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Search for "condensations" in Full Text gives 92 result(s) in Beilstein Journal of Organic Chemistry.

Oxetanes: formation, reactivity and total syntheses of natural products

  • Peter Gabko,
  • Martin Kalník and
  • Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

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  • include the products 137 through Strecker reactions, aldol-type condensations and phosphorus ylide-based olefinations (135) with subsequent Michael additions (138), or sulphinimine and ketone additions (140 and 141, respectively). These common functionalisations are also well documented in a recent
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Published 27 Jun 2025

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

  • Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

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Published 26 Jun 2025

Optimized synthesis of aroyl-S,N-ketene acetals by omission of solubilizing alcohol cosolvents

  • Julius Krenzer and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2025, 21, 1201–1206, doi:10.3762/bjoc.21.97

Graphical Abstract
  • addition, since condensations are affected by the bimolecular addition as an elementary step, special attention to the concentration of the nucleophiles has to be paid. According to Mayr’s nucleophilicity scales [8][9][10], a nucleophilicity parameter N for the specific S,N-ketene acetal intermediate 4 can
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Published 20 Jun 2025

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

  • Chun-Yu Mi,
  • Jia-Yuan Zhai and
  • Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

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  • principles, tandem reactions or annulations can be designed to efficiently access N-heterocycles. As the enamides are also easily accessible via condensations, applications of these nitrogen-containing building blocks in the synthesis of N-heterocycles are synthetically straightforward. When applied properly
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Published 22 May 2025

Heterocycle-guided synthesis of m-hetarylanilines via three-component benzannulation

  • Andrey R. Galeev,
  • Maksim V. Dmitriev,
  • Alexander S. Novikov and
  • Andrey N. Maslivets

Beilstein J. Org. Chem. 2024, 20, 2208–2216, doi:10.3762/bjoc.20.188

Graphical Abstract
  • ring formation via benzannulative inter- or intramolecular condensation of acyclic precursors [27][32][33][34][35][36][37]. Within the latter strategy, [3 + 3] condensations are gaining much attention due to the availability of starting materials and the straightforward installation of the aryl(hetaryl
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Published 02 Sep 2024

Natural resorcylic lactones derived from alternariol

  • Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

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Published 30 Aug 2024

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts

  • Ivana Weisheitelová,
  • Radek Cibulka,
  • Marek Sikorski and
  • Tetiana Pavlovska

Beilstein J. Org. Chem. 2024, 20, 1831–1838, doi:10.3762/bjoc.20.161

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  • -dimethyldichloromethyleniminium chloride and the Vilsmeier reagent, or condensations between o-aminobenzaldehydes and barbituric acid [20][21][23][24][25][26][27]. Neither of these methods allows for the introduction of an aryl substituent into C(5), which confers unique chemical and physical properties on 5-aryldeazaalloxazines
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Published 31 Jul 2024

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

  • Christina Schøttler,
  • Kasper Lund-Rasmussen,
  • Line Broløs,
  • Philip Vinterberg,
  • Ema Bazikova,
  • Viktor B. R. Pedersen and
  • Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

Graphical Abstract
  • variety of reactions; that are, phosphite- or Lawesson’s reagent-mediated olefination reactions (to introduce DTF motifs), Ramirez/Corey–Fuchs dibromo-olefinations followed by Sonogashira couplings (to introduce enediynes motifs), and Knoevenagel condensations (to introduce the vinylic diester motif). By
  • -olefinations, and Knoevenagel condensations. In particular, the acetylenic scaffolds presented in this work may be useful precursors for even more elaborate, conjugated and carbon-rich structures in future work. Experimental Anhydrous MeOH was obtained by distillation from activated Mg and stored over 3 Å
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Published 15 Jan 2024

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

  • Seiji Kawai,
  • Akito Yamada,
  • Yohei Katsuyama and
  • Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

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  • confirmed that the cma cluster is responsible for p-coumaric acid (5) biosynthesis, in which the number of condensations of the malonyl units was one time less than that in the biosynthesis of avenalumic acid. In vitro analysis of recombinant Cma proteins To further understand the biosynthetic machinery
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Published 02 Jan 2024

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

  • Angel Palillero-Cisneros,
  • Paola G. Gordillo-Guerra,
  • Fernando García-Alvarez,
  • Olivier Jackowski,
  • Franck Ferreira,
  • Fabrice Chemla,
  • Joel L. Terán and
  • Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

