A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage

• Kesari Lakshmi Manasa,
• Yellaiah Tangella,
• Namballa Hari Krishna and
• Mallika Alvala

Beilstein J. Org. Chem. 2019, 15, 1864–1871, doi:10.3762/bjoc.15.182

• 10.3762/bjoc.15.182 Abstract An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage

• of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High

• chemistry. The occurrence of an amide and/or ester bond is widely realized in organic molecules, proteins, natural products, pharmaceuticals, polymers and agrochemicals [1][2][3][4][5]. The conventional synthesis of amides involves the reaction of carboxylic acids or their derivatives such as acyl halides

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• . The Pd-catalyzed Sonogashira reaction has successfully constructed arylated internal alkynes that are important intermediates in organic synthesis, molecular electronics and polymers [56]. C–N bond forming reactions between aryl halides and amines/amides/sulfonamides have been extensively studied in

Synthesis of ([1,2,4]triazolo[4,3-a]pyridin-3-ylmethyl)phosphonates and their benzo derivatives via 5-exo-dig cyclization

• Aleksandr S. Krylov,
• Artem A. Petrosian,
• Julia L. Piterskaya,
• Nataly I. Svintsitskaya and
• Albina V. Dogadina

Beilstein J. Org. Chem. 2019, 15, 1563–1568, doi:10.3762/bjoc.15.159

• amidines and amides was observed [4]. Moreover, the formazan-type products, the formation of which was observed in reactions of chloroethynylphosphonates with arylhydrazines, were not detected [16]. The structures of [1,2,4]triazolo[4,3-a]pyridines 3–8 were confirmed by IR, 1Н, 13C and 31P NMR spectroscopy

Transient and intermediate carbocations in ruthenium tetroxide oxidation of saturated rings

• Manuel Pedrón,
• Laura Legnani,
• Maria-Assunta Chiacchio,
• Pierluigi Caramella,
• Tomás Tejero and
• Pedro Merino

Beilstein J. Org. Chem. 2019, 15, 1552–1562, doi:10.3762/bjoc.15.158

• with ruthenium tetroxide allows to introduce an oxygenated functionality (alcohol or carbonyl) into a saturated carbon skeleton [7]. Moreover, if oxygen or nitrogen atoms are present, the reaction leads to the formation of esters [8][9] or amides [10][11], respectively (Scheme 1). The reaction is

Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• able to measure its 1H NMR spectrum in D2O at elevated temperature (80 °C, see Supporting Information File 1). Taking into account the stability of the P–N bond against hydrolysis, we conducted reactions of the cations A, B, and F–H with morpholine (Scheme 3). Amides 6a,b were isolated as products of

• these reactions in excellent yields. The plausible reaction mechanism includes at the first stage nucleophilic attack of morpholine onto the phosphorus cationic center that gives cation I, which is transformed into species J. Hydrolysis of the latter leads to cation K and then finally to amides 6a,b. We

• carried out a large-scale one-pot solvent-free synthesis of amides 6a,b starting from propargyl alcohols 7a,b at room temperature (Scheme 4). At the first step, alcohols 7a,b in the reaction with PCl3 were transformed into the corresponding allenes 1a,h. Then, the addition of Brønsted acid (TfOH or H2SO4

Synthesis of pyrrolo[1,2-a]quinolines by formal 1,3-dipolar cycloaddition reactions of quinolinium salts

• Anthony Choi,
• Rebecca M. Morley and
• Iain Coldham

Beilstein J. Org. Chem. 2019, 15, 1480–1484, doi:10.3762/bjoc.15.149

• ester 4 and amide 5 with electron-deficient alkenes 6. Reactions of ester 4 and amide 5 with N-methylmaleimide. Reduction and oxidation of adducts 9 and 10. Formation of amides 15a and 15b and Suzuki–Miyaura coupling to yield 16. Supporting Information Supporting Information File 322: Experimental

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• significantly distorted to accommodate AuCl4− in the cavity of 1. In contrast, AuCl4− cannot be encapsulated in the cavity of 2 (Figure 5b). Hydrogen bonds between the pyridine moiety and adjacent amides significantly shrink the cavity [43], and thus the cavity cannot be distorted to fit AuCl4−. Otherwise, a

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• acid derivative as one of the substrates of the reaction, together with an amine and a third reagent that provides the carbon atom needed to complete the cyclic moiety. Thus, Shi et al. [76] reacted benzoic acid derivatives 1, amides 2 and DMSO (3) in the presence of DDQ as oxidant and without any

• three-component reaction between aryl iodides, incorporating a Michael acceptor 105, amines and amides 2 and carbon monoxide (23) (Scheme 30) [108]. It is remarkable that not only aromatic but also aliphatic amines and even amides and sulfonamides can be used as the nitrogen-containing substrate. With

• . Nevertheless, most of the known multicomponent methods for the preparation of 2-oxindoles are based on the use of N-aryl amides as the main partner of the reagent pool. Wu et al. reacted N-(2-iodoaryl)acrylamides 113, DABCO·(SO2)2 (69, also known as DABSO) as a surrogate of sulfur dioxide and hydrazine 114 in

