- 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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- Enantiomeric separations of chiral sulfonic and phosphoric acids with barium-doped cyclofructan selectors via an ion interaction mechanism
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New cyclofructan-6 (CF6)-based chiral stationary phases (CSPs) bind barium cations. As a result, the barium-complexed CSPs exhibit enantioselectivity toward 16 chiral phosphoric and sulfonic acids in the polar organic mode (e.g., methanol or ethanol mobile phase containing a barium salt additive). Retention is predominantly governed by a strong ionic interaction between the analyte and the complexed barium cation as well as hydrogen bonding with the cyclofructan macrocycle. The log k versus log [X], where [X] = the concentration of the barium counteranion, plots for LARIHC-CF6-P were linear with negative slopes demonstrating typical anion exchange behavior. The nature of the barium counteranion also was investigated (acetate, methanesulfonate, trifluoroacetate, and perchlorate), and the apparent elution strength was found to be acetate > methanesulfonate > trifluoroacetate > perchlorate. A theory based upon a double layer model was proposed wherein kosmotropic anions are selectively adsorbed to the cyclofructan macrocycle and attenuate the effect of the barium cation. van't Hoff studies for two analytes were conducted on the LARIHC-CF6-P for three of the barium salts (acetate, trifluoroacetate, and perchlorate), and the thermodynamic parameters governing retention and enantioselectivity are discussed. Interestingly, for the entropically driven separations, enantiomeric selectivity can increase at higher temperatures, even with decreasing retention.
- Smuts, Jonathan P.,Hao, Xin-Qi,Han, Zhaobin,Parpia, Curran,Krische, Michael J.,Armstrong, Daniel W.
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p. 1282 - 1290
(2014/02/14)
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- Influence of norbornanone substituents on both the Wagner-Meerwein skeletal rearrangements under sulfonation conditions and the diastereoselectivity of the corresponding N,N′-bis-fumaroyl sultams in uncatalyzed Diels-Alder cycloadditions to cyclopenta-1,3-diene
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The Wagner-Meerwein domino rearrangement of norbornanone skeletons, under sulfonation conditions, is strongly influenced by the absence of a gem-dimethyl moiety at C(7). As a result, sulfonation at C(10) is less efficient due to a divergent pathway in the intermediate double bond formation and/or isomerization. Furthermore, the absence of such a gem-dimethyl moiety in the corresponding norbornane[10,2]sultam derivatives, sterically influences the orientation of the SO(1) and SO(2) substituents, hence on the π-facial steric shielding of the thermodynamically more stable anti-s-cis N-alkenoyl dienophiles. As a consequence, their diastereoselective [4+2] cycloadditions to cyclopenta-1,3-diene, under nonchelating conditions, are not as efficient due to a less pseudo axial SO(1) and the consequent loss of pseudo C 2-symmetry.
- Pia?tek, Anna,Chapuis, Christian
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p. 4247 - 4249
(2013/07/26)
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- Identification of small molecule sulfonic acids as ecto-5'-nucleotidase inhibitors
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Ecto-5'-Nucleotidase inhibitors have great potential as anti-tumor agents. We have investigated biochemical properties of human and rat ecto-5'-Nucleotidases and characterized 19 small molecule sulfonic acid derivatives as potential inhibitors of ecto-5'-Nucleotidases. We identified 11 potent inhibitors of human and rat ecto-5'-Nucleotidases and checked their selectivity. Compound 10 (Sodium 2,4-dinitrobenzenesulfonate) with Ki value of 0.66 μM and 19 (N-(4- sulfamoylphenylcarbamothioyl) pivalamide) with Ki value of 0.78 μM were identified as the most potent inhibitors for human and rat ecto-5'-Nucleotidase, respectively. The present compounds have low molecular weights, water solubility and equal potency as compared to the reported inhibitors.
- Raza, Rabia,Saeed, Aamer,Lecka, Joanna,Sévigny, Jean,Iqbal, Jamshed
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p. 1133 - 1139
(2013/01/15)
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- Synthesis of novel chiral Schiff bases and their application in asymmetric transfer hydrogenation of prochiral ketones
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Novel chiral Schiff bases were synthesized from (+)-camphor, and their application to asymmetric transfer hydrogenation of prochiral ketones is described. The asymmetric transfer hydrogenation reaction could afford excellent conversion rates (up to 97.3%) and up to 27.3% enantiomeric excess.
- Zhou, Zhongqiang,Bian, Yongjun
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scheme or table
p. 682 - 687
(2010/11/04)
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- Polymorphic clopidogrel hydrogenesulphate form
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Novel orthorombic polymorph of clopidogrel hydrogen sulfate or hydrogen sulfate of methyl (+)-(S)-α-(2-chlorophenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine-5-acetate and a process for its preparation.
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- Dibenzonaphthyrones
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Dibenzonaphthyrone of formula (I) wherein A1and A2independently of each other are unsubstituted or mono- to tetra-substituted o-C6-C18arylene, with the proviso that formula (I) does not represent a dibenzonaphthyrone of the formula The invention further relates to processes for the preparation thereof, to the use thereof for colouring/pigmenting high-molecular-weight organic material and to substance compositions comprising dibenzonaphthyrones.
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- Resolution of Racemic Carboxylic and Sulfonic Acids via D-Xylose Derived New Cyclic Carbamate Reagents (Oxazolidin-2-ones)
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Two new chiral oxazolidin-2-ones have been easily prepared from D-xylose and studied as chiral derivatizing agents (CDA's) for the resolution of racemic carboxylic and sulfonic acids.The resultant diastereomers are readily separated by chromatographic methods and easily hydrolyzed to isolate the resolved materials in high optical purities and to return the CDA's for reuse.
- Koell, Peter,Luetzen, Arne
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- Optical resolution of the racemic modification of 2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide
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D-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide and 1-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide are produced by reacting d1-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide with optically active camphor-10-sulfonic acid or optically active 3-bromo-camphor-10-sulfonic acid as a resolving agent in a lower alkyl ester of acetic acid containing a lower alkyl carboxylic acid, thereby forming diastereomeric salts, and optically resolving said diastereomeric salts.
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- Process for the preparation of D(-)αphenylglycine
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The invention provides a process for the preparation of D(-)αphenylglycine by resolution of DLαphenylglycine by means of D(+)camphorsulfonic acid. The present process enables the preparation of D(-)αphenylglycine at a minimum loss of the very expensive starting materials, such as DLαphenylglycine and D(+)camphorsulfonic acid. The salts produced in this process are precipitated from the resolution filtrate and the filtrate may be discarded as effluent water without any danger to the environment.
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