25784-85-4Relevant articles and documents
Synthesis of a new series of Ni(II), Cu(II), Co(II) and Pd(II) complexes with an ONS donor Schiff base: Crystal structure, DFT study and catalytic investigation of palladium and nickel complexes towards deacylative sulfenylation of active methylenes and regioselective 3-sulfenylation of indoles: Via thiouronium salt formation
Devi, Namita,Sarma, Kuladip,Rahaman, Rajjakfur,Barman, Pranjit
, p. 4583 - 4595 (2018/04/03)
A series of Ni(ii), Cu(ii), Co(ii), and Pd(ii) complexes have been synthesized with a chelating Schiff base ligand coordinated to a metal center with ONS donor atoms. The ligand and complexes are characterized by elemental analysis and spectroscopic techniques like FT-IR, 1H-NMR, and UV-Visible spectroscopy. The single crystal structure of the Pd(ii) complex is obtained by X-ray diffraction analysis and exhibits slightly distorted square planar geometry. The structure is optimized by DFT, TD-DFT calculation to elaborate the electronic structure and NBO for the charge distribution analysis of the Pd(ii) complex. The synthesized Pd(ii) and Ni(ii) complexes as catalysts have been investigated in the C-S cross-coupling of indoles and active methylenes. The metal propelled regioselective transformation afforded 3-sulfenylated indoles while β-diketones favored deacylated monosulfenyl ketones in an excellent yield via thiouronium salt formation. The Pd(ii) complex displays slightly better reactivity whereas the Ni(ii) complex is cost-efficient. The method is fast, easy to handle and cost effective in terms of high reactivity of catalysts, use of non-toxic solvents, and cheaper aryl halides and thiourea replace conventional sulfur sources, providing a practical access to organic transformations.
Enzyme-catalyzed transfer of a ketone group from an S-adenosylmethionine analogue: A tool for the functional analysis of methyltransferases
Lee, Bobby W. K.,Sun, He G.,Zang, Tianzhu,Ju-Kim, Byung,Alfaro, Joshua F.,Zhou, Zhaohui Sunny
supporting information; experimental part, p. 3642 - 3643 (2010/05/15)
"Chemical equation presented" S-Adenosylmethionine (AdoMet or SAM)-dependent methyltransferases belong to a large and diverse family of group-transfer enzymes that perform vital biological functions on a host of substrates. Despite the progress in genomics, structural proteomics, and computational biology, functional annotation of methyltransferases remains a challenge. Herein, we report the synthesis and activity of a new AdoMet analogue functionalized with a ketone group. Using catechol O-methyltransferase (COMT, EC 2.1.1.6) and thiopurine S-methyltransferase (TPMT, EC 2.1.1.67) as model enzymes, this robust and readily accessible analogue displays kinetic parameters that are comparable to AdoMet and exhibits multiple turnovers with enzyme. More importantly, this AdoMet surrogate displays the same substrate specificity as the natural methyl donor. Incorporation of the ketone group allows for subsequent modification via bio-orthogonal labeling strategies and sensitive detection of the tagged ketone prod cts. Hence, this AdoMet analogue expands the toolbox available to interrogate the biochemical functions of methyltransferases.
New hypoxia-selective cytotoxines derived from quinoxaline 1,4-dioxides
Monge,Palop,Gonzalez,Martinez-Crespo,Lopez De Cerain,Sainz,Narro,Barker,Hamilton
, p. 1213 - 1217 (2007/10/02)
A new series of quinoxaline 1,4-dioxides, structurally related to the benzotriazine tirapazamine 1 have been prepared starting from 5,6-dichlorobenzofuroxane 2. The Beirut reaction between 2 and alkyl or aryl thiopropanones afforded the 2-methyl-3-alkyl(a
