Search results

Search for "transesterification" in Full Text gives 99 result(s) in Beilstein Journal of Organic Chemistry.

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

  • Luan A. Martinho and
  • Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

Graphical Abstract
  • and methyl isocyanoacetate furnished the desired products (4ff–ii and 4jj–ll, respectively) in moderate yields (55–68%), possibly due to the lower reactivity of these isocyanides compared to tert-butyl and cyclohexyl isocyanides [54]. In the latter cases, transesterification of the ester group with
PDF
Album
Supp Info
Full Research Paper
Published 19 Mar 2024

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

  • Dmitry B. Vinogradov,
  • Alexei N. Izmest’ev,
  • Angelina N. Kravchenko,
  • Yuri A. Strelenko and
  • Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

Graphical Abstract
  • NMR reaction monitoring showed that compound 1d under conditions of excess of KOH in methanol undergoes alkaline hydrolysis along with transesterification of the ester group to give the ring-opened form 6d (Scheme 4), the maximum concentration of which was observed approximately 30 minutes after the
PDF
Album
Supp Info
Full Research Paper
Published 28 Jul 2023

Synthesis of medium and large phostams, phostones, and phostines

  • Jiaxi Xu

Beilstein J. Org. Chem. 2023, 19, 687–699, doi:10.3762/bjoc.19.50

Graphical Abstract
  • ][1,2]oxaphosphinine 4-oxide (66) and 1-phenyl-3,4-dihydronaphtho[1,8-cd][1,2]oxaphosphepine 1-oxide (67) in 70:30 in a total 99% yield (Scheme 14) [35]. 1.4 Synthesis via P–O bond formation Intramolecular transesterification is a common method for the synthesis of various phostones and phostines [13
  • of the etheric oxygen atom and the antibonding orbital of the P=O bond (the stereoelectronic effect), leading to the more stable anti-diastereomer 74 (Scheme 16) [38]. In the phostone 74 was installed a linker 2-(5-aminopentoxy) group via transesterification with benzyl N-(5-hydroxypentyl)carbamate
  • intramolecular transesterification. The method was also applied in the derivatization of a steroid derivative 95, affording the corresponding product 96 (Scheme 19) [42]. The reactions are [6 + 1] and [7 + 1] annulations for cyclohex-2-enone and cyclohept-2-enone, respectively. The treatment of (M)-2'-methyl
PDF
Album
Review
Published 15 May 2023

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

  • Jorge de Lima Neto and
  • Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

Graphical Abstract
  • (91) was prepared from the borylation reaction of 4-bromobenzaldehyde (52, Scheme 18) [50]. The coupling reaction [23][24][25] between 14 and 91 gave the corresponding diaryl ether 16 in 68% yield. Subsequent transesterification reaction [51] using dibutyltin oxide and allylic alcohol led to the
  • the authors consisted in the ring closure through a metathesis reaction using the Grubbs catalyst [52][53]. The required compound 99 was prepared by converting compound 16 into the styrene 98 via a Wittig reaction followed by a transesterification to yield the desired allylic ester. Several reaction
PDF
Album
Review
Published 29 Mar 2023

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

  • Nicoleta G. Hădărugă,
  • Gabriela Popescu,
  • Dina Gligor (Pane),
  • Cristina L. Mitroi,
  • Sorin M. Stanciu and
  • Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

Graphical Abstract
  • flavonolignans as impurities) and were purchased from Sigma-Aldrich, St. Louis, MO, USA. Ethanol used for complex synthesis was of 96% concentration (v/v) and was purchased from ChimReactiv (Bucharest, Romania). The analysis of the FA profile of the hazelnut oil required the derivatization (transesterification
  • . Derivatization was performed by quantitative transesterification in a 100 mL one-necked flask equipped with reflux condenser. 5 mL of BF3·MeOH 20% and ≈100 mg of hazelnut oil were used for derivatization. The mixture was refluxed for at least 30 min, until no oil remained. Then, 2 mL of hexane was added and the
  • mixture refluxed for another 15 min for completing the transesterification. The organic layer was separated in the neck region by adding a sufficient amount of saturated sodium chloride solution. The organic layer was transferred into a GC vial with ≈0.5 g of anhydrous sodium sulfate and stored at 4 °C
PDF
Album
Supp Info
Full Research Paper
Published 28 Mar 2023

