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Search for "N-alkylation" in Full Text gives 98 result(s) in Beilstein Journal of Organic Chemistry.

Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

  • Robin Klintworth,
  • Garreth L. Morgans,
  • Stefania M. Scalzullo,
  • Charles B. de Koning,
  • Willem A. L. van Otterlo and
  • Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

Graphical Abstract
  • 19a. This enaminone-based method for constructing a pyrrole ring is similar to that in our reported routes to lamellarin alkaloids, in which N-alkylation of (Z)-configured 3,4-dihydroisoquinoline-derived enaminones with ethyl bromoacetate under either conventional [49][50] or microwave [51] heating
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Published 13 Oct 2021

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

  • Ryan M. Alam and
  • John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

Graphical Abstract
  • distribution. For example, employing C-7 NO2 or CO2Me substituted indazoles conferred excellent N-2 regioselectivity (≥ 96%). Importantly, we show that this optimized N-alkylation procedure tolerates a wide structural variety of alkylating reagents, including primary alkyl halide and secondary alkyl tosylate
  • electrophiles, while maintaining a high degree of N-1 regioselectivity. Keywords: indazole; N-alkylation; regioselective; sodium hydride; tetrahydrofuran; Introduction Indazole (benzo[c]pyrazole) is an aromatic bicyclic heterocycle and can be viewed as a (bio)isostere of indole [1]. While only a few naturally
  • achieve regioselective indazole N-alkylation have exploited the noted difference in reactivity between the N-1 and N-2 atom of the indazole scaffold [15], as the 1H-indazole tautomer is typically considered to be more thermodynamically stable than the corresponding 2H-tautomer [16]. Using appropriate α
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Published 02 Aug 2021

Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings

  • Ivan P. Mosiagin,
  • Olesya A. Tomashenko,
  • Dar’ya V. Spiridonova,
  • Mikhail S. Novikov,
  • Sergey P. Tunik and
  • Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2021, 17, 1490–1498, doi:10.3762/bjoc.17.105

Graphical Abstract
  • [3,4-c]isoquinolin-4-ium bromide 8. Free-radical cyclization of dihalogeno-substituted salts 9 and 12. N-alkylation of the base 6a. Isomerization of compounds 17a and 18a. N-Alkylation of compounds 18a and 19. Optimization of the reaction conditions for the cyclization of 1a with TTMSS/AIBN in MeCN
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Published 23 Jun 2021

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

  • Joseane A. Mendes,
  • Paulo R. R. Costa,
  • Miguel Yus,
  • Francisco Foubelo and
  • Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Graphical Abstract
  • generated, taking place a diastereoselective nucleophilic dichloromethylation of the imine. The addition took place almost exclusively to the Re face of the imine (RS)-14, which is the less sterically hindered in the most stable s-cis conformation (see Scheme 2). The second intramolecular N-alkylation step
  • ketone derivative 111, which was not isolated. After removal of the sulfinyl group under acidic conditions, and intramolecular N-alkylation upon treatment with sodium bicarbonate, (−)-pelletierine (112) was formed, and easily isolated as its hydrochloride derivative (Scheme 32) [120]. Compound 112 is a
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Published 12 May 2021

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

  • Soumyaranjan Pati,
  • Renata G. Almeida,
  • Eufrânio N. da Silva Júnior and
  • Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

Graphical Abstract
  • leading to poor N1/N2 selectivity, for instance, in the direct N-alkylation of triazoles [21][22][23]. Despite these challenges, a number of N1- and N2-selective alkylation methods have been developed employing transition metal catalysts which include Au-catalysed desulfonylative coupling N-tosyl-1,2,3
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Published 31 Mar 2021

Synthesis of tetrafluorinated piperidines from nitrones via a visible-light-promoted annelation reaction

  • Vyacheslav I. Supranovich,
  • Igor A. Dmitriev and
  • Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 3104–3108, doi:10.3762/bjoc.16.260

Graphical Abstract
  • likely starts from the addition of the fluorinated radical to the C=N bond followed by a conversion of the nitroxyl radical via hydrogen atom transfer [26][27] providing hydroxylamine 4. At the next stage, the intramolecular N-alkylation occurs leading to an N-oxide. This step of nucleophilic
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Published 29 Dec 2020

