- Alternative Strategy to Obtain Artificial Imine Reductase by Exploiting Vancomycin/D-Ala-D-Ala Interactions with an Iridium Metal Complex
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Based on the supramolecular interaction between vancomycin (Van), an antibiotic glycopeptide, and D-Ala-D-Ala (DADA) dipeptides, a novel class of artificial metalloenzymes was synthesized and characterized. The presence of an iridium(III) ligand at the N-terminus of DADA allowed the use of the metalloenzyme as a catalyst in the asymmetric transfer hydrogenation of cyclic imines. In particular, the type of link between DADA and the metal-chelating moiety was found to be fundamental for inducing asymmetry in the reaction outcome, as highlighted by both computational studies and catalytic results. Using the [IrCp*(m-I)Cl]Cl Van complex in 0.1 M CH3COONa buffer at pH 5, a significant 70% (S) e.e. was obtained in the reduction of quinaldine B.
- Facchetti, Giorgio,Bucci, Raffaella,Fusè, Marco,Erba, Emanuela,Gandolfi, Raffaella,Pellegrino, Sara,Rimoldi, Isabella
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- Aqueous process chemistry: The preparation of aryl sulfonyl chlorides
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The use of aqueous acidic conditions for the preparation of arylsulfonyl chlorides from diazonium salts in the presence of copper salts, preferably CuCl, together with thionyl chloride as the sulfur dioxide source, has considerable advantages over recommended literature procedures, whereby reactions are carried out in acetic acid with minimisation of water content of the solvent. The method has been shown to be successful for a wide range of electron-deficient and electron-neutral aryl substrates. The sulfonyl chlorides are protected from hydrolysis by their low solubility in water, which results in their direct precipitation from the reaction mixture in good yields (>70%) and high strength (>98% w/w). The aqueous process, which is additionally safer and more robust, can be readily scaled up and has significant environmental benefits.
- Hogan, Philip J.,Cox, Brian G.
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Read Online
- Selective Late-Stage Sulfonyl Chloride Formation from Sulfonamides Enabled by Pyry-BF4
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Reported here is a simple and practical functionalization of primary sulfonamides, by means of a pyrylium salt (Pyry-BF4), with nucleophiles. This simple reagent activates the poorly nucleophilic NH2 group in a sulfonamide, enabling the formation of one of the best electrophiles in organic synthesis: a sulfonyl chloride. Because of the variety of primary sulfonamides in pharmaceutical contexts, special attention has been focused on the direct conversion of densely functionalized primary sulfonamides by a late-stage formation of the corresponding sulfonyl chloride. A variety of nucleophiles could be engaged in this transformation, thus permitting the synthesis of complex sulfonamides, sulfonates, sulfides, sulfonyl fluorides, and sulfonic acids. The mild reaction conditions and the high selectivity of Pyry-BF4 towards NH2 groups permit the formation of sulfonyl chlorides in a late-stage fashion, tolerating a preponderance of sensitive functionalities.
- Gómez-Palomino, Alejandro,Cornella, Josep
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supporting information
p. 18235 - 18239
(2019/11/13)
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- A2B Adenosine Receptor Antagonists with Picomolar Potency
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The A2B adenosine receptor (A2BAR) was proposed as a novel target for the (immuno)therapy of cancer since A2BAR blockade results in antiproliferative, antiangiogenic, antimetastatic, and immunostimulatory effects. In this study, we explored the structure-activity relationships of xanthin-8-yl-benzenesulfonamides mainly by introducing a variety of linkers and substituents attached to the sulfonamide residue. A new, convergent strategy was established, which facilitated the synthesis of the target compounds. Many of the new compounds exhibited subnanomolar affinity for the A2BAR combined with high selectivity. Functional groups were introduced, which will allow the attachment of dyes and other reporter groups. 8-(4-((4-(4-Bromophenyl)piperazin-1-yl)sulfonyl)phenyl)-1-propylxanthine (34, PSB-1901) was the most potent A2B-antagonist (Ki 0.0835 nM, KB 0.0598 nM, human A2BAR) with >10 000-fold selectivity versus all other AR subtypes. It was similarly potent and selective at the mouse A2BAR, making it a promising tool for preclinical studies. Computational studies predicted halogen bonding to contribute to the outstanding potency of 34.
- Jiang, Jie,Seel, Catharina Julia,Temirak, Ahmed,Namasivayam, Vigneshwaran,Arridu, Antonella,Schabikowski, Jakub,Baqi, Younis,Hinz, Sonja,Hockemeyer, J?rg,Müller, Christa E.
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supporting information
p. 4032 - 4055
(2019/05/06)
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- Aromatic sulfonyl fluorides covalently kinetically stabilize transthyretin to prevent amyloidogenesis while affording a fluorescent conjugate
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Molecules that bind selectively to a given protein and then undergo a rapid chemoselective reaction to form a covalent conjugate have utility in drug development. Herein a library of 1,3,4-oxadiazoles substituted at the 2 position with an aryl sulfonyl fluoride and at the 5 position with a substituted aryl known to have high affinity for the inner thyroxine binding subsite of transthyretin (TTR) was conceived of by structure-based design principles and was chemically synthesized. When bound in the thyroxine binding site, most of the aryl sulfonyl fluorides react rapidly and chemoselectively with the pK a-perturbed K15 residue, kinetically stabilizing TTR and thus preventing amyloid fibril formation, known to cause polyneuropathy. Conjugation t50s range from 1 to 4 min, ~1400 times faster than the hydrolysis reaction outside the thyroxine binding site. X-ray crystallography confirms the anticipated binding orientation and sheds light on the sulfonyl fluoride activation leading to the sulfonamide linkage to TTR. A few of the aryl sulfonyl fluorides efficiently form conjugates with TTR in plasma. Eleven of the TTR covalent kinetic stabilizers synthesized exhibit fluorescence upon conjugation and therefore could have imaging applications as a consequence of the environment sensitive fluorescence of the chromophore.
