24395-14-0Relevant articles and documents
Cascade reactions of indigo with oxiranes and aziridines: efficient access to dihydropyrazinodiindoles and spiro-oxazocinodiindoles
Butler, Nicholas M.,Hendra, Rudi,Bremner, John B.,Willis, Anthony C.,Lucantoni, Leonardo,Avery, Vicky M.,Keller, Paul A.
, p. 6006 - 6016 (2018)
The base-initiated alkylation of the abundant natural dye indigo 1 with ring-strained electrophiles results in the unprecedented, one-pot synthesis of functionalised dihydropyrazino[1,2-a:4,3-a′]diindoles, dihydroepoxy[1,5]oxazocino[5,4-a:3,2-b′]diindoles, and dihydrodiazepino[1,2-a:4,3-a′]diindoles, resulting from intramolecular ring opening-expansion cyclisation processes of their parent oxiranes and aziridines. Regiochemical and stereochemical aspects of the reactions are reported together with integrated mechanistic proposals. This new indigo cascade chemistry should have broad applicability in the synthesis of chemical architectures, not readily-accessible by other means. The three-step synthesis of the useful synthetic precursor (R)-2-(chloromethyl)-1-tosylaziridine 14 is also described. Initial biological activity investigations into these new 2,2′-dindolyl-based heterocyclic derivatives revealed potent, selective antiplasmodial activity in vitro for several isolated structures, with IC50 values as low as 76.6 nM for (±)-8, while demonstrating low human cell toxicity.
Silver(I) and Copper(I) Complexes of Semi-Bulky Nitrogen-Confused C-Scorpionates
Gardinier, James R.,Jahan, Fathiya,Lindeman, Sergey V.,Meise, Kristen J.,Wang, Denan
, (2020)
Two new sterically demanding nitrogen-confused C-scorpionate ligands with a bis(3,5-diisopropylpyrazol-1-yl)methyl group bound to the 3- position of a normal pyrazole (HLiPr2) or an N-toluenesulfonyl pyrazole (TsLiPr2) have been prepared. Reactions between the ligands (xLiPr2) and silver trifluoromethanesulfonate, AgOTf, gave four new compounds of the types [Ag(xLiPr2)](OTf) (x = Ts, 1a; x = H, 2a) or [Ag(xLiPr2)2](OTf) (x = Ts, 1b; x = H, 2b) depending on the initial metal:ligand ratio. Similarly, the reactions with [Cu(CH3CN)4](PF6) produce four new compounds of the type [Cu(xLiPr2)(CH3CN)](PF6) (x = Ts, 3a; x = H, 4a) or [Cu(xLiPr2)2](PF6) (x = Ts, 3b; x = H, 4b). The solid-state structures of four derivatives (1a·acetone, 3a, 3b·CH2Cl2, and 4b·2THF) were determined by single-crystal X-ray diffraction while all complexes were characterized in CH3CN solution by NMR spectroscopy and ESI(+) MS. The eight new complexes catalyze the aziridination of styrene. The copper complexes were generally (but not exclusively) more active catalysts than their silver counterparts.
