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Carsten Bolm - One of the best experts on this subject based on the ideXlab platform.
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1 2 benzothiazines from sulfoximines and allyl methyl carbonate by rhodium catalyzed cross coupling and oxidative cyclization
Organic Letters, 2017Co-Authors: Jian Wen, Deo Prakash Tiwari, Carsten BolmAbstract:4-Unsubstituted 1,2-benzothiazines are prepared from sulfoximines and allyl methyl carbonate by Rh(III)-catalyzed domino allylation/oxidative cyclization. A wide range of functional groups on the sulfoximine are tolerated. A plausible mechanism is proposed, and chemical modifications of the products have been explored.
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Rhodium(III)-Catalyzed Ortho Halogenations of N‑Acylsulfoximines and Synthetic Applications toward Functionalized Sulfoximine Derivatives
2017Co-Authors: Ying Cheng, Wanrong Dong, Kanniyappan Parthasarathy, Carsten BolmAbstract:Rhodium(III)-catalyzed ortho brominations and iodinations of N-acylsulfoximines by C–H bond activations have been developed. Subsequent product functionalizations involving cross-coupling reactions provide alkynylated sulfoximine derivatives and benzothiazines with wide potential for further synthetic applications
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1,2-Benzothiazines from Sulfoximines and Allyl Methyl Carbonate by Rhodium-Catalyzed Cross-Coupling and Oxidative Cyclization
2017Co-Authors: Jian Wen, Deo Prakash Tiwari, Carsten BolmAbstract:4-Unsubstituted 1,2-benzothiazines are prepared from sulfoximines and allyl methyl carbonate by Rh(III)-catalyzed domino allylation/oxidative cyclization. A wide range of functional groups on the sulfoximine are tolerated. A plausible mechanism is proposed, and chemical modifications of the products have been explored
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iron catalyzed acylative dealkylation of n alkylsulfoximines
European Journal of Organic Chemistry, 2015Co-Authors: Philip Lamers, Daniel L Priebbenow, Carsten BolmAbstract:As a result of our recent investigations into the N-functionalization of sulfoximines, an iron-catalyzed dealkylative acylation of N-alkylsulfoximines has been developed. This process involves a Polonovski-type dealkylation of an N-alkylated sulfoximine to afford a reactive intermediate that is trapped in the presence of a suitable aldehyde or anhydride to afford N-acyl- and N-aroylsulfoximine derivatives in one pot. Subsequent cleavage of the acyl or aroyl group under acidic conditions generates a synthetically valuable NH-sulfoximine.
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sulfoximine and sulfilimine based dapson analogues syntheses and bioactivities
Synlett, 2012Co-Authors: Xiaoyun Chen, Helmut Buschmann, Carsten BolmAbstract:Sulfoximine- and sulfilimine-based diamino-diphenyl sulfone (DAPSON) analogues have been prepared and their COX-1 and COX-2 inhibition potencies as well as LTB4 and TNF binding properties were studied. Furthermore, their antiproliferative activities on cancer cell growth were investigated. Neither compounds showed significant bioactivities.
Hansjoachim Gais - One of the best experts on this subject based on the ideXlab platform.
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sulfoximine based modular enantioselective synthesis of azaspirocycles featuring sulfoximine displacement dianion cycloalkylation rcm and n acyliminium ion formation
European Journal of Organic Chemistry, 2014Co-Authors: Adeline Kohler, Gerhard Raabe, Jan Runsink, Franz Kohler, Hansjoachim GaisAbstract:We describe a modular, enantioselective synthesis of functionalised azaspirocycles with a range of ring sizes. The synthesis exploits the special features of sulfoximines, including chirality, carbanion-stabilisation, nucleophilicity, and nucleofugacity. Diastereoselective intramolecular amination of hydroxyalkyl-substituted cycloalkenylsulfoximines by the carbamate method gave bicyclic oxazinanones containing an amino-substituted tertiary C atom. Cycloalkylation of the corresponding C,N-dianions with biselectrophiles afforded sulfoximine-substituted spirocycles. Monoalkylation of the C,N-dianions with functionalised electrophiles, having a double bond and acetal group, furnished the corresponding C-alkylated bicyclic sulfoximines. Displacement of the sulfoximine group of bicyclic and spirocyclic sulfoximines by haloformate reactions gave the corresponding halides (Cl, I). Alkylation of the bicyclic halides with functionalised cuprates and reduction of the sulfoximine-substituted bicycles, carrying an alkyl group at the Cα atom, gave starting materials for a step-wise construction of the heterocyclic ring. Ring-closing metathesis of a bicyclic C,N-dienyl derivative furnished the corresponding spirocycle with an unsaturated piperidine ring. Cyclisation of an acetal group containing bicyclic oxazinanone gave spirocycles containing O,N-acetal and enamide groups. The diastereoselective reaction of a spirocyclic O,N-acetal with an allylsilane furnished the corresponding spirocycle, carrying an allyl group at the C atom adjacent to the N atom. Attempts to lithiate a bicyclic carbamate at the CH2 group adjacent to the N atom were not successful.
