284670-71-9Relevant academic research and scientific papers
Catalytic Synthesis of N-Heterocycles via Direct C(sp3)-H Amination Using an Air-Stable Iron(III) Species with a Redox-Active Ligand
Bagh, Bidraha,Broere, Dani?l L. J.,Sinha, Vivek,Kuijpers, Petrus F.,Van Leest, Nicolaas P.,De Bruin, Bas,Demeshko, Serhiy,Siegler, Maxime A.,Van Der Vlugt, Jarl Ivar
supporting information, p. 5117 - 5124 (2017/05/04)
Coordination of FeCl3 to the redox-active pyridine-aminophenol ligand NNOH2 in the presence of base and under aerobic conditions generates FeCl2(NNOISQ) (1), featuring high-spin FeIII and an NNOISQ radical ligand. The complex has an overall S = 2 spin state, as deduced from experimental and computational data. The ligand-centered radical couples antiferromagnetically with the Fe center. Readily available, well-defined, and air-stable 1 catalyzes the challenging intramolecular direct C(sp3)-H amination of unactivated organic azides to generate a range of saturated N-heterocycles with the highest turnover number (TON) (1 mol% of 1, 12 h, TON = 62; 0.1 mol% of 1, 7 days, TON = 620) reported to date. The catalyst is easily recycled without noticeable loss of catalytic activity. A detailed kinetic study for C(sp3)-H amination of 1-azido-4-phenylbutane (S1) revealed zero order in the azide substrate and first order in both the catalyst and Boc2O. A cationic iron complex, generated from the neutral precatalyst upon reaction with Boc2O, is proposed as the catalytically active species.
Cobalt-Porphyrin-Catalysed Intramolecular Ring-Closing C?H Amination of Aliphatic Azides: A Nitrene-Radical Approach to Saturated Heterocycles
Kuijpers, Petrus F.,Tiekink, Martijn J.,Breukelaar, Willem B.,Broere, Dani?l L. J.,van Leest, Nicolaas P.,van der Vlugt, Jarl Ivar,Reek, Joost N. H.,de Bruin, Bas
supporting information, p. 7945 - 7952 (2017/06/19)
Cobalt-porphyrin-catalysed intramolecular ring-closing C?H bond amination enables direct synthesis of various N-heterocycles from aliphatic azides. Pyrrolidines, oxazolidines, imidazolidines, isoindolines and tetrahydroisoquinoline can be obtained in good to excellent yields in a single reaction step with an air- and moisture-stable catalyst. Kinetic studies of the reaction in combination with DFT calculations reveal a metallo-radical-type mechanism involving rate-limiting azide activation to form the key cobalt(III)-nitrene radical intermediate. A subsequent low barrier intramolecular hydrogen-atom transfer from a benzylic C?H bond to the nitrene-radical intermediate followed by a radical rebound step leads to formation of the desired N-heterocyclic ring products. Kinetic isotope competition experiments are in agreement with a radical-type C?H bond-activation step (intramolecular KIE=7), which occurs after the rate-limiting azide activation step. The use of di-tert-butyldicarbonate (Boc2O) significantly enhances the reaction rate by preventing competitive binding of the formed amine product. Under these conditions, the reaction shows clean first-order kinetics in both the [catalyst] and the [azide substrate], and is zero-order in [Boc2O]. Modest enantioselectivities (29–46 % ee in the temperature range of 100–80 °C) could be achieved in the ring closure of (4-azidobutyl)benzene using a new chiral cobalt-porphyrin catalyst equipped with four (1S)-(?)-camphanic-ester groups.
Design and synthesis of macrocyclic peptidyl hydroxamates as peptide deformylase inhibitors
Shen, Gang,Zhu, Jinge,Simpson, Anthony M.,Pei, Dehua
, p. 3060 - 3063 (2008/12/23)
Macrocyclic peptidyl hydroxamates were designed, synthesized, and evaluated as peptide deformylase (PDF) inhibitors. The most potent compound exhibited tight, slow-binding inhibition of Escherichia coli PDF (KI* = 4.4 nM) and had pot
Macrocyclic inhibitors for peptide deformylase: A structure-activity relationship study of the ring size
Hu, Xubo,Nguyen, Kiet T.,Jiang, Vernon C.,Lofland, Denene,Moser, Heinz E.,Pei, Dehua
, p. 4941 - 4949 (2007/10/03)
Peptide deformylase (PDF) catalyzes the removal of the N-terminal formyl group from newly synthesized polypeptides in eubacteria. Its essential role in bacterial cells but not in mammalian cells makes it an attractive target for antibacterial drug design. We have previously reported an N-formylhydroxylamine- based, metal-chelating macrocyclic PDF inhibitor, in which the P 1′ and P3′ side chains are covalently joined. In this work, we have carried out a structure-activity relationship study on the size of the macrocycle and found that 15-17-membered macrocycles are optimal for binding to the PDF active site. Unlike the acyclic compounds, which are simple competitive inhibitors, the cyclic compounds all act as slow-binding inhibitors. As compared to their acyclic counterparts, the cyclic inhibitors displayed 20-50-fold higher potency against the PDF active site (K I* as low as 70 pM), improved selectivity toward PDF, and improved the metabolic stability in rat plasma. Some of the macrocyclic inhibitors had potent, broad spectrum antibacterial activity against clinically significant Gram-positive and Gram-negative pathogens. These results suggest that the macrocyclic scaffold provides an excellent lead for the development of a new class of antibiotics.
Efficient synthesis of medium-sized cyclic amines by means of 2-nitrobenzenesulfonamide
Kan, Toshiyuki,Kobayashi, Hideki,Fukuyama, Tohru
, p. 697 - 699 (2007/10/03)
Construction of medium-sized cyclic amines using 2-nitrobenzenesulfonamides is described. Under either conventional alkylation or Mitsunobu reaction conditions, the cyclization reaction proceeded efficiently to give eight- to ten-membered rings.
Efficient macrocyclization by means of 2-nitrobenzenesulfonamide and total synthesis of lipogrammistin-A
Kan, Toshiyuki,Fujiwara, Akiko,Kobayashi, Hideki,Fukuyama, Tohru
, p. 6267 - 6276 (2007/10/03)
Synthesis of medium- and large-sized cyclic amines using alkylation with 2-nitrobenzenesulfonamides is described. Using either conventional alkylation procedures or Mitsunobu conditions, the cyclization reaction proceeded in a highly efficient manner. The usefulness of this methodology has been fully demonstrated in the total synthesis of lipogrammistin-A (9), an 18-membered cyclic polyamine.