An anomalous addition of chlorosulfonyl isocyanate to a carbonyl group: the synthesis of ((3aS,7aR,E)-2-ethyl-3-oxo-2,3,3a,4,7,7a-hexahydro-1H-isoindol-1-ylidene)sulfamoyl chloride

• Aytekin Köse,
• Aslı Ünal,
• Ertan Şahin,
• Uğur Bozkaya and
• Yunus Kara

Beilstein J. Org. Chem. 2019, 15, 931–936, doi:10.3762/bjoc.15.89

• reacts with unsaturated systems to yield either N-chlorosulfonyl-β-lactams 3 or unsaturated N-chlorosulfonyl amides 4 (Scheme 1). β-Lactams 3 generally predominate and in many cases are the exclusive products and they serve as key substances in a variety of chemical transformations. When chlorosulfonyl

• amides 4 are produced, they may be converted to other compounds. Graf [1] proposed that the reaction of CSI with unsaturated systems proceeds via the direct formation of dipolar intermediate 5 which may undergo a ring closure to form 3 or a hydrogen transfer to afford 4 (Figure 1). A wide variety of

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• the amides 47 (Figure 26). The development of sustainable methods for the activation of less-reactive undirected C(sp3)–H bonds is challenging however, highly desired in organic synthesis. Mal and co-workers also demonstrated that acidic C(sp3)–hydrogen bonds within a molecule could be used to control

Synthesis of a novel category of pseudo-peptides using an Ugi three-component reaction of levulinic acid as bifunctional substrate, amines, and amino acid-based isocyanides

• Maryam Khalesi,
• Azim Ziyaei Halimehjani and
• Jürgen Martens

Beilstein J. Org. Chem. 2019, 15, 852–857, doi:10.3762/bjoc.15.82

• transfer from oxygen to nitrogen (Mumm rearrangement) in D which completes the Ugi reaction accompanied by formation of the corresponding bis-amides. The structure of products was confirmed by IR, 1H and 13C NMR, CHN and HRMS analyses and by X-ray crystallography for 4a. The IR spectra of the derivatives

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• thanks to their tolerance against various functional groups such as amides, alcohols and carboxylic acids. However, one major hurdle for olefin metathesis in chemical biology remains the necessity to perform catalysis under mild conditions in buffered aqueous media. The aqueous ROMP introduced by Grubbs

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• corresponding N-alkyl-nicotinamides. A more reactive 2,3,5-tri-O-acetyl-β-phenyl nicotinate riboside 20 was therefore generated. To limit transesterification and favor amidation, trifluoroethanol was used as solvent instead of methanol, and as a result, amides 21 were prepared in good yields (Scheme 11). In

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• ][36]. Diazoacetamides, in particular, diazo Weireb amides were tested in our catalytic system because the resulting cyclopropane products can be easily converted into the corresponding aldehydes, ketones, and alcohols [37][38][39][40][41][42][43][44][45][46][47][48]. Results and Discussion Asymmetric

• ). These results encouraged us to explore the asymmetric intramolecular cyclopropanation of diazo Weinreb amides in a biphasic medium. Asymmetric cyclopropanation using diazo Weinreb amide with Ru(II)-Amm-Pheox Ru(II)-Pheox (cat. 1) was slightly soluble in water, and afforded only a 53% yield of product in

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• [(2S,4S)-3] was found in several plants, e.g., Phlox decussata [29] and other Phlox species [30], as well as in Linaria vulgaris [31]. It has also been discovered in mammalian cells as an intermediate in the degradation of hydroxyproline [32][33]. Its various amides have been identified in numerous

Selective ring-opening metathesis polymerization (ROMP) of cyclobutenes. Unsymmetrical ladderphane containing polycyclobutene and polynorbornene strands

• Yuan-Zhen Ke,
• Shou-Ling Huang,
• Guoqiao Lai and
• Tien-Yau Luh

Beilstein J. Org. Chem. 2019, 15, 44–51, doi:10.3762/bjoc.15.4

• linker is because the ester group could be selectively hydrolyzed in the presence of amides. This selectivity will be helpful for the structural elucidation of polymer 8. Thus, 10b was allowed to react with 11 to afford amide-alcohol 12 in 79% yield. Esterification of 12 with 13b furnished 70% yield of

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• function of 16, followed by its coupling with glycine or phenylalanine ethyl esters (respectively 20a and 20b) using 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (TBTU) as a coupling agent to give the corresponding amides 21a,b. The isoxazole ring of these compounds was then

Synthesis of functionalised β-keto amides by aminoacylation/domino fragmentation of β-enamino amides

• Pavel Yanev and
• Plamen Angelov

Beilstein J. Org. Chem. 2018, 14, 2602–2606, doi:10.3762/bjoc.14.238

• Pavel Yanev Plamen Angelov Department of Organic Chemistry, University of Plovdiv Paisii Hilendarski, 24 Tsar Asen Str., 4000 Plovdiv, Bulgaria 10.3762/bjoc.14.238 Abstract Ethylenediamine-derived β-enamino amides are used as equivalents of amide enolate synthons in C-acylation reactions with N