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ring closing metathesis of sulfoximine substituted n tethered trienes modular asymmetric synthesis of medium ring nitrogen heterocycles
ChemInform, 2011Co-Authors: Vishal A Mahajan, Hansjoachim GaisAbstract:Sulfoximine-substituted N-tethered trienes, synthesized from the corresponding homoallylic amines, undergo ruthenium-catalyzed ring-closing reaction to give the desired heterocycles with high diastereoselectivity.
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ring closing metathesis of sulfoximine substituted n tethered trienes modular asymmetric synthesis of medium ring nitrogen heterocycles
Chemistry: A European Journal, 2011Co-Authors: Vishal A Mahajan, Hansjoachim GaisAbstract:A synthesis of sulfoximine-substituted medium-ring nitrogen heterocycles (MRNHs) having a high degree of substitution has been developed. Its key steps are the modular asymmetric synthesis of sulfoximine-substituted N-tethered trienes and their Ru-catalyzed ring-closing metathesis (RCM) reaction. The highly substituted N-tethered trienes were obtained enantio- and diastereopure through 1) the diastereoselective aminoalkylation of sulfoximine-substituted allyltitanium complexes with N-tert-butylsulfonyliminoester, 2) N-allylation of homoallylic N-sulfonyl amines, 3) allylation, hydroxylalkylation, and formylation of α-lithioalkenylsulfoximines, and 4) allylation of α-formylalkenylsulfoximines. The Ru-catalyzed RCM reaction of the sulfoximine-substituted 1,7,10- and 1,7,12-trienes stereoselectively afforded the corresponding nine-, ten-, and eleven-membered MRNHs in good yields. An interesting difference in reactivity was noted in the case of a sulfoximine-substituted 1,7,10-triene and its corresponding 1,10-diene. While the triene readily underwent a RCM reaction, the diene reacted only in the presence of Ti(OiPr)(4) under formation of the corresponding MRNH. The feasibility of a removal of the sulfoximine auxiliary and the N-sulfonyl protecting group from the MRNHs were demonstrated through reduction and cleavage, respectively, of a nine-membered heterocycle, both of which proceeded readily and gave the corresponding cyclic alkene and amine, respectively.
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asymmetric modular synthesis of highly functionalized medium sized carbocycles and lactones via ring closing metathesis of sulfoximine substituted trienes
Journal of the American Chemical Society, 2006Co-Authors: Michal Lejkowski, Hansjoachim Gais, Prabal Banerjee, Cornelia VermeerenAbstract:A modular asymmetric synthesis of medium-sized carbocycles and lactones has been developed that affords highly substituted 7-, 9-, and 11-membered rings. The key steps are (1) the highly diastereoselective synthesis of sulfoximine-substituted homoallylic alcohols from allylic sulfoximines and unsaturated as well as saturated aldehydes, (2) an E-stereoselective alkylation and hydroxyalkylation of sulfoximine-substituted alkenyllithium derivatives, (3) the esterification of sulfoximine-substituted homoallylic alcohols, and (4) the ring-closing metathesis reaction of sulfoximine-substituted trienes with the ruthenium catalyst 8. Two examples for the further synthetic elaboration of the sulfoximine-substituted carbocycles are provided. The selective cleavage of the tert-butyldimethylsilyl group of 12 in the presence of the triethylsilyl group afforded the allylic alcohol 18 which was oxidized to enone 19. A cross-coupling reaction of the sulfoximine-substituted carbocycle 9 with LiCuMe2 furnished the methyl-s...
Vishal A Mahajan - One of the best experts on this subject based on the ideXlab platform.
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ring closing metathesis of sulfoximine substituted n tethered trienes modular asymmetric synthesis of medium ring nitrogen heterocycles
ChemInform, 2011Co-Authors: Vishal A Mahajan, Hansjoachim GaisAbstract:Sulfoximine-substituted N-tethered trienes, synthesized from the corresponding homoallylic amines, undergo ruthenium-catalyzed ring-closing reaction to give the desired heterocycles with high diastereoselectivity.