An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

  • Stephen J. I. Shearan,
  • Enrico Andreoli and
  • Marco Taddei

Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160

Graphical Abstract
  • hydrolysis using the method put forward by McKenna et al. (1977), which involves the use of trimethylbromosilane (TMSiBr) in a transesterification of the dialkyl phosphonate to bis(trimethylsilyl) phosphonate, followed by treatment in water or short-chain alcohols to obtain a phosphonic acid, as shown in
PDF
Album
Supp Info
Letter
Published 07 Nov 2022

Vicinal ketoesters – key intermediates in the total synthesis of natural products

  • Marc Paul Beller and
  • Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

Graphical Abstract
  • -substitution. Subsequent transesterification gave the α-ketoester 75, which was used in a Wittig reaction. The undesired Z-configured double bond was isomerized to the E-alkene and final hydrogenation delivered corynoxine (76). (+)-Gracilamine The Mannich reaction was also used by Nagasawa et al. as a key step
PDF
Album
Review
Published 15 Sep 2022

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

  • Daniele Rocco,
  • Ana A. Folgueiras-Amador,
  • Richard C. D. Brown and
  • Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

Graphical Abstract
  • as ligands in organometallic catalysts [9] and as versatile organocatalysts [10] in a very wide range of organic reactions such as classical benzoin condensation, transesterification, acylation, Knoevenagel reaction, Claisen condensation etc. The electrochemical generation of carbenes from ILs avoids
PDF
Album
Full Research Paper
Published 05 Aug 2022

Synthesis of odorants in flow and their applications in perfumery

  • Merlin Kleoff,
  • Paul Kiler and
  • Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

Graphical Abstract
  • ][28][29][30][31]. More recently, Paradisi and co-workers disclosed a more general access to a variety of esters with mainly fruity and floral odorants by transesterification of acyl donors of structure 12 to the corresponding alcohols 11 using an immobilized transferase obtained from Mycobacterium
  • ) to (+)-nootkatone (8) under catalyst and solvent-free conditions in a segmented flow. Enzyme-catalyzed acetylation of isoamyl alcohol (9) in a biphasic n-heptane/water mixture utilizing a CorningTM Low Flow reactor. Esterification of alcohols by transesterification, catalyzed by immobilized
PDF
Album
Review
Published 27 Jun 2022

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

  • Prodip Howlader and
  • Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

Graphical Abstract
  • catalysts that allow ON/OFF reaction control in photoredox catalysis [120], phosphate diester transesterification [121], Friedel–Crafts reaction, ring opening of epoxides, oligomerization [116], and acyl-transfer reactions [122][123]. While there are further examples by Mirkin [124][125][126], Schmittel
PDF
Album
Review
Published 27 May 2022

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

  • Martin Vrbický,
  • Karel Macek,
  • Jaroslav Pochobradský,
  • Jan Svoboda,
  • Miloš Sedlák and
  • Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

Graphical Abstract
  • transesterification (cyclization) led to the desired products 1 and 2. In the case of amides 27 and 28, the reaction conditions for the cyclization were slightly modified, i.e., the reaction time was prolonged to 24 h and the precipitated product was washed with hexane to remove traces of borneol. No changes in the
PDF
Album
Supp Info
Full Research Paper
Published 14 Apr 2022

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

  • Soumyadip Basu,
  • Sauvik Chatterjee,
  • Suman Ray,
  • Suvendu Maity,
  • Prasanta Ghosh,
  • Asim Bhaumik and
  • Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

Graphical Abstract
  • delivery [11], biomedical uses [12], removal of toxic metals from wastewater [13], in manufacturing processes [14], in the food industry [15], in agriculture [16], and as catalyst in transesterification reactions [17]. Chitosan is regarded as one of the most effective bio-based polymers to chelate
PDF
Album
Supp Info
Full Research Paper
Published 25 Jan 2022

Efficient and regioselective synthesis of dihydroxy-substituted 2-aminocyclooctane-1-carboxylic acid and its bicyclic derivatives

  • İlknur Polat,
  • Selçuk Eşsiz,
  • Uğur Bozkaya and
  • Emine Salamci

Beilstein J. Org. Chem. 2022, 18, 77–85, doi:10.3762/bjoc.18.7

Graphical Abstract
  • (Figure 2) [28]. The formation of lactone 10 can again be explained by participation of the neighbouring group, as discussed above. However, during the purification on silica gel of the lactone-Boc product, its transesterification also resulted in corresponding methyl carbamate 10. We then investigated
  • , which is a typical transesterification reaction. To explain the formation of lactone 10, we performed a series of DFT computations using the Gaussian 16 software [29]. For this purpose, we performed geometry optimizations using the B3LYP functional [30][31][32][33]. Vibrational frequencies were computed
PDF
Album
Supp Info
Full Research Paper
Published 06 Jan 2022