Catalytic aziridination of styrene with copper complexes of substituted 3,7-Diazabicyclo[3.3.1]nonanones
Comba, Peter,Merz, Michael,Pritzkow, Hans
, p. 1711 - 1718 (2003)
The copper(II) complexes of five bispidine-type ligands {3,7- diazabicyclo[3.3.1]nonanone; three tetradentate ligands with 2-pyridyl (L1), 6-methyl-2-pyridyl (L2) or 2-imidazolyl-3-methyl (L3) substituents in 2,4-positions; two pentadentate derivatives of L1 with an additional 2-methylpyridine substituent at N3 (L4) or N7 (L5)} have, with one co-ligand (Cl-), a ligand-enforced square pyramidal (L1,2,3) or octahedral (L4,5) geometry. The main structural properties of three of the five [Cu(L)(Cl)]+ complexes (L1,2,3) are very similar, with Cu-N3 A (trans to N3); with L2 Cu-N3 ～ Cu-N7 and Cu-Cl = 2.22 A (trans to N7); with L5 Cu-N3 A (trans to N7). These structural patterns lead to considerable differences in ligand field and electrochemical properties (range of E° of approx. 500mV), and the reactivities of the copper(II) complexes as aziridination catalysts (styrene, PhINTs, CH3CN) are strikingly different. While the complex with L2 is very efficient, the activities of those with L1 and L3 are reduced to approx. 50% and 30%, respectively, and those with L4 and L5 are inactive. The fact that the maximum TON (maximum turnover number) of CuIIL2 (19) is much smaller than the maximum TON of CuIL2 (47) suggests that in the active form the catalysts are in the CuI oxidation state, and that the differences in reduction potentials are of major importance for catalysis. The result that CuL4,5 have no activity in the CuII state and only a small activity in the reduced form indicates that, apart from the reduction potentials, steric effects might also be of importance. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
Reaction Chemistry of Silver(I) Trifluoromethanesulfonate Complexes of Nitrogen-Confused C-Scorpionates
Gardinier, James R.,Meise, Kristin J.,Jahan, Fathiya,Lindeman, Sergey V.
, p. 1572 - 1589 (2018)
Two new C-scorpionate ligands with a bis(3,5-dimethylpyrazol-1-yl)methyl group bound to the 3 position of either an N-tosyl (TsL?) or an N-H pyrazole (HL?) ring have been prepared. The silver(I) complexes of these new ligands and the two previously reported analogous ligands with unsubstituted bis(pyrazol-1-yl)methyl groups (TsL and HL) in both 1:1 and 2:1 ligand/metal ratios were investigated to explore the effects of ligand sterics on their physical and chemical properties. The structurally characterized derivatives of the type [Ag(L)2](OTf) are four-coordinate, where the confused pyrazolyl is not bound to the metal. On the other hand, three 1:1 complexes [Ag(L)](OTf) had all pyrazolyls bound, while the μ-κ1,κ1-TsL derivative had an unbound confused pyrazolyl. The molecularity of the latter four ranged from polymeric to dimeric to monomeric in the solid with increasing steric bulk of the ligand. The utility of these complexes in stoichiometric ligand-transfer reactions and in styrene aziridination was demonstrated. Thus, tricarbonylmanganese(I) complexes were prepared as kinetically inert models for comparative solution diffusion NMR studies. Also, [Fe(HL)2](OTf)2 was prepared for similar reasons and to compare the effects of anion on spin-crossover properties.
An Organocatalytic Kinetic Resolution of Aziridines by Thiol Nucleophiles
Sun, Song,Wang, Zhaobin,Li, Shijia,Zhou, Cong,Song, Lijuan,Huang, Hai,Sun, Jianwei
supporting information, p. 554 - 558 (2021/02/03)
We report the first organocatalytic kinetic resolution of unactivated aziridines by sulfur nucleophiles with excellent enantioselectivity. A suitable chiral phosphoric acid was found to catalyze the intermolecular ring opening under mild conditions, furni
Catalyst-Free Visible-Light-Mediated Iodoamination of Olefins and Synthetic Applications
Engl, Sebastian,Reiser, Oliver
supporting information, p. 5581 - 5586 (2021/07/26)
Herein we report a catalyst- and metal-free visible-light-mediated protocol enabling the iodoamination of miscellaneous olefins. This protocol is characterized by high yields under environmentally benign reaction conditions utilizing commercially available substrates and a green and biodegradable solvent. Furthermore, the protocol allows for late-stage functionalization of bioactive molecules and can be scaled to gram quantities of product, which offers manifold possibilities for further transformations, including morpholine, piperidine, pyrrolidine, and aziridine synthesis.
Make It Green: Copper-Catalyzed Olefin Aziridination in Water with an Iminoiodonane
Borrego, Elena,Pérez, Pedro J.,Caballero, Ana
, p. 5091 - 5095 (2021/12/09)
The copper complex Tp(CF3)2,BrCu(NCMe) efficiently catalyses the aziridination of olefins in water using PhI=NTs as the nitrene source, with identical activity than that observed when using dichloromethane as the solvent, under the same experim