Ultrasound-assisted Strecker synthesis of novel 2-(hetero)aryl-2-(arylamino)acetonitrile derivatives

  • Emese Gal,
  • Luiza Gaina,
  • Hermina Petkes,
  • Alexandra Pop,
  • Castelia Cristea,
  • Gabriel Barta,
  • Dan Cristian Vodnar and
  • Luminiţa Silaghi-Dumitrescu

Beilstein J. Org. Chem. 2020, 16, 2929–2936, doi:10.3762/bjoc.16.242

Graphical Abstract
  • lipophilic character of the metallocene [11]. However, only a limited number of reports described the application of ultrasonic irradiation for the synthesis of phenothiazine derivatives, and included the N-alkylation of 10H-phenothiazine [12], condensation of phenothiazine carbaldehyde with hydrazino
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Published 30 Nov 2020

Convenient access to pyrrolidin-3-ylphosphonic acids and tetrahydro-2H-pyran-3-ylphosphonates with multiple contiguous stereocenters from nonracemic adducts of a Ni(II)-catalyzed Michael reaction

  • Alexander N. Reznikov,
  • Dmitry S. Nikerov,
  • Anastasiya E. Sibiryakova,
  • Victor B. Rybakov,
  • Evgeniy V. Golovin and
  • Yuri N. Klimochkin

Beilstein J. Org. Chem. 2020, 16, 2073–2079, doi:10.3762/bjoc.16.174

Graphical Abstract
  • presence of Pd/C. However, phosphonate 7 was unstable: already during its isolation, it was partially transformed into compounds 8 and 9. It can be assumed that N-alkylation by the phosphoryl group occurs [47][48][49]. To avoid this undesirable process, the product 7 was formylated before its isolation
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Published 25 Aug 2020

Et3N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

  • Dharmender Singh,
  • Vipin Kumar and
  • Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

Graphical Abstract
  • substituents at C1 (R4), compound 4eA with aromatic substituent exhibited better fluorescence due to extended conjugation. The effect of R2 substituent in these derivatives (4bA, 4dA, 4fA and 4gA) was also investigated and it was found that N-alkylation improved the photophysical properties along with higher
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Published 20 Jul 2020

Pauson–Khand reaction of fluorinated compounds

  • Jorge Escorihuela,
  • Daniel M. Sedgwick,
  • Alberto Llobat,
  • Mercedes Medio-Simón,
  • Pablo Barrio and
  • Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

Graphical Abstract
  • sulfonamides 47, followed by the introduction of the fluoroallyl group via N-alkylation with previously described mesylate 38 provided fluorinated enynes 48 (Scheme 24). The enantioenriched starting materials 48 were then evaluated in the Co-mediated PKR to yield the bicyclic products 49 in moderate to good
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Published 14 Jul 2020

Heterogeneous photocatalysis in flow chemical reactors

  • Christopher G. Thomson,
  • Ai-Lan Lee and
  • Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

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Published 26 Jun 2020

The McKenna reaction – avoiding side reactions in phosphonate deprotection

  • Katarzyna Justyna,
  • Joanna Małolepsza,
  • Damian Kusy,
  • Waldemar Maniukiewicz and
  • Katarzyna M. Błażewska

Beilstein J. Org. Chem. 2020, 16, 1436–1446, doi:10.3762/bjoc.16.119

Graphical Abstract
  • for studying the possibility of an N-alkylation by alkyl bromide, formed during the silylation step. Finally, compound 13 was included to study the possibility of a chlorine for bromine exchange reaction. The phosphonocarboxylates 8 and 9 were used to explore whether the carboxyester group could be
  • water and 1 equiv of TEA. Section 3: N-Alkylation As reported in the original paper [1], the McKenna reaction required up to 2 h at room temperature for simple phosphonates. However, depending on the structure of the phosphonate, longer reaction times are required, and the reaction is commonly carried
  • the gas needed to be gently controlled to avoid BTMS removal from the reaction mixture. We encountered a different situation for compound 12. This substrate underwent N-alkylation under the McKenna reaction conditions only in the presence of Et3N, a commonly used additive for the protection of
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Published 23 Jun 2020

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

  • Qiao Lin,
  • Shiling Zhang and
  • Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