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

  • Umesh P. Aher,
  • Dhananjai Srivastava,
  • Girij P. Singh and
  • Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

Graphical Abstract
  • transesterification to give the hemithioacetal 39, which cyclized to the oxathiolane 40 in situ with minor isomerization. The reduction of the ester group with LiAlH4, followed by benzoylation using benzoyl chloride and pyridine gave 1,3-oxathiolane derivative 41. Kraus and Attardo [48] developed new strategies for
PDF
Album
Review
Published 04 Nov 2021

Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)

  • Tania Xavier,
  • Sylvie Condon,
  • Christophe Pichon,
  • Erwan Le Gall and
  • Marc Presset

Beilstein J. Org. Chem. 2021, 17, 2085–2094, doi:10.3762/bjoc.17.135

Graphical Abstract
  • undesired transesterification reactions, which somewhat limits the usefulness of this strategy. Upon application of these precautions, yields ranging from 62% to 91% were obtained in most cases. Nevertheless, the use of some protective groups is obviously a limitation of the method as this second step was
PDF
Album
Supp Info
Full Research Paper
Published 18 Aug 2021

Electron-rich triarylphosphines as nucleophilic catalysts for oxa-Michael reactions

  • Susanne M. Fischer,
  • Simon Renner,
  • A. Daniel Boese and
  • Christian Slugovc

Beilstein J. Org. Chem. 2021, 17, 1689–1697, doi:10.3762/bjoc.17.117

Graphical Abstract
  • evaluation of the NMR spectra indicate, among repeating units from oxa-Michael and transesterification reactions [30][31], the presence of Rauhut–Currier-derived linkages [32][33][34]. This repeat unit is characterized by peaks at 6.22 and 5.64 ppm in the 1H NMR spectrum and at 126.6, 33.0, 27.3 ppm in the
PDF
Album
Supp Info
Full Research Paper
Published 21 Jul 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

Graphical Abstract
PDF
Album
Review
Published 18 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

Graphical Abstract
  • transesterification of several vegetable oils [5]. Since the first reported copper-biguanide complex, the synthesis of a variety of stable biguanide complexes has been reported with VIV, CrIII, MnIII, MnIV, CoII, CoIII, NiII, CuII, ZnII, PdII, ReV, OsVI [8], etc. Many of these complexes found applications as
  • . Later, several groups performed the addition of N,N,N’,N’-tetramethylguanidine (TMG) to carbodiimides in order to produce the corresponding hexasubstituted biguanides (Scheme 39). These latter compounds found applications as strong organic bases [79], catalysts in transesterification reactions for the
  • neat for 30 min, or 24 h diluted in an apolar solvent. Both of these conditions proved very efficient even for hindered reagents and displayed good to excellent yields (Scheme 39B). In the search for new biguanide-based organocatalysts for the transesterification of vegetable oils, Glasovac et al
PDF
Album
Review
Published 05 May 2021

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

  • Peter Jonas Wickhorst,
  • Mathilda Blachnik,
  • Denisa Lagumdzija and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

Graphical Abstract
  • conditions to give the corresponding 9-methoxy-substituted derivatives 5a–e in moderate to good yields of 40–77% (Scheme 1). During the methylation of derivative 5f a transesterification occurred and a 2:1 mixture of the ethyl and methyl ester was formed that could not be further separated. The novel
PDF
Album
Supp Info
Full Research Paper
Published 04 May 2021

Kinetics of enzyme-catalysed desymmetrisation of prochiral substrates: product enantiomeric excess is not always constant

  • Peter J. Halling

Beilstein J. Org. Chem. 2021, 17, 873–884, doi:10.3762/bjoc.17.73

Graphical Abstract
  • close to 1 for many transaminase or transesterification reactions, but may be substantially higher, if activated donors are used. Effect of the key ee decline parameter (eeDP) of the enzyme on the product ee for “ping-pong, second” kinetics. S0 = 0.2 M, D = 0.4 M, E = 39, KMS = 0.01 M, k2 = 1000 s−1
PDF
Album
Supp Info
Full Research Paper
Published 21 Apr 2021

Valorisation of plastic waste via metal-catalysed depolymerisation

  • Francesca Liguori,
  • Carmen Moreno-Marrodán and
  • Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

