Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• functional versatility [44], and many of these resulting metal complexes are catalytically active [45][46][47]. These synthetic metalloporphyrins take inspiration from biological systems, such as hemes (iron complexes), chlorophylls (magnesium complexes), and vitamin B12 (cobalt complex). Contrary to

Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384

• Marwa Elsbaey,
• Naoya Oku,
• Mohamed S. A. Abdel-Mottaleb and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174

• (porphyrins) including heme, chlorophyll, and vitamin B12 [1][2] (Figure S54 in Supporting Information File 1). Porphobilinogen, the fundamental biological precursor of tetrapyrroles, is biosynthesized via asymmetric condensation of two δ-aminolevulinic acid molecules [2][3]. From another aspect

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• ., vitamin B12, chlorophyll, metalloproteins, cyclic peptides, etc). PAMs themselves and their metal complexes exhibit various useful properties [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], particularly, they possess a wide range of biological activities and are used as contrast

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• pharmaceutical agents containing the arylamine moiety as an integral part of the structural framework includes molecule such as retigabine (I) [5], an anticonvulsant used as an adjunctive agent in the treatment of partial seizures, folic acid (II) [6], a type of vitamin B12 displaying an important role in

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• , vitamin B12, porphyrins, chlorins, and bacteriochlorins also contain pyrroles rings (Figure 1). For the synthesis of pyrrole derivatives, many classic methods have been used, including Knorr pyrrole synthesis [29][30], Paal–Knorr synthesis [31][32][33], Hantzsch pyrrole synthesis [34][35][36], Clauson

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• atom to olefins produces a higher substituted carbon radical (Markovnikov addition), making MHAT methodologies especially useful for quaternary carbon center synthesis. One of the first examples of MHAT use in quaternary carbon center construction was the use of vitamin B12 (cobalamin) [70] as a

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

• Ramazan Koçak and
• Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

• ], and self-assembled supramolecular architectures [48]. On the other hand, many natural compounds that contain a pyrrole core, such as bilirubin, hemoglobin, chlorophyll a, and vitamin B12, are very important for life. In addition to being common in natural products and biological systems, the active

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• chloroperoxidase catalyst. H2O2 generated in situ from the cathodic reduction of oxygen was proposed to be responsible for the enzyme-mediated thiol ether oxidation (Scheme 47) [82]. Vitamin B12-dependent enzymes are an exciting representative in the family of chiral inductors for electroorganic chemistry. These

• enzymes involve cobalt in the catalytically active center. In his article, Prof. Hisaeda reviewed vitamin B12-mediated electrochemical reactions in organic solvents in detail [83]. A number of pioneering results have been published in this area by leading electroorganic chemists [84][85][86]. In 1994 and

• 1995, Murakami and his group published two sequential reports on the controlled potential electrolysis of racemic 147 catalyzed by a number of hydrophobic vitamin B12 enzymes 148 to afford hydrogen-substituted product 149 with good enantioselectivity (Scheme 48) [87][88]. Chiral auxiliary approach In

Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF₃SO₃H. NMR and DFT studies of dicationic electrophilic species

• Dmitry S. Ryabukhin,
• Alexey N. Turdakov,
• Natalia S. Soldatova,
• Mikhail O. Kompanets,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191

• common motif present in some components of human organisms, histidine, vitamin B12, purines, histamine, biotin, and in natural compounds such as lepidiline A and B [6]. Over the years of active research, benzimidazole derivatives have been involved in medicinal chemistry covering a wide range of

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

• -enzymatic conditions offers good understanding of their elaborate reaction mechanisms. Furthermore, bio-inspiration offers a new approach to catalytic design for green and eco-friendly molecular transformations. As part of a study based on vitamin B12 derivatives including heptamethyl cobyrinate perchlorate

• 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

• cobalamin with an upper ligand is termed vitamin B12 (a cyanide group), methylcobalamin (a methyl group), and adenosylcobalamin (an adenosyl group), respectively. The oxidation state of cobalt ions in B12 ranges from +1 to +3. Each oxidation state of cobalamins exhibits quite different ligand-accepting

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• postdoctoral fellowship, I spent just under two years with Sir Alan Battersby at the University of Cambridge where we completed the total synthesis of sirohydrochlorin, an intermediate in the biosynthesis of vitamin B12. Then in July 1985, it was off to the University of Illinois at Urbana-Champaign. Molecular

Bright molecules for sensing, computing and imaging: a tale of two once-troubled cities

• A. Prasanna de Silva

Beilstein J. Org. Chem. 2015, 11, 2774–2784, doi:10.3762/bjoc.11.298

• , Vincent Arkley. He not only enthralled us with personal stories of vitamin B12 synthesis, but was also instrumental in opening a channel to Ph.D. study at the Department of Chemistry at Queen’s University Belfast. His former protégé at Glaxo, Ron Grigg, had risen to be the Chair of Organic Chemistry at

An experimental and theoretical NMR study of NH-benzimidazoles in solution and in the solid state: proton transfer and tautomerism

• Carla I. Nieto,
• Pilar Cabildo,
• M. Ángeles García,
• Rosa M. Claramunt,
• Ibon Alkorta and
• José Elguero

Beilstein J. Org. Chem. 2014, 10, 1620–1629, doi:10.3762/bjoc.10.168

• relevant drugs (fungicides, anthelmintics, antiulcerative, antiviral,…) [2][3] are also part of some natural products (the most prominent benzimidazole compound in nature is N-ribosyl-5,6-dimethylbenzimidazole, which serves as an axial ligand for cobalt in vitamin B12) and have interesting ferroelectric

The myxocoumarins A and B from Stigmatella aurantiaca strain MYX-030

• Tobias A. M. Gulder,
• Snežana Neff,
• Traugott Schüz,
• Tammo Winkler,
• René Gees and
• Bettina Böhlendorf

Beilstein J. Org. Chem. 2013, 9, 2579–2585, doi:10.3762/bjoc.9.293

• panthothenic acid, 1 g riboflavin, 2.3 g nicotinic acid, 1.2 g pyridoxine·HCl, 0.1 g vitamin B12 for 1 L solution) for 1 L H2O, pH 7.4) supplemented with 10% XAD-16 for continued product absorption during fermentation. Cells and XAD-16 were separated from the culture broth by filtration and subsequently

The Eschenmoser coupling reaction under continuous-flow conditions

• Sukhdeep Singh,
• J. Michael Köhler,
• Andreas Schober and
• G. Alexander Groß

Beilstein J. Org. Chem. 2011, 7, 1164–1172, doi:10.3762/bjoc.7.135

• became prominent later on when it was applied to the total synthesis of vitamin B12 by Eschenmoser [4]. Since these early days the Eschenmoser coupling has been applied many times as a useful reaction step in a variety of synthesis strategies. Different natural products, such as diplodialid macrolactone

• - [5], sedamine alkaloid- [6], sparteine- [7], mersicarpine- [8], batzelladine- [9], fuligocandin- [10] and vitamin B12-derivatives [11] were prepared with the aid of sulfide contraction steps. Pharmaceutically important substances, such as methylphenidat [12] or the marine neurotoxin hemibrevetoxin

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• synthesis of Vitamin B12 by the groups of Woodward and Eschenmoser [130], this synthesis utilized a powerful methodology developed during this period to make vinylogous amides [131][132]. Pyrrolidinethione 176 was reacted with the dibromoester 177 to give the Z isomer of the vinylogous carbamate 178 (Scheme