Graphical Abstract
  • Qiao Lin Shiling Zhang Bin Li School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, Guangdong Province, P.R. China 10.3762/bjoc.16.44 Abstract An efficient and simple KOt-Bu-promoted selective ring-opening N-alkylation of 2-methyl-2-oxazoline or 2-(methylthio)-4,5
  • important role to promote this ring-opening N-alkylation, but also acts as an oxygen donor. Keywords: N-alkylation; oxazolines; potassium tert-butoxide; ring opening; thiazolidinones; Introduction 2-Oxazolines are important structural units in pharmaceutical applications and efficient ligands in
  • TMSN3 as the azide source [10] (Scheme 1a). Coates described a Co2(CO)8-catalyzed ring-opening hydroformylation of oxazolines for the synthesis of β-amidoaldehydes [11] (Scheme 1a). However, the ring-opening N-alkylation of 2-oxazolines to produce 2-aminoethyl acetate derivatives under basic conditions
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Published 25 Mar 2020

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

  • Abhijit Paul,
  • Debnath Chatterjee,
  • Srirupa Banerjee and
  • Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

Graphical Abstract
  • -anchored indole-5-carboxylic acid was successful during the homogeneous two-phase alkenylation reaction. Subsequently, during its removal from the support under alkaline conditions, N-alkylation occurred through a Michael addition to the acrylate 2a, followed by the formation of the methyl ester of the 5
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Published 29 Jan 2020

Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos

  • Sergii Afonin,
  • Oleg Babii,
  • Aline Reuter,
  • Volker Middel,
  • Masanari Takamiya,
  • Uwe Strähle,
  • Igor V. Komarov and
  • Anne S. Ulrich

Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6

Graphical Abstract
  • derivatives of 2 [30]. The library contained 29 compounds grouped into several series: with natural amino acid mutations affecting the amphipathicity (series i), with point mutations that modulate polarity and conformational stability of the β-structural elements (series ii), with backbone N-alkylation and
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Published 07 Jan 2020

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

  • Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

Graphical Abstract
  • solubility in aqueous medium and potential RNA-binding properties, the dimethylaminopropyl substituent [19] was introduced to hemi-indigo Z-1c. Two synthetically straightforward approaches of the alkylamino group introduction were considered: (i) N-alkylation of the indoxyl core and (ii) O-alkylation of the
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Published 22 Nov 2019

1,2,3-Triazolium macrocycles in supramolecular chemistry

  • Mastaneh Safarnejad Shad,
  • Pulikkal Veettil Santhini and
  • Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

Graphical Abstract
  • macroring. A second strategy is the macrocyclization of an acyclic precursor containing pre-functionalized triazole by other ring closure methods such as Grubbs metathesis [25] and amidation reactions. The macrocyclization is normally followed by N-alkylation (often methylation) leading to the synthesis of
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Published 12 Sep 2019

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

Graphical Abstract
  • N-alkylation of a pyridine [19][20][21][22][23][24][25][26][27], isoquinoline [26][27][28][29][30][31][32], or related structures [33][34][35], followed by deprotonation. Such ylides are formally azomethine structures assuming reactivity of the aromatic ring as an iminium ion, although the reaction
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Published 03 Jul 2019

A chemically contiguous hapten approach for a heroin–fentanyl vaccine

  • Yoshihiro Natori,
  • Candy S. Hwang,
  • Lucy Lin,
  • Lauren C. Smith,
  • Bin Zhou and
  • Kim D. Janda

Beilstein J. Org. Chem. 2019, 15, 1020–1031, doi:10.3762/bjoc.15.100

Graphical Abstract
  • intermediate, while the fentanyl-like domains of HF-1, HF-2, HF-3, and HF-7 (Figure 2) might be accessed from the same synthesis. Our other consideration was the general strategy for joining the two drug domains to form our chemically contiguous epitope. We envisioned synthesizing HF-1, HF-2, and HF-4 by N
  • -alkylation of the heroin domain via reductive amination. For the remaining drug–haptens, the use of repeated amide bonds naturally led us to employ EDC-mediated coupling to join the heroin and fentanyl domains. For the sake of brevity, detailed synthetic procedures, and structures of all intermediates can be
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Published 03 May 2019