Graphical Abstract
  • conditions. For instance, for polyesters, alcoholysis may provide mixed monomers formally derived from transesterification reactions [89][90], while aminolysis provides amides and alcohols [91][92]. In the search of “greener” technologies for plastic recycling, catalytic hydrogenolysis processes have been
  • , polyurethanes, polyisocyanurates and resins [43]. Among the various glycols, EG is the most popular, resulting in the formation of BHET, formally through a (reversible) transesterification reaction (Scheme 5) [198]. Drawbacks of this method are the difficulty of purification of BHET, the need of an excess of EG
  • PET/PLA plastic waste. It was suggested that the different reactivity between PLA and PET is attributable to the amorphous, less rigid structure of PLA and to the potential of forming five-membered chetate ring intermediates between Zn(II) ions and lactate units, which favour the transesterification
PDF
Album
Review
Published 02 Mar 2021

Synthetic strategies of phosphonodepsipeptides

  • Jiaxi Xu

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

Graphical Abstract
  • -phosphonodepsipeptides 1. The N-protected aminoalkylphosphonic monomethyl/ethyl esters are very useful materials for the preparation of N-protected aminoalkylphosphonochloridates 3. N-Protected aminoalkylphosphonic diaryl esters should be converted into the corresponding monomethyl/ethyl esters via transesterification
  • ) were modest inhibitors. The synthesis started from diphenyl N-Cbz-1-aminoalkylphosphonates 11 (Scheme 1). They were transformed to dimethyl esters via transesterification and further to monomethyl esters 12 via basic hydrolysis. After chlorination with thionyl chloride, the monomethyl esters 12 were
PDF
Album
Review
Published 16 Feb 2021

Identification of volatiles from six marine Celeribacter strains

  • Anuj Kumar Chhalodia,
  • Jan Rinkel,
  • Dorota Konvalinkova,
  • Jörn Petersen and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 420–430, doi:10.3762/bjoc.17.38

Graphical Abstract
  • , for which all relevant enzymes are encoded in the six Celeribacter strains (only a DmdA homolog is missing in C. indicus, Table S1 in Supporting Information File 1), and e.g., transesterification of the DmdC product with EtOH (Scheme 1A). Compound 42 is not a widespread sulfur volatile, but has been
PDF
Album
Supp Info
Full Research Paper
Published 11 Feb 2021

Regioselective chemoenzymatic syntheses of ferulate conjugates as chromogenic substrates for feruloyl esterases

  • Olga Gherbovet,
  • Fernando Ferreira,
  • Apolline Clément,
  • Mélanie Ragon,
  • Julien Durand,
  • Sophie Bozonnet,
  • Michael J. O'Donohue and
  • Régis Fauré

Beilstein J. Org. Chem. 2021, 17, 325–333, doi:10.3762/bjoc.17.30

Graphical Abstract
  • -arabinofuranosides were significantly shortened (from 7 or 8 to 4–6 steps), and the transesterification yields were enhanced (from 46 to 73% and from 47 to 86%, respectively). This was achieved using enzymatic (immobilized Lipozyme® TL IM from Thermomyces lanuginosus) transesterification of unprotected vinyl
  • ; hydrolysis; lipase; transesterification; Introduction The development of “white biotechnology” is underpinned by advances in enzyme discovery and engineering, areas that are being driven by metagenomics and in vitro-directed enzyme evolution. These techniques procure massive discovery or the creation of new
  • molecule [12][15][16][17]. Additionally, the temporary protection of the functional groups is sometimes used during the synthesis in order to facilitate certain steps. Using an alternative approach, we employed a one-step regioselective transesterification of the unprotected vinyl ferulate 2 (synthesized
PDF
Album
Full Research Paper
Published 01 Feb 2021

The preparation and properties of 1,1-difluorocyclopropane derivatives

  • Kymbat S. Adekenova,
  • Peter B. Wyatt and
  • Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

Graphical Abstract
  • [81]. The authors obtained the chiral monoacetate intermediates (R)-78 and (S)-80 by lipase-catalyzed methods. The lipase-catalyzed asymmetric transesterification of prochiral diol 77 and the deacetylation of the prochiral diacetate 79 resulted in the formation of the (R)-monoacetate (R)-78 and (S
  • )-monoacetate (S)-80, respectively (Scheme 32). As for the transesterification, a high yield (96.5%) and enantioselectivity (91.3% ee) were obtained using lipase PS in benzene. In the case of the deacetylation, the use of Amano PS lipase in acetone gave a high yield (86.2%), enantioselectivity (91.7% ee), and
PDF
Album
Review
Published 26 Jan 2021
Other Beilstein-Institut Open Science Activities