Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• first palladium-catalyzed arylation of thiols was reported by Migita and co-workers in 1980 [5], and soon after Cristau and co-workers developed a nickel-catalyzed route for C–S cross-coupling reactions [6]. Other metals such as copper [7], cobalt [8], iron [9], rhodium [10], manganese [11], indium [12

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• heating, ultrasonication and solvent-free conditions alleviated the drawbacks to a major extent [56][57][58][59][60][61]. One such useful strategy include manganese dioxide (MnO2)-mediated oxidative aromatization of 1,4-DHP 45 to afford substituted pyridine derivatives 46 under microwave conditions

• (Scheme 13) [62]. This approach drastically reduces the reaction time to ≈1 minute and provided the desired products in excellent yields (Scheme 13). In another example Peng et al. have demonstrated the use of manganese oxide (MnO2) as an oxidant in the synthesis of 2-arylquinazolines from its

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• from water-dissolved salts. These are shown in Table 2. For example, manganese carbonates (rhodochrosite) and zinc carbonate (smithsonite) were examined. Both adsorbed comparable amounts of RNA to their surfaces in the mineral specimens that were examined, 11% and 5% respectively. Comparable amounts of

• contaminants [28], aragonite is not formed. We easily reproduced this general result, establishing the structure of the precipitated phases that we obtained by both staining with Feigl’s stain (silver sulfate and manganese sulfate) [29] and by powder X-ray diffraction. To complete our analysis of the CaCO3

• clean tubes and radioactive counts in each slide were read at the scintillation counter with the Cherenkov method. Feigl’s staining and X-ray powder diffraction Feigl’s stain [29] is a solution of silver and manganese sulfates. The stain colors orthorhombic and hexagonal carbonates black, but does not

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• an elegant investigation on the model transesterification of ethyl acetate with methanol [9]. The production of biodiesel blends is another sector in which the catalytic transesterification is extensively used. In particular, heterogeneous catalysts including calcium, manganese and zinc oxides as

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• composites obtained showed smooth magnetic hysteresis loops [91]. SWCNT edge activation can be carried out via co-grinding with β- or γ-CDs [92]. Although chemical bonds are also broken in this case, this preparation is closer to the BM assisted preparation of CD complexes in many ways. Nanosized manganese

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• ], manganese- [19][20][21], iron- [23][24], copper- [22][31], rhenium- [26], and rhodium- [27] based reagents. The recent resurgence of interest in the nitroso–ene reaction builds on earlier work by Sharpless, Nicolas, Jørgensen and others. Sharpless reported allylic amination of 2-methyl-2-hexene with N-(p

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• chloride, chloroform or methanol [12] thus MRI applications of Gd-porphyrins are difficult to envisage. Manganese. The design of gadolinium complex did not fully eliminate the risk of in vivo release and accumulation which is a common problem implicated in nephrogenic systemic fibrosis. A possible solution

• is to replace Gd(III) with a more biocompatible metal species, ideally displaying higher relaxivity at high fields. Manganese is a promising candidate with limited toxicity at low concentrations. Up to now and so far to our knowledge, no Mn–DOTA/NOTA complexes have found application as contrast

• agents for MRI. Indeed, manganese complexes of DOTA/NOTA macrocycles are thermodynamically less stable than other transition metal ions or Gd3+ analogues [13]. Over the years and to overcome this problem, a variety of Mn(III) porphyrins have been prepared and investigated for their potential use as MRI

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• o-trifluoroacetamidocinnamaldehyde dimethylhydrazone playing the role of the diene. This medium was refluxed in toluene for 12 h and the product was oxidized with manganese oxide to give two intermediates. The latter were separately subjected to cyclization and deprotection reactions in alkaline

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• metals (such as chromium and manganese) [20][21][22]. Many SCPC oxidations of aromatics have been reported, but of these it is perhaps the oxidation of benzene to phenol that is the most industrially significant [23][24]. Unfortunately, product selectivity is poor because the phenol itself undergoes

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• -immobilized manganese phthalocyanine/H2O2aq [166], a Ni(II) complex/H2O2aq [167], and ZnBr2/H2O2 [168]. The oxidative C–O coupling of aromatic aldehydes 181 with cycloalkanes 182 was accomplished in the presence of the Cu(OAc)2/t-BuOOH system to prepare products 183. This reaction is unusual in that it

• , such as copper and manganese salts, were less often employed for this purpose. 3.1 Oxidative systems based on iodine compounds Iodine(III) organic compounds, including those generated in situ from aryl iodides and peracids (for example, m-chloroperbenzoic acid (MCPBA) and peracetic acid) are most

• . This pathway is confirmed by the fact that, in the presence of Bu4NI, tert-butyl per(1-naphthylate) gives products 203 in the reaction with propiophenone. 3.2 Oxidative systems based on transition metal compounds In addition to iodine compounds, transition metal salts, such as copper and manganese

