DMSO solvent exchange of the iron porphyrin-solvent complex, and the exchange lifetime for the pair at ionic strength of 1 mM is calculated to be ca. 0.24 s at 25 deg C.Solution structural assessments were made by using measurements of the intermolecular dipolar relaxation of the (tetrasulfonatophthalocyaninato)zinc(II) protons due to the paramagnetic high-spin iron(III) center in the electrostatic pair.The structural model developed permitted calculation of a set of possible iron positions with respect to the phthalocyanine plane which are consistent with a cofacial dimeric structure displaying ?-? interactions due to pyrrole ring overlap.
- Goodwin, John A.,Scheidt, W. Robert
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p. 4432 - 4439
(2007/10/02)
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- Oxidation of thiols and disulfides to sulfonic acids
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A process for formation of a sulfonic acid through oxidation of a thiol or disulfide. The process is carried out in the presence of a sulfoxide such as dimethyl sulfoxide, a halogen or hydrogen halide catalyst, and an excess quantity of water. The water acts as a moderator for the oxidation reaction to reduce the level of decomposition of the sulfoxide and, thereby, to improve the overall efficiency of the process. An intermolecular compound of an amino acid containing a sulfonic acid group and a carboxylic acid group with a sulfoxide in which the amino acid is at least moderately soluble. A method which comprises reacting an amino acid containing a sulfonic acid group and a carboxylic acid group with a sulfoxide in which the amino acid is at least moderately soluble. A method for recovering an amino acid containing a sulfonic acid group and a carboxylic acid group from an admixture of the amino acid with other ingredients by adding thereto a sulfoxide in which the amino acid is moderately soluble, with the sulfoxide being added in a sufficient amount to solubilize the amino acid, separating an intermolecular compound of the amino acid with the sulfoxide, and then recovering the amino acid from its intermolecular compound.
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