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ring closing metathesis of sulfoximine substituted n tethered trienes modular asymmetric synthesis of medium ring nitrogen heterocycles
Chemistry: A European Journal, 2011Co-Authors: Vishal A Mahajan, Hansjoachim GaisAbstract:A synthesis of sulfoximine-substituted medium-ring nitrogen heterocycles (MRNHs) having a high degree of substitution has been developed. Its key steps are the modular asymmetric synthesis of sulfoximine-substituted N-tethered trienes and their Ru-catalyzed ring-closing metathesis (RCM) reaction. The highly substituted N-tethered trienes were obtained enantio- and diastereopure through 1) the diastereoselective aminoalkylation of sulfoximine-substituted allyltitanium complexes with N-tert-butylsulfonyliminoester, 2) N-allylation of homoallylic N-sulfonyl amines, 3) allylation, hydroxylalkylation, and formylation of α-lithioalkenylsulfoximines, and 4) allylation of α-formylalkenylsulfoximines. The Ru-catalyzed RCM reaction of the sulfoximine-substituted 1,7,10- and 1,7,12-trienes stereoselectively afforded the corresponding nine-, ten-, and eleven-membered MRNHs in good yields. An interesting difference in reactivity was noted in the case of a sulfoximine-substituted 1,7,10-triene and its corresponding 1,10-diene. While the triene readily underwent a RCM reaction, the diene reacted only in the presence of Ti(OiPr)(4) under formation of the corresponding MRNH. The feasibility of a removal of the sulfoximine auxiliary and the N-sulfonyl protecting group from the MRNHs were demonstrated through reduction and cleavage, respectively, of a nine-membered heterocycle, both of which proceeded readily and gave the corresponding cyclic alkene and amine, respectively.
Anders Karlen - One of the best experts on this subject based on the ideXlab platform.
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structural basis for the inhibition of mycobacterium tuberculosis glutamine synthetase by novel atp competitive inhibitors
Journal of Molecular Biology, 2009Co-Authors: Mikael Nilsson, Wojciech Krajewski, Sujan Yellagunda, Savitha Prabhumurthy, Gayathri N Chamarahally, Chandrasekharan Siddamadappa, Bachally R Srinivasa, Samir Yahiaoui, Mats Larhed, Anders KarlenAbstract:Glutamine synthetase (GS, EC 6.3.1.2; also known as gamma-glutamyl:ammonia ligase) catalyzes the ATP-dependent condensation of glutamate and ammonia to form glutamine. The enzyme has essential roles in different tissues and species, which have led to its consideration as a drug or an herbicide target. In this article, we describe studies aimed at the discovery of new antimicrobial agents targeting Mycobacterium tuberculosis, the causative pathogen of tuberculosis. A number of distinct classes of GS inhibitors with an IC(50) of micromolar value or better were identified via high-throughput screening. A commercially available purine analogue similar to one of the clusters identified (the diketopurines), 1-[(3,4-dichlorophenyl)methyl]-3,7-dimethyl-8-morpholin-4-yl-purine-2,6-dione, was also shown to inhibit the enzyme, with a measured IC(50) of 2.5+/-0.4 microM. Two X-ray structures are presented: one is a complex of the enzyme with the purine analogue alone (2.55-A resolution), and the other includes the compound together with methionine sulfoximine phosphate, magnesium and phosphate (2.2-A resolution). The former represents a relaxed, inactive conformation of the enzyme, while the latter is a taut, active one. These structures show that the compound binds at the same position in the nucleotide site, regardless of the conformational state. The ATP-binding site of the human enzyme differs substantially, explaining why it has an approximately 60-fold lower affinity for this compound than the bacterial GS. As part of this work, we devised a new synthetic procedure for generating l-(SR)-methionine sulfoximine phosphate from l-(SR)-methionine sulfoximine, which will facilitate future investigations of novel GS inhibitors.
Jian Wen - One of the best experts on this subject based on the ideXlab platform.
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1 2 benzothiazines from sulfoximines and allyl methyl carbonate by rhodium catalyzed cross coupling and oxidative cyclization
Organic Letters, 2017Co-Authors: Jian Wen, Deo Prakash Tiwari, Carsten BolmAbstract:4-Unsubstituted 1,2-benzothiazines are prepared from sulfoximines and allyl methyl carbonate by Rh(III)-catalyzed domino allylation/oxidative cyclization. A wide range of functional groups on the sulfoximine are tolerated. A plausible mechanism is proposed, and chemical modifications of the products have been explored.
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1,2-Benzothiazines from Sulfoximines and Allyl Methyl Carbonate by Rhodium-Catalyzed Cross-Coupling and Oxidative Cyclization
2017Co-Authors: Jian Wen, Deo Prakash Tiwari, Carsten BolmAbstract:4-Unsubstituted 1,2-benzothiazines are prepared from sulfoximines and allyl methyl carbonate by Rh(III)-catalyzed domino allylation/oxidative cyclization. A wide range of functional groups on the sulfoximine are tolerated. A plausible mechanism is proposed, and chemical modifications of the products have been explored