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• also implemented in the two-component cyclization in the synthesis of phenanthridine derivatives [38]. The starting isocyanide biphenyl (similar to Scheme 8) reacts with the phenyl radical generated from phenylboronic acid and a manganese salt followed by spontaneous cyclisation and aromatisation

Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide

• Richard J. Ingham,
• Claudio Battilocchio,
• Joel M. Hawkins and
• Steven V. Ley

Beilstein J. Org. Chem. 2014, 10, 641–652, doi:10.3762/bjoc.10.56

• which demonstrated the hydration of broad classes of nitriles by passing aqueous–organic solutions through a packed bed of manganese dioxide [21], we have found that heteroaromatic nitriles possessing a β-heteroatom can also be hydrolysed using hydrous zirconia [22][23] in a similar fashion (Figure 3

• packed beds facilitates recycling of the catalyst, providing a further cost advantage. Interestingly, we have now found that no activation of the zirconia is needed (this is the same as for nitrile hydrations with manganese dioxide, but unlike the use of zirconia as a heterogeneous catalyst for Meerwein

A new manganese-mediated, cobalt-catalyzed three-component synthesis of (diarylmethyl)sulfonamides

• Antoine Pignon,
• Erwan Le Gall and
• Thierry Martens

Beilstein J. Org. Chem. 2014, 10, 425–431, doi:10.3762/bjoc.10.39

• related compounds by a new manganese-mediated, cobalt-catalyzed three-component reaction between sulfonamides, carbonyl compounds and organic bromides is described. This organometallic Mannich-like process allows the formation of the coupling products within minutes at room temperature. A possible

• mechanism, emphasizing the crucial role of manganese is proposed. Keywords: carbonyl compounds; cobalt; manganese; multicomponent reaction; organic bromides; sulfonamides; Introduction (Diarylmethyl)amines constitute an important class of pharmacologically active compounds, displaying e.g. antihistaminic

• and versatility of multicomponent procedures, we describe herein a new manganese-mediated, cobalt-catalyzed three-component reaction, which circumvents the above-mentioned limitations by allowing the synthesis of an extended range of (diarylmethyl)sulfonamides (and related compounds) within minutes at

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• -dioxanes Modern approaches to the synthesis of 1,2-dioxanes are based on reactions with singlet oxygen, the oxidative coupling of carbonyl compounds and alkenes in the presence of manganese and cerium salts, the co-oxidation of alkenes and thiols with oxygen, the Isayama–Mukaiyama peroxidation, the

• -dioxan-3-ol (202) and 6-(prop-1-en-2-yl)-1,2-dioxane-3-imine (204), containing the hydroxy and imine groups, respectively (Scheme 56) [304]. 3.2. Oxidative coupling of carbonyl compounds and alkenes in the presence of manganese or cerium salts The synthesis of 1,2-dioxanes 207 is based on the addition of

• alkene 205 and oxygen to carbonyl compound 206 via the intermediate formation of carbon-centered peroxide radicals. The reaction occurs in the presence of catalytic amounts of manganese or cerium salts, which are involved in a redox cycle. It is assumed that the oxidation of β-dicarbonyl compounds

Biosynthesis of rare hexoses using microorganisms and related enzymes

• Zijie Li,
• Yahui Gao,
• Hideki Nakanishi,
• Xiaodong Gao and
• Li Cai

Beilstein J. Org. Chem. 2013, 9, 2434–2445, doi:10.3762/bjoc.9.281

• biocatalysts for industrial-scale applications. The active site in D-psicose 3-epimerase (DPEase) in the presence of D-fructose, showing the metal coordinating site and the substrate-binding site. The purple ball indicates the manganese(II) ion coordinating with key amino acid residues (Glu150, Asp183, His209

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

Hypervalent iodine/TEMPO-mediated oxidation in flow systems: a fast and efficient protocol for alcohol oxidation

• Nida Ambreen,
• Ravi Kumar and
• Thomas Wirth

Beilstein J. Org. Chem. 2013, 9, 1437–1442, doi:10.3762/bjoc.9.162

• ; Introduction Oxidation of alcohols to carbonyl compounds plays an important role in organic chemistry. The transformation is traditionally achieved by using chromium-based reagents such as the Collins reagent, activated manganese dioxide, or procedures known as the Swern [1], Pfitzner–Moffatt [2] or Parikh

Intramolecular carbonickelation of alkenes

• Rudy Lhermet,
• Muriel Durandetti and
• Jacques Maddaluno

Beilstein J. Org. Chem. 2013, 9, 710–716, doi:10.3762/bjoc.9.81

• method are the use of an easily prepared Ni(II)bipy complex in combination with manganese dust as a reducing agent, which is not air sensitive, is compatible with fragile functions, and can be used in a catalytic amount. We showed that this nickel catalysis applies to cross-coupling reactions