- Grimster, Neil P.,Connelly, Stephen,Baranczak, Aleksandra,Dong, Jiajia,Krasnova, Larissa B.,Sharpless, K. Barry,Powers, Evan T.,Wilson, Ian A.,Kelly, Jeffery W.
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supporting information
p. 5656 - 5668
(2013/06/04)
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- Design and synthesis of small molecular dual inhibitor of falcipain-2 and dihydrofolate reductase as antimalarial agent
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Resistance of malaria parasites has quickly developed to almost all used antimalarial drugs. Accordingly, the discovery of new effective drugs to counter the spread of malaria parasites that are resistant to existing agents, especially acting on multi-targets, is an urgent need. The cysteine protease falcipain-2 (FP-2) and dihydrofolate reductase (DHFR) play crucial roles in the Plasmodium life cycle. In this study, a series of first-gereration small molecular dual inhibitor of FP-2 and DHFR have been designed and synthesized based on the lead compound 1, which was randomly identified by screening FP-2 inhibitors in our laboratory. Six compounds (2f-g, 2j, and 2m-o) showed improved dual inhibitory activities against FP-2 (IC50 = 2.7-13.2 μM) and DHFR (IC50 = 1.8-19.8 μM), and the inhibitory capability of compound 2o against FP-2 and DHFR were increased ~8 and ~6 times than that of compound 1, respectively. Moreover, compound 2o exhibited moderate in vivo antimalarial activity in a dose dependent fashion, its safety and survival rate were slightly better than that of positive drug. The preliminary SAR was obtained, meanwhile, molecular modeling result provided the key structural information to maintain the dual inhibitory activity, and was helpful for future dual inhibitors design.
- Huang, Huang,Lu, Weiqiang,Li, Xi,Cong, Xiaoli,Ma, Hongmei,Liu, Xiaofeng,Zhang, Yu,Che, Peng,Ma, Ruoqun,Li, Honglin,Shen, Xu,Jiang, Hualiang,Huang, Jin,Zhu, Jin
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supporting information; experimental part
p. 958 - 962
(2012/03/26)
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- CDK INHIBITORS CONTAINING A ZINC BINDING MOIETY
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The present invention relates to CDK inhibitors and their use in the treatment of cell proliferative diseases such as cancer. The compounds of the invention may further act as HDAC inhibitors.
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Page/Page column 85
(2009/04/25)
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- Preparation, Properties, Reactions, and Adenosine Receptor Affinities of Sulfophenylxanthine Nitrophenyl Esters: Toward the Development of Sulfonic Acid Prodrugs with Peroral Bioavailability
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Many currently known antagonists for P2 purinergic receptors are anionic molecules bearing one or several phenylsulfonate groups. Among the P1 (adenosine) receptor antagonists, the xanthine phenylsulfonates are a potent class of compounds. Due to their high acidity, phenylsulfonates are negatively charged at physiologic pH values and do not easily penetrate cell membranes. The present study was aimed at developing lipophilic, perorally bioavailable prodrugs of sulfonates by converting them into chemically stable nitrophenyl esters. Initial stability tests at different pH values using nitrophenyl tosylates as model compounds showed that m-nitrophenyl esters were stable over a wide pH range, while the ortho and para isomers were less stable under strongly acidic or basic conditions. A series of m- and p-nitrophenyl esters of p-sulfophenylxanthine derivatives were synthesized as model compounds. The target xanthine derivatives were obtained in high yields by condensation of the appropriate 5,6-diaminouracils with 4-(nitrophenoxysulfonyl)benzoic acids in the presence of a carbodiimide, followed by ring closure with polyphosphoric acid trimethylsilyl ester. The chemical and enzymatic stability of the m-nitrophenyl esters was investigated in vitro by means of capillary electrophoresis. High stability in aqueous solution, in artificial gastric acid, and in serum was observed. However, compound 5d, used as a prototypic xanthine m-nitrophenylsulfonate, was hydrolyzed by rat liver homogenate indicating an enzymatic pathway of hydrolysis. Thus, nitrophenyl esters of sulfonic acids have a potential as peroral prodrugs of drugs bearing a sulfonate group. The nitrophenyl esters of sulfophenylxanthines were additionally investigated for their adenosine receptor affinities. They showed high affinity at A 2, A2A, and A2B, but not at A3 ARs. One of the most potent compounds was 1-propyl-8-[4-[[p-nitrophenoxy]sulfonyl]-phenyl]xanthine (9d), a mixed A 1/A2B antagonist (KiA1 3.6 nM, KiA2B 5.4 nM) selective versus the other subtypes. As a further result of this study, the m-nitrophenoxy group was found to be a suitable protecting group for sulfonates in organic synthesis due to its high lipophilicity and stability; it can be split off under strongly basic conditions. This new protection strategy allowed for the upscaling of the synthesis of 1-propyl-8-p-sulfophenylxanthine (PSB-1115), a selective A 2B antagonist.
- Yan, Luo,Müller, Christa E.
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p. 1031 - 1043
(2007/10/03)
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