An improved synthesis of adefovir and related analogues

  • David J. Jones,
  • Eileen M. O’Leary and
  • Timothy P. O’Sullivan

Beilstein J. Org. Chem. 2019, 15, 801–810, doi:10.3762/bjoc.15.77

Graphical Abstract
  • the versatility of our approach. Keywords: acyclic nucleoside phosphonate; adefovir; alkylation; antiviral; N-alkylation; purine; Introduction The acyclic nucleoside phosphonate adefovir (1) [1], administered as its dipivoxil prodrug form (2) [2], is used clinically for the treatment of infections
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Published 29 Mar 2019

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

  • Rodrigo Abonia,
  • Luisa F. Gutiérrez,
  • Braulio Insuasty,
  • Jairo Quiroga,
  • Kenneth K. Laali,
  • Chunqing Zhao,
  • Gabriela L. Borosky,
  • Samantha M. Horwitz and
  • Scott D. Bunge

Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60

Graphical Abstract
  • in 80–98% yield by N-alkylation of commercially available N–H indoles 1{1–3} ({1} R = H; {2} R = F and {3} R = OMe), by adopting a procedure similar to that described by Kong et al. [58] (Scheme 3). The quinolone aldehydes 5 were synthesized via 2-chloroquinoline-3-carbaldehydes 4 mediated by a Meth
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Published 12 Mar 2019

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes

  • Krzysztof M. Zwoliński and
  • Julita Eilmes

Beilstein J. Org. Chem. 2019, 15, 617–622, doi:10.3762/bjoc.15.57

Graphical Abstract
  • , were synthesized in satisfactory 26–28% isolated yields. Direct N-alkylation of 1,4,10-trioxa-7,13-diazacyclopentadecane by symmetric DBTAA derivatives bearing bromoalkoxy pendants proceed smoothly at a reasonable level of dilution (1.25 mM). The structures were fully characterized by HR-ESIMS, FTIR
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Published 11 Mar 2019

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

  • Grzegorz Mlostoń,
  • Małgorzata Celeda,
  • Katarzyna Urbaniak,
  • Marcin Jasiński,
  • Vladyslav Bakhonsky,
  • Peter R. Schreiner and
  • Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

Graphical Abstract
  • this study, the alkylation of 1-adamantyloxy-4,5-diphenylimidazole (8b) with 12b was also attempted under the same conditions. In that case, however, the expected N-alkylation did not occur at room temperature and even after 2 d the starting materials were found unchanged in the reaction mixture. On
  • the other hand, the attempted N-alkylation of 8b upon MW irradiation led to the formation of a mixture of starting materials and some unidentified decomposition products. Due to the great importance of both carbocyclic and heterocyclic systems functionalized with the adamantyl group [27], different
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Published 19 Feb 2019

Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide

  • Pedro N. Batalha,
  • Luana da S. M. Forezi,
  • Maria Clara R. Freitas,
  • Nathalia M. de C. Tolentino,
  • Ednilsom Orestes,
  • José Walkimar de M. Carneiro,
  • Fernanda da C. S. Boechat and
  • Maria Cecília B. V. de Souza

Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35

Graphical Abstract
  • regioselective manner, without the formation of any byproduct derived from the N-alkylation of the amide group. Structural characterization Table 1 gives the nuclear magnetic resonance spectroscopic data that allowed to confirm the structures of substances 5 and 7, and thus also confirmed the regioselectivity of
  • resonance structures due to the adjacent carbonyl, being therefore, less stable (Scheme 5). Reaction paths analysis The paths for the SN2 N-alkylation reaction of both deprotonated species (oxoquinoline and carboxamide N–H units) using bromoethane were obtained. It is worth highlighting that for each of the
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Published 12 Feb 2019

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

  • Abed Tarapdar,
  • James K. S. Norris,
  • Oliver Sampson,
  • Galina Mukamolova and
  • James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

Graphical Abstract
  • give 3. Complete conversion of starting material was observed by 1H NMR, however, the isolated yield of 3 was poor possibly due to competing N-alkylation of the Boc group. Isolation of the O-alkyl product 3 was confirmed by 13C NMR. Despite the poor isolated yield of 3 the mass recovery was more than
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Published 16 Oct 2018
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