• -protected amino acids. Domino fragmentation of the obtained intermediates leads to functionalised β-keto amides, bearing a protected amino group in their side chain. Keywords: amino acids; C-acylation; domino reaction; enamines; enaminones; keto amides; retro-Mannich; Introduction The acylation of amide

• enolates is one of the main synthetic approaches towards β-keto amides and has found numerous applications [1][2][3][4][5][6][7][8][9]. However, while the generation of tertiary amide enolates is straightforward, this is not the case with secondary and primary amides. The NH acidity of the latter compounds

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

• terms of both catalytic activity and visible-light harvesting. In relation to the reactivity of 1 with DDT, interesting reactions of trichlorinated organic compounds have recently been investigated [100][114]. The B12-TiO2 hybrid catalyst converted trichlorinated organic compounds into esters and amides

• of the esters and amides. The aerobic electrolysis of trichlorinated organic compounds was also mediated by 1 to yield esters and amides [114]. These reactions are important in terms of fine chemical production from trichlorinated organic compounds through easy operations (i.e., in air at room

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

• Nadia Gruber,
• Jimena E. Díaz and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2018, 14, 2510–2519, doi:10.3762/bjoc.14.227

• primary and secondary amines [98]. On the other hand, it is known that N-unsubstituted amides react with PPSE affording nitriles [99]. In this context, the cyclodehydration of N-monosubstituted amides 3 could in principle involve an initial PPSE-mediated elimination generating a reactive nitrilium ion in

Hydroarylations by cobalt-catalyzed C–H activation

• Rajagopal Santhoshkumar and
• Chien-Hong Cheng

Beilstein J. Org. Chem. 2018, 14, 2266–2288, doi:10.3762/bjoc.14.202

• functionalization. Of these reactions, alkylation, alkenation, amidation, and cyclization of arenes with the relevant coupling partners are an economical and straightforward approach for the synthesis of diverse alkyls, alkenes, amides and cyclic compounds. A simple addition of a “inert” C–H bond to multiple bonds

• As alkynes efficiently participated in low-valent cobalt-catalyzed hydroarylations (section 1.1), Nakamura and co-workers developed an analogous hydroarylation reaction of alkenes [39]. Thus, the reaction of amides 23 with alkenes in the presence of 10 mol % Co(acac)3, 1.5 equiv CyMgCl, and 6.0 equiv

• , Whiteoak’s group reported a cobalt-catalyzed hydroarylation of terminal alkenes with amides 39 [78]. The reaction of vinyl ketones with amides provided alkylated product 40, whereas acrolein resulted in biologically useful azepinones in good yields (Scheme 26b). N-Pyrimidylindole is a highly reactive arene

A general and atom-efficient continuous-flow approach to prepare amines, amides and imines via reactive N-chloramines

• Katherine E. Jolley,
• Michael R. Chapman and
• A. John Blacker

Beilstein J. Org. Chem. 2018, 14, 2220–2228, doi:10.3762/bjoc.14.196

• afford amides. Primary and secondary imines were produced under continuous conditions from the reaction of N-chloramines with base, with one example subsequently reduced under asymmetric conditions to produce a chiral amine in 94% ee. Keywords: continuous flow; CSTR; N-chloramine; synthetic methods

• reagents can be used as electrophilic or radical amination agents in a wide range of reactions [14]. In the present study, we opted to evaluate the addition of N-alkyl-N-chloramines with (a) alkenes to produce amines, (b) aldehydes to give amides, (c) reaction with a base to afford imines. Several alkenes

• ][33]. Improved methods for the formation of amides remain an important goal for the pharma industry. In this regard, the reaction of N-chloramine with aldehydes, t-BuO2H and iron or copper catalysts to give secondary and tertiary amides was reported in batch recently [33][34], though safety concerns

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• Peptide-type linkages Medicinal chemists often draw inspiration from nature for the design of their molecules. With the exception of certain natural products, most naturally occurring biologically active molecules contain amides. The formation of the amide functional group is the most utilised reaction in

• medicinal chemistry. This is a reflection of the tendency of synthetic bioactive molecules to exhibit peptidomimetic properties. Though there is a vast number of procedures that generate amide bonds, an interesting approach is taken by Leow, who has demonstrated the synthesis of amides through the oxidative

• environmentally benign process, when compared to traditionally used amide coupling methods where acid activating agents are needed, e.g., HATU or DCC, as the only byproduct is water. Only arylaldehydes can be converted into amides and all but one of the examples of the amines used are secondary cyclic amines

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• illustrated in Scheme 1, the preparation starts from the related anilines 1 which were acylated with 3-bromopropionyl chloride (2) to afford amides 3. Upon basic treatment with t-BuONa, the amides 3 were converted to the cyclized β-propiolactams 4. In the presence of triflic acid, the Fries rearrangement

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• result was obtained by replacing PhI(OAc)2 with PhI. In addition, phosphates were suitable nucleophiles in this reaction, giving phosphoryloxylactones in good yields [44]. A similar catalytic cyclization of unsaturated amides leading to oxazolines and dihydrooxazines was developed, in which Selectfluor