Synthesis and biological evaluation of 1,2-disubstituted 4-quinolone analogues of Pseudonocardia sp. natural products

• Stephen M. Geddis,
• Teodora Coroama,
• Suzanne Forrest,
• James T. Hodgkinson,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2018, 14, 2680–2688, doi:10.3762/bjoc.14.245

• heterocyclisation with concomitant N–>N’ methyl transfer. With the library of natural products and analogues in hand, our attention turned to their biological activity. It was desired to further explore the growth defects which had been previously noted for natural products 1–4 against E. coli and S. aureus, and so

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• also described, with a focus on radical-involved reactions in terms of organic synthesis. Keywords: dehalogenation; electrolysis; green chemistry; heptamethyl cobyrinate; methyl transfer; 1,2-migration; photosensitizer; vitamin B12; Review 1. Introduction 1-1. Redox and coordination chemistry of B12

• -light-driven through the use of [Ru(bpy)3]2+ as an alternative to reductases. This serves as a simplified analogy for the B12 enzyme-involving system (Figure 2a). The B12-Ru@MOF is the best system for the functional simulation of MMCM among our B12 artificial enzymatic systems. 3. Methyl transfer

• reactions The B12-dependent methionine synthase catalyzes the methyl transfer reaction as shown in Scheme 6a. In the active center of the enzyme, cob(I)alamin accepts the methyl group from methyltetrahydrofolate (CH3-H4-folate) and the resultant methylcobalamin donates it to homocysteine [65][66

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• cation. Methyl-transfer affords the desired aryl methyl sulfoxide. The scope of this reaction included various electron-rich and poor aryl and heteroaryl diazonium salts. Diverse functional groups, like nitriles, thiocyanates ketones or esters were tolerated. Sulfinic acids and sulfinate salts Formation

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• transition states TI and TII for the transfer of the methyl moiety from AlMe3 to the imino moiety. b) X-ray crystal structure analysis of the methyl transfer product 10k. Base-induced rearrangement of propargylamines bearing electron-withdrawing substituents. Base-catalyzed rearrangement of propargylamines

Synthesis of guanidinium–sulfonimide ion pairs: towards novel ionic liquid crystals

• Martin Butschies,
• Manuel M. Neidhardt,
• Markus Mansueto,
• Sabine Laschat and
• Stefan Tussetschläger

Beilstein J. Org. Chem. 2013, 9, 1093–1101, doi:10.3762/bjoc.9.121

• compared to the corresponding protonated compounds. However, the K+-sulfonimides 6a,b were not used for a direct methyl transfer towards the synthesis of the desired guanidinium–sulfonimide ion pairs in a similar way that the arylsulfonic acid methylesters were previously used as methyl transfer reagents

Catalysis: transition-state molecular recognition?

• Ian H. Williams

Beilstein J. Org. Chem. 2010, 6, 1026–1034, doi:10.3762/bjoc.6.117

• concept. It is shown that reactant binding is intrinsically inhibitory, and that attempts to design catalysts that focus simply upon attractive interactions in a binding site may fail. Free-energy changes along the reaction coordinate for SN2 methyl transfer catalysed by the enzyme catechol-O-methyl

• cases of methyl transfer and of glycoside hydrolysis to illustrate and to update the same theme from a computational point of view. Discussion The transition state is of strategic importance within the field of chemical reactivity. Owing to its location in the region of the highest energy point on the

• an archetypal reaction in organic chemistry and an important process in biochemistry. Catechol-O-methyl transferase (COMT) catalyses methyl transfer from S-adenosylmethionine (SAM) to a catechol (Scheme 1), and this reaction manifests an unusually large inverse secondary kinetic isotope effect as

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• enantioselective trifluoromethylation of β-ketoesters. Fluorinated Johnson’s type reagent In 2008, a novel type of electrophilic trifluoromethylating agent, a trifluoro analog of Johnson’s methyl-transfer reagent 41, was synthesized by Shibata and co-workers. Transfer of the CF3 group from 42 to various substrates