- Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
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The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
- Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
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supporting information
(2020/07/15)
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- Highly Enantioselective Synthesis of Indazoles with a C3-Quaternary Chiral Center Using CuH Catalysis
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C3-substituted 1H-indazoles are useful and important substructures in many pharmaceuticals. Methods for direct C3-functionalization of indazoles are relatively rare, compared to reactions developed for the more nucleophilic N1 and N2 positions. Herein, we report a highly C3-selective allylation reaction of 1H-N-(benzoyloxy)indazoles using CuH catalysis. A variety of C3-allyl 1H-indazoles with quaternary stereocenters were efficiently prepared with high levels of enantioselectivity. Density functional theory (DFT) calculations were performed to explain the reactivity differences between indazole and indole electrophiles, the latter of which was used in our previously reported method. The calculations suggest that the indazole allylation reaction proceeds through an enantioselectivity-determining six-membered Zimmerman-Traxler-type transition state, rather than an oxidative addition/reductive elimination sequence, as we proposed in the case of indole alkylation. The enantioselectivity of the reaction is governed by both ligand-substrate steric interactions and steric repulsions involving the pseudoaxial substituent in the six-membered allylation transition state.
- Ye, Yuxuan,Kevlishvili, Ilia,Feng, Sheng,Liu, Peng,Buchwald, Stephen L.
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supporting information
p. 10550 - 10556
(2020/07/27)
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- Palladium-Catalyzed β-Mesylation of Simple Amide via Primary sp3 C-H Activation
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A β-mesylation of primary sp3 C-H bonds from simple amides with methanesulfonic anhydride (Ms2O) has been established successfully at 80 °C in a Pd(OAc)2 (catalyst)/K2S2O8 (oxidant)/CF3CH2OH (solvent) system. These amide substrates involve N-monosubstituted linear, branch, or cyclic alkanes, and electron-deficient benzyl compounds. The β-mesylated amide products can be converted easily to β-fluoroamides or β-lactams through inter- or intramolecular SN2 processes.
- Zhao, Ren,Lu, Wenjun
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p. 1768 - 1771
(2017/04/11)
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- Stereoelectronic effects in the reaction of aromatic substrates catalysed by: Halomonas elongata transaminase and its mutants
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A transaminase from Halomonas elongata and four mutants generated by an in silico-based design were recombinantly produced in E. coli, purified and applied to the amination of mono-substituted aromatic carbonyl-derivatives. While benzaldehyde derivatives were excellent substrates, only NO2-acetophenones were transformed into the (S)-amine with a high enantioselectivity. The different behaviour of wild-type and mutated transaminases was assessed by in silico substrate binding mode studies.
- Contente, Martina Letizia,Planchestainer, Matteo,Molinari, Francesco,Paradisi, Francesca
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p. 9306 - 9311
(2016/10/13)
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- Quinazolinones, Quinazolinthiones, and Quinazolinimines as Nitric Oxide Synthase Inhibitors: Synthetic Study and Biological Evaluation
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The synthesis of different compounds with a quinazolinone, quinazolinthione, or quinazolinimine skeleton and their in vitro biological evaluation as inhibitors of inducible and neuronal nitric oxide synthase (iNOS and nNOS) isoforms are described. These d
- Camacho, M. Encarnación,Chayah, Mariem,García, M. Esther,Fernández-Sáez, Nerea,Arias, Fabio,Gallo, Miguel A.,Carrión, M. Dora
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p. 638 - 650
(2016/08/27)
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- Iodine mediated deprotection of N-tert-butanesulfinyl amines: A functional group compatible method
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In the presence of iodine, a functional group compatible method for the deprotection of tert-butanesulfinyl and p-toluenesulfinyl units was developed. This journal is the Partner Organisations 2014.
- Chen, Wen,Ren, Jian,Wang, Minshou,Dang, Lingjing,Shen, Xianfu,Yang, Xiaodong,Zhang, Hongbin
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supporting information
p. 6259 - 6262
(2014/06/09)
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- Development of a novel class of pyrrolo-[1,2,5]benzothiadiazepine derivatives as potential anti-schistosomal agents
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Analogues of pyrrolo-[1,2,5]benzothiadiazepine were prepared and evaluated against Schistosoma japonica. The biological data revealed that most benzothiazepine derivatives show anti-schistosomal activity to some extent, while α-chloronation of the title compound and another bioisosteric derivative pyrrolo-[1,2,5]benzodiazepine displayed the most distinct worm killing activity. This study proved that benzodiazepine may serve as a novel structural skeleton for the development of anti-schistosomal agents.
- Chen, Jinglei,Sun, Weizhen,Yang, Jingjing,Sun, Huan,Wang, Zhixia,Dong, Lanlan,Qiao, Chunhua,Xia, Chao-Ming
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p. 3785 - 3787
(2013/07/25)
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- 4- [HETEROCYCLYL-METHYL] -8-FLUORO-QUINOLIN-2-ONES USEFUL AS NITRIC OXIDE SYNTHASE INHIBITORS
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Novel compounds of formulae (II, III) and pharmaceutical compositions have been found to inhibit inducible NOS synthase wherein: R4, R5, R6 and R7 are independently selected from the group consisting of hydrogen, lower alkyl, and halogen; and, R8 has the structure whrein X1, X2, X3, X4, X5, X6, R9, R13, R14 and n are as described herein.
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Page/Page column 53
(2009/04/25)
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- Amberlyst-15(H+)-NaBH4-LiCl: An effective reductor for oximes and hydrazones
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A simple and mild procedure reduces oximes and hydrazones on amberlyst 15(H+) support with LiCl-NaBH4 to the corresponding amines and hydrazines respectively in high yield and purity.
- Baruah, Bipul,Dutta, Manu P.,Boruah, Anima,Prajapati, Dipak,Sandhu, Jagir S.
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p. 409 - 410
(2007/10/03)
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- A new route to oligodeoxynucleoside phosphoramidates (P-NH2)
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We describe a new strategy to introduce phosphoramidate (P-NH2) internucleosidic linkages in oligonucleoside phosphodiesters using dimer building blocks. The P-NH2 function is generated under photolysis of the N-2-nitrobenzylphosphoramidate linkage (P-NHR). We achieved the synthesis of N-2-nitrobenzylphosphoramidate β and α-anomeric nucleotides dimers via either phosphoramidite or H-phosphonate chemistry, α-dimer (P-NHR) was incorporated at defined positions into α-oligonucleoside phosphodiesters and the P-NH2 linkage was liberated by U.V irradiation.
- Laurent, Alain,Debart, Francoise,Rayner, Bernard
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p. 5285 - 5288
(2007/10/03)
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- Piperazinopyrrolobenzodiazepines
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1,3,4,14b-Tetrahydro-2H,10H-pyrazino[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines, e.g. those of the formula STR1 R6 =H, alkyl, alkenyl, alkynyl, (cycloalkyl or HO)-alkyl R7 =H, halo or CF3 acyl derivatives, N-oxides, quaterna
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