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Search for "acetylation" in Full Text gives 238 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Inline purification in continuous flow synthesis – opportunities and challenges

  • Jorge García-Lacuna and
  • Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

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  • only. This is facilitated when using heterogeneous catalysts or immobilized enzymes that are retained in cartridge reactors. For instance, Paradisi and co-workers reported an N-acetylation approach to produce melatonin analogs, where the pure product is obtained in the organic phase after evaporation
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Published 16 Dec 2022

Total synthesis of grayanane natural products

  • Nicolas Fay,
  • Rémi Blieck,
  • Cyrille Kouklovsky and
  • Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

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  • suitable starting material for the SmI2-promoted pinacol coupling, directed by the free hydroxy group, affording a complete selectivity in the formation of the 7-membered ring B. The synthesis of grayanotoxin III was then achieved by acetylation of the secondary alcohols, oxidative cleavage of the MOM
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Review
Published 12 Dec 2022

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

  • Konstantin Lebedinskiy,
  • Volodymyr Lobaz and
  • Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

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  • as the price of some reagents and relatively low yields. In this work, we describe a method using low-cost reactants, such as methyl tosylate and DIPEA, which provides moderate to high yields and is a reasonable alternative to the existing methods. The acetylation of compound 1 using standard
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Published 25 Nov 2022

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling

  • Elenilson F. da Silva,
  • Krist Helen Antunes Fernandes,
  • Denise Diedrich,
  • Jessica Gotardi,
  • Marcia Silvana Freire Franco,
  • Carlos Henrique Tomich de Paula da Silva,
  • Ana Paula Duarte de Souza and
  • Simone Cristina Baggio Gnoatto

Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161

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  • . Initially, 1-azido-3-nitrobenzene (c) was obtained from m-nitroaniline (a) (Scheme 1) with excellent yields (98%), as previously described [41]. The protection of the 3β-OH group of the triterpene skeleton was carried out by acetylation using acetic anhydride to prevent cleavage in acidic conditions, which
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Published 09 Nov 2022

Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure

  • Irene Torres-García,
  • Josefa L. López-Martínez,
  • Rocío López-Domene,
  • Manuel Muñoz-Dorado,
  • Ignacio Rodríguez-García and
  • Miriam Álvarez-Corral

Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132

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  • stereoselective kinetic resolution of allenol 3 via lipase AK-catalyzed acetylation [15]. In this way, unaltered, (−)-hydroxyallene 3 could be separated from (+)-acetyl derivative 9 through standard column chromatography (Scheme 3). Enantiomeric excesses of (−)-3 and (+)-9 were determined by chiral HPLC analyses
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Published 19 Sep 2022

From amines to (form)amides: a simple and successful mechanochemical approach

  • Federico Casti,
  • Rita Mocci and
  • Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

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  • ][50][51][52][53][54], no systematic report of N-formylation and N-acetylation by ball milling has been reported yet. Here, we describe two complementary procedures to prepare formamides and acetamides, applied to primary and secondary aromatic and aliphatic amines. The methodologies directly involve
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Published 12 Sep 2022

Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

  • Houchao Xu,
  • Anne Wochele,
  • Minghe Luo,
  • Gregor Schnakenburg,
  • Yuhui Sun,
  • Heike Brötz-Oesterhelt and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

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  • -butyloxycarbonyl (Boc)-protected threonine using bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl) [14][15] and Hünig’s base to give 9. Cleavage of the Boc group with 5% TFA followed by basic treatment resulted in the cyclisation to the dioxopiperazine 10. Acetylation and subsequent treatment with LiClO4 and
  • DBU is a common strategy for the dehydration of serine and threonine units in peptides [16], but unfortunately the acetylation of 10 failed. Interestingly, the direct treatment of 10 with LiClO4 and DBU under prolonged reaction times (3 days) resulted in the elimination of water. This reaction
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Published 07 Sep 2022

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

  • Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

Graphical Abstract
  • . When acetic anhydride was employed as electrophile, besides the protonated product 136a, two different alkylated products 147 and 148 were formed depending on the reaction time. The 1-acetoxylvinylated and 3-hydroxybut-2-enoylated products 147 and 148 were obtained, respectively, through O-acetylation
  • and C-acetylation followed by enolization of the first generated acetylated benzocyclohexadiene-fused γ-phosphinolactams 149. The results indicated that short reaction times favored O-acetylation, while long reaction times preferred C-acetylation (Scheme 25) [52]. They further investigated various α,β
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Published 22 Jul 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
  • a method for the acetylation of isoamyl alcohol (9) catalyzed by Candida antarctica lipase B (Scheme 3) [26]. A biphasic system consisting of n-heptane and an aqueous buffer solution is used and efficiently mixed in a Corning AFRTM Low Flow reactor providing a fine dispersion of the reaction mixture
  • min isoamyl acetate (10) is obtained in 59% yield according to GC analysis [26]. Related methods for the enzyme-catalyzed acetylation of isoamyl alcohol (9) have been developed utilizing biphasic systems, supercritical carbon dioxide as a solvent, or packed-bed reactors with immobilized enzymes [27
  • layer is mixed with vinyl acetate (53) and pumped through a column reactor containing Candida antarctica lipase A. At 30 °C and with a residence time of 11 min, acetylation of cis-alcohol 52 is mediated. After distillation, cis-woody acetate 54 is obtained in 89% isolated yield (de > 99%) on a gram
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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
  • 132 and the acetylation agent 133 (Figure 30) were reacted in the presence of the copper(I)-loaded rotor [Cu2(130)]2+ no reaction was detected. In contrast, the dimeric complex [Fe(Cu2(130))2]6+, formed after addition of iron(II) ions, offers two cavities each with two copper(I) ions to pre-bind both
  • 132 and 133 at an optimal reaction distance. It was no surprise, that due to the increased local concentration, the acetylation 132 + 133 → 134 did rapidly take place. Similarly, the bigger dimeric nanoswitch [Fe(Cu2(131))2]6+ catalyzed the acetylation of the larger substrate 136 due to size-matching
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Published 27 May 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

Graphical Abstract
  • (Scheme 21). Dobrinescu and co-workers studied, besides acetylation reactions, the hydroacetylation of menadione for the synthesis of diacetylated menadiol derivatives through heterogeneous catalysis [121]. The first methodology involved the reduction of menadione (10) to menadiol (14), with sodium
  • dithionite, followed by hydroacetylation of 14 with acetic anhydride, using nanoscopic acidic hydroxylated metal fluorides MFn-x(OH)x (M = Mg, Al; n = 2, 3; x < 0.1) as catalysts. This type of catalysts has a huge acidic versatility, once they can behave as Brønsted or Lewis acids. The reductive acetylation
  • of 10 occurred in two steps and at high selectivity conversion rates when using AlF3-57 and MgF2-71 (Scheme 22A). The second proposal explored the reductive acetylation reaction of menadione (10) with acetic anhydride catalyzed by gold(III) deposited on the qualified metallic fluorides. The
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Published 11 Apr 2022

Synthesis and late stage modifications of Cyl derivatives

  • Phil Servatius and
  • Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

Graphical Abstract
  • B (Figure 1) is a cyclic tetrapeptide with a rather unusual epoxyketone side chain and was found to be a strong inhibitor of histone deacetylases (HDACs) [4][5]. HDACs are nuclear isozymes that regulate gene transcription via a dynamic process of acetylation and deacetylation of lysine residues of
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Published 04 Feb 2022

Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

  • Sandeep Kumar,
  • Jyotirmoy Maity,
  • Banty Kumar,
  • Sumit Kumar and
  • Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

Graphical Abstract
  • -glucofuranose following chemoenzymatic and chemical routes in 34–35% and 24–25% overall yields, respectively. The quantitative and diastereoselective acetylation of primary hydroxy over two secondary hydroxy groups present in the key nucleoside precursor was mediated with Lipozyme® TL IM in 2
  • acetylation; Introduction In the last few decades, modification of nucleoside/nucleotide analogues has been a field of keen interest to researchers due to their therapeutic properties for treatment of cancer, viral and microbial infections [1][2][3][4][5][6][7][8][9]. The very first cytotoxic
  • % overall yield starting from compound 11, respectively (Scheme 2). The use of lipase as biocatalyst was employed for the selective acetylation of the primary hydroxy group present in trihydroxy nucleosides 14a,b. This led to the screening of two different lipases, viz Candida antarctica lipase-B (CAL-B
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Published 11 Jan 2022

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

  • Shun Saito,
  • Kanji Indo,
  • Naoya Oku,
  • Hisayuki Komaki,
  • Masashi Kawasaki and
  • Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

Graphical Abstract
  • components by COSY and HMBC correlations established 6-prenylated N-acetyltryptophan (