1571-08-0Relevant articles and documents
Cobalt Corroles as Electrocatalysts for Water Oxidation: Strong Effect of Substituents on Catalytic Activity
Neuman, Nicolás I.,Albold, Uta,Ferretti, Eleonora,Chandra, Shubhadeep,Steinhauer, Simon,R?ner, Paul,Meyer, Franc,Doctorovich, Fabio,Vaillard, Santiago E.,Sarkar, Biprajit
, p. 16622 - 16634 (2020)
Two Co(III) complexes (1Py2 and 2Py2) of new corrole ligands H3L1 (5,15-bis(p-methylcarboxyphenyl)-10-(o-methylcarboxyphenyl)corrole) and H3L2 (5,15-bis(p-nitrophenyl)-10-(o-methylcarboxyphenyl)corrole) with two apical pyridine ligands have been synthesized and thoroughly characterized by cyclic voltammetry, UV-vis-NIR, and EPR spectroscopy, spectroelectrochemistry, single-crystal X-ray diffraction studies, and DFT methods. Complexes 1Py2 and 2Py2 possess much lower oxidation potentials than cobalt(III)-tris-pentafluorophenylcorrole (Co(tpfc)) and similar corroles containing pentafluorophenyl (C6F5) substituents, thus allowing access to high oxidation states of the former metallocorroles using mild chemical oxidants. The spectroscopic (UV-vis-NIR and EPR) and electronic properties of several oxidation states of these complexes have been determined by a combination of the mentioned methods. Complexes 1Py2 and 2Py2 undergo three oxidations within 1.3 V vs FcH+/FcH in MeCN, and we show that both complexes catalyze water oxidation in an MeCN/H2O mixture upon the third oxidation, with kobs (TOF) values of 1.86 s-1 at 1.29 V (1Py2) and 1.67 s-1 at 1.37 V (2Py2). These values are five times higher than previously reported TOF values for C6F5-substituted cobalt(III) corroles, a finding we ascribe to the additional charge in the corrole macrocycle due to the increased oxidation state. This work opens up new possibilities in the study of metallocorrole water oxidation catalysts, particularly by allowing spectroscopic probing of high-oxidation states and showing strong substituent-effects on catalytic activity of the corrole complexes.
-
Kawabe et al.
, p. 4210 (1972)
-
One-pot conversion of activated alcohols into terminal alkynes using manganese dioxide in combination with the Bestmann-Ohira reagent
Quesada, Ernesto,Taylor, Richard J.K.
, p. 6473 - 6476 (2005)
The direct conversion of activated primary alcohols into terminal alkynes through a sequential one-pot, two-step process involving oxidation with manganese dioxide and then treatment with the Bestmann-Ohira reagent is described. This transformation proceeds efficiently (59-99% yield) under mild reaction conditions with a range of benzylic, heterocyclic and propargylic alcohols. A tandem variant is also described, which is successful only with highly activated substrates.
Synthesis of Carboxamide-Containing Tranylcypromine Analogues as LSD1 (KDM1A) Inhibitors Targeting Acute Myeloid Leukemia
Teresa Borrello, Maria,Benelkebir, Hanae,Lee, Adam,Hin Tam, Chak,Shafat, Manar,Rushworth, Stuart A.,Bowles, Kristian M.,Douglas, Leon,Duriez, Patrick J.,Bailey, Sarah,Crabb, Simon J.,Packham, Graham,Ganesan
, p. 1316 - 1324 (2021)
Lysine-specific demethylase 1 (LSD1/KDM1A) oxidatively removes methyl groups from histone proteins, and its aberrant activity has been correlated with cancers including acute myeloid leukemia (AML). We report a novel series of tranylcypromine analogues with a carboxamide at the 4-position of the aryl ring. These compounds, such as 5 a and 5 b with benzyl and phenethylamide substituents, respectively, had potent sub-micromolar IC50 values for the inhibition of LSD1 as well as cell proliferation in a panel of AML cell lines. The dose-dependent increase in cellular expression levels of H3K4me2, CD86, CD11b and CD14 supported a mechanism involving LSD1 inhibition. The tert-butyl and ethyl carbamate derivatives of these tranylcypromines, although inactive in LSD1 inhibition, were of similar potency in cell-based assays with a more rapid onset of action. This suggests that carbamates can act as metabolically labile tranylcypromine prodrugs with superior pharmacokinetics.
Highly atom efficient synthesis of 2,2,4,5-tetrasubstituted 3(2H)-furanones having both hydroxyl and amino substituents
Antony, Jesna,Mathai, Sindhu,Natarajan, Rakesh,P. Musthafa, Sumi,Rappai, John P.,S. Devaky, Karakkattu
supporting information, (2022/02/25)
We have developed a highly atom efficient synthesis of tetrasubstituted 3(2H)-furanones from easily accessible starting materials such as C,N-diarylaldonitrones and dibenzoylacetylene. Control experiments revealed that reaction of aldonitrones having electron-withdrawing groups on the C-aryl substituent in polar aprotic solvents exhibited high product selectivity while reaction temperature has only a negligible effect on product yield and selectivity.
Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
, p. 3498 - 3506 (2021/04/07)
In many metal catalyses, the traditional strategy of removing chloride ions is to add silver salts via anion exchange to obtain highly active catalysts. Herein, we reported an alternative strategy of removing chloride anions from ruthenium trichloride using an organic [P+-N-] zwitterionic compound via multiple hydrogen bond interactions. The resultant organic-metal hybrid catalytic system has successfully been applied to the aerobic oxidation of alcohols, tetrahydroquinolines, and indolines under mild conditions. The performance of zwitterion is far superior to that of many other common Lewis bases or Br?nsted bases. Mechanistic studies revealed that the zwitterion triggers the dissociation of chloride from ruthenium trichloride via nonclassical hydrogen bond interaction. Preliminary studies show that the zwitterion is applicable to catalytic transfer semi-hydrogenation.
4CzIPN catalyzed photochemical oxidation of benzylic alcohols
Zhang, Heng,Guo, Tianyun,Wu, Mingzhong,Huo, Xing,Tang, Shouchu,Wang, Xiaolei,Liu, Jian
supporting information, (2021/02/20)
A green photoredox oxidation of benzylic primary and secondary alcohols to aldehydes and ketones with air as an oxidant was reported. The oxidation shows broad substrate scope and excellent selectivity over benzylic alcohols to the aliphatic alcohols. Further mechanistic studies revealed a quinuclidine mediated HAT process, and blue LEDs promoted 4CzlPN (1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene) photoredox cycle were involved in our oxidation.