• for the carbonickelation of triple bonds [19], we exposed 1a–c to a mixture containing 0.2 equiv of NiBr2bipy and 2 equiv of finely grown manganese in DMF containing trace amounts of trifluoroacetic acid at 50 °C (Table 1). Disappointingly, using 1a the major new product recovered was the dimer 4a

• intramolecular carbonickelation of alkenes To a solution of aryliodide (0.5–1 mmol, 1 equiv) in anhydrous DMF (5 mL) under argon atmosphere at 50 °C is added manganese (2 equiv) followed by NiBr2bipy (0.2 equiv) then rapidly TFA (20 μL). The medium is vigorously stirred at 50 °C, and disappearance of the

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• mersicarpine (60), is another illustration [31]. The aromatisation process in this example was incomplete under the usual conditions and required further treatment with manganese dioxide. The possibility of associating the radical chemistry of xanthates with various ionic reactions represents another powerful

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

• further examples of iron(II) SCO compounds have been published [7][8][9][10][11][12][13][16][17][18][19][20][21][22][23][24][25][26][27][28], and other coordination compounds of 3d transition elements such as cobalt(II) [29][30], and to a much lesser extent cobalt(III), chromium(II), manganese(II

• ), manganese(III), and nickel were found to exhibit thermal ST phenomena [31][32][33]. But practically no example of thermal ST with coordination compounds of the 4d and 5d transition metal series has been reported up to now, which is well understood on the basis of ligand field theory [34][35]. The purpose of

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• ). Methyl-, ethyl-, and phenylmagnesium reagents could be employed for the reaction. Aside from the examples shown in Scheme 5 and Scheme 6, alkynes that possess a directing group usually undergo syn-addition. Oshima reported manganese-catalyzed regio- and stereoselective carbomagnesiation of homopropargyl

• product (58% yield) from 44 kg of 1-phenyl-1-butyne. Oshima reported manganese-catalyzed phenylmagnesiation of a wide range of arylacetylenes (Table 4) [102]. Notably, directing groups, such as ortho-methoxy or ortho-amino groups, facilitated the reaction (Table 4, entries 2 and 3 versus entry 4

• ][139][140][141][142][143]. Manganese-catalyzed regioselective allylmetalation of allenes was reported (Scheme 53) [144]. The regioselectivity of the manganese-catalyzed addition reaction was opposite to that of the rhodium-catalyzed reactions, and vinylmagnesium intermediates were formed. Although

Dimerization of a cell-penetrating peptide leads to enhanced cellular uptake and drug delivery

• Jan Hoyer,
• Ulrich Schatzschneider,
• Michaela Schulz-Siegmund and
• Ines Neundorf

Beilstein J. Org. Chem. 2012, 8, 1788–1797, doi:10.3762/bjoc.8.204

• or hydrophilicity. Recently, we reported on the identification of a novel CPP, sC18, which is derived from the C-terminus of the 18 kDa cationic antimicrobial protein. Furthermore, we demonstrated successful application of sC18 for the delivery of functionalized cyclopentadienyl manganese tricarbonyl

• -homing agent, which accumulates in hypoxic tissue [10]. Furthermore, we reported on the delivery of functionalized cyclopentadienyl manganese tricarbonyl (cymantrene) complexes with the help of sC18, which lead to significant induction of cytotoxicity in tumor cells [11][12][13], which was even more

An easily accessible sulfated saccharide mimetic inhibits in vitro human tumor cell adhesion and angiogenesis of vascular endothelial cells

• Grazia Marano,
• Claas Gronewold,
• Martin Frank,
• Anette Merling,
• Christian Kliem,
• Sandra Sauer,
• Manfred Wiessler,
• Eva Frei and
• Reinhard Schwartz-Albiez

Beilstein J. Org. Chem. 2012, 8, 787–803, doi:10.3762/bjoc.8.89

• , revealed specific docking of GSF to the same binding site as the natural peptidic ligands of this integrin. The sulfate in the molecule coordinated with one manganese ion in the binding site. These studies show that this chemically easily accessible molecule GSF, synthesized in three steps from 3,4-bis

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester

• Sarah L. Harding,
• Sebastian M. Marcuccio and
• G. Paul Savage

Beilstein J. Org. Chem. 2012, 8, 606–612, doi:10.3762/bjoc.8.67

• halogenation–dehydrohalogenation process is most common, several methods involving direct oxidative dehydrogenation of aldoximes have been reported, including the use of lead tetraacetate [22][23], mercury(II) acetate [24], hypervalent iodine [25][26], and manganese(IV) oxide [27]. We were interested in