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  • interesting to note that the levels of induction for the 1,4-addition–aldol condensations are somewhat higher than those obtained for the 1,4-additions. Aldehydes also proved competent terminal electrophiles for the tandem sequence. Illustratively, adducts 23 and 24 were obtained from α-(aminomethyl)acrylates
  • 5 and 8a in 77–88% yields, albeit as poorly selective mixtures of diastereoisomers. This lack of stereocontrol is not surprising, given the well-known difficulty to control the relative configuration between the two adjacent stereocenters created during aldol condensations with zinc enolates
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Published 21 Sep 2023

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

  • Alessandro Brusa,
  • Debora Iapadre,
  • Maria Edith Casacchia,
  • Alessio Carioscia,
  • Giuliana Giorgianni,
  • Giandomenico Magagnano,
  • Fabio Pesciaioli and
  • Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

Graphical Abstract
  • self-aldol condensations, polymerization and Tishchenko-type processes) and stereoselectivity [20]; the activation of acetaldehyde via aminocatalysis, furthermore, suffers from a lack of proper steric hindrance for the enantio-discrimination process. However, some methodologies enabling the use of
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Published 24 Aug 2023

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

  • Till Steinmetz,
  • Blaise Kimbadi Lombe and
  • Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

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  •  4), the biosynthesis starts from hexanoic acid which, upon its thioesterification, is elongated by three decarboxylative Claisen condensations with malonyl-CoA to a 6-pentylsalicyl thioester. A condensation with cysteine and a subsequent cyclization generate a 6-pentylsalicyl-thiazolinyl thioester
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Published 23 Jun 2023

Nucleophile-induced ring contraction in pyrrolo[2,1-c][1,4]benzothiazines: access to pyrrolo[2,1-b][1,3]benzothiazoles

  • Ekaterina A. Lystsova,
  • Maksim V. Dmitriev,
  • Andrey N. Maslivets and
  • Ekaterina E. Khramtsova

Beilstein J. Org. Chem. 2023, 19, 646–657, doi:10.3762/bjoc.19.46

Graphical Abstract
  • -aminothiophenol with donor–acceptor cyclopropanes (Scheme 2, entry 10) [27], condensations of o-aminothiophenol with 4-oxo acids or their derivatives (Scheme 2, entry 11) [2][28][29][30][31] and cascade reactions of o-aminothiophenol, furfural and anhydrides of 2,3-unsaturated carboxylic acids (Scheme 2, entry 12
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Published 11 May 2023

Oxa-Michael-initiated cascade reactions of levoglucosenone

  • Julian Klepp,
  • Thomas Bousfield,
  • Hugh Cummins,
  • Sarah V. A.-M. Legendre,
  • Jason E. Camp and
  • Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

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  • ]. These types of oxa-Michael initiated aldol condensations were also of interest to us due to the previous work conducted on aldol adducts of 1 [14][21], and the potential to generate bio-derived chiral materials with reactive functional groups. We envisaged that the development of a larger library of
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Published 13 Oct 2022

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

  • Hao Guo,
  • Yu-Fei Ao,
  • De-Xian Wang and
  • Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

Graphical Abstract
  • , macrocyclic condensations were then pursued. The homo-condensations between the homologous bisamine and bisisothiocyanate fragments were firstly tried (Scheme 1b). In the presence of an organic base, reactions between 4a–f and 5a–f went smoothly and afforded the desired macrocycle products M1–M6 in 35–72
  • , hetero-condensations between different bisamine and bisisothiocyanate fragments, including combination of different chiral configurations, were also investigated (Scheme 1c). Reactions between cyclohexanediamine-derived bisamine fragments 4a or the enantiomers ent-4a–c with diphenylethylenediamine
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Published 02 May 2022

A Se···O bonding catalysis approach to the synthesis of calix[4]pyrroles

  • Qingzhe Tong,
  • Zhiguo Zhao and
  • Yao Wang

Beilstein J. Org. Chem. 2022, 18, 325–330, doi:10.3762/bjoc.18.36

Graphical Abstract
  • bonding interactions between phosphonium selenides and carbonyls can significantly activate carbonyl groups [41][42][43], thus providing a new opportunity to develop carbonyl chemistry. To expand the catalysis capability of chalcogen bonding interactions, we envisioned that consecutive condensations
  • efficiently at room temperature. We note that this reaction did not stop at a bis(pyrrole)methane stage, but consecutive condensations between four molecules of acetone and four molecules of pyrrole took place to give calix[4]pyrrole 2a in 91% yield after 4 h (Scheme 2). Further investigations revealed that
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Published 18 Mar 2022

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

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  • was unavoidable, and multiple chromatographic separations reduced the isolated yields. Such contamination with phosphorus-containing byproducts is a well-known problem in Eschenmoser condensations [30]. With particularly difficult separations we simply subjected the impure intermediates (for most of
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Published 13 Oct 2021

One-step synthesis of imidazoles from Asmic (anisylsulfanylmethyl isocyanide)

  • Louis G. Mueller,
  • Allen Chao,
  • Embarek AlWedi and
  • Fraser F. Fleming

Beilstein J. Org. Chem. 2021, 17, 1499–1502, doi:10.3762/bjoc.17.106

Graphical Abstract
  • ). Trapping lithiated Asmic with 1-methyl-1H-indole-3-carbonitrile afforded indole 7l whereas trapping with ethyl N-phenylformimidate afforded the selectively N-1 protected imidazole 7m (Scheme 2) [21]. Collectively, the condensations of lithiated Asmic with nitriles or an imidate provides an efficient route
  • . Anisylsulfanylimidazole reduction to monosubstituted imidazoles. Asmic condensations to imidazoles. Supporting Information Supporting Information File 213: Experimental procedures and spectral data of all synthesized compounds. Supporting Information File 214: Raw FID files. Acknowledgements Dr. Caleb Holyoke, Jr. is
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Published 24 Jun 2021

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

  • Guido Gambacorta,
  • James S. Sharley and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

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  • catalyst for continuous-flow aldol condensations. A solution of the reagents was directed into the stainless steel module, containing a series of five hollow fibres, perpendicular to the fibre alignment. The solution permeates the fibres and is pushed through the reactor using a nitrogen flow stream
  • remains a relatively under-explored area of research. While the majority of reported examples have been of academic origin, there is a high level of interest in the pursuit of aldol reactions in flow by industry. The production of α,β-unsaturated C10-aldehydes [116] as multiphase aldol condensations in
  • . In 2008, the group of Sartori developed a flow setup for nitroaldol condensations of different benzaldehydes exploiting a silica-supported amine (KG-60-NH2) as a heterogeneous catalyst (Scheme 21) [133]. Secondary and tertiary amine-supported catalysts were also investigated, although they were found
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Published 18 May 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

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  • pyridinium p-toluenesulfonate (PPTS) also worked well to perform these condensations [1][16]. For the formation of aldimines, other methodologies are described in the literature using condensation reagents such as Yb(OTf)3 [17], Cs2CO3 [18] and KHSO4 [19]. However, for the synthesis of ketimines, Ti(OEt)4
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Published 12 May 2021

Synthetic accesses to biguanide compounds

  • Oleksandr Grytsai,
  • Cyril Ronco and
  • Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

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Published 05 May 2021

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

  • Rashmi Singh,
  • Tomas Horsten,
  • Rashmi Prakash,
  • Swapan Dey and
  • Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79

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  • . Electrophilic substitution and further condensations give polycyclic systems, including oxazolo- and chromeno-fused analogues. Keywords: benzofuropyridines; benzoquinones; dibenzofurans; Meerwein reaction; metal-free synthesis; Introduction Dibenzofurans are important oxygen-containing heterocycles present in
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Published 30 Apr 2021

Synthetic strategies of phosphonodepsipeptides

  • Jiaxi Xu

Beilstein J. Org. Chem. 2021, 17, 461–484, doi:10.3762/bjoc.17.41

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  • phosphonylation of hydroxy esters 2 with N-protected aminoalkylphosphonochloridates 3 (method I), reactions of N-protected aminoalkylphosphonic monoesters 4 with hydroxy esters 2 (method II) or with 1-(alkoxycarbonyl)alkyl halides or sulfonates 5 (method III), pseudo-four-component condensations (method IV), and
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Published 16 Feb 2021

A heterobimetallic tetrahedron from a linear platinum(II)-bis(acetylide) metalloligand

  • Matthias Hardy,
  • Marianne Engeser and
  • Arne Lützen

Beilstein J. Org. Chem. 2020, 16, 2701–2708, doi:10.3762/bjoc.16.220

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  • equivalents of water per imine function that originate from the hydrate salt and imine condensations. Following this approach, the heterobimetallic cage 4 was obtained as a dark purple solid in 87% yield. Interestingly, complex 4 turned out to be rather stable as a solid under ambient conditions for several
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Published 03 Nov 2020

Synthesis of new asparagine-based glycopeptides for future scanning tunneling microscopy investigations

  • Laura Sršan and
  • Thomas Ziegler

Beilstein J. Org. Chem. 2020, 16, 888–894, doi:10.3762/bjoc.16.80

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  • Table 1, the yields for all condensations with HBTU and HATU are in a comparable range. Only for the cellobiosyl Asp amino acid 3f (Table 1, entry 6), the lactosylated Asp–Phe–Ala tripeptide 6e (Table 1, entry 23), and the galactosylated Asp–Trp dipeptide 5b (Table 1, entry 14), HATU gave a
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Published 30 Apr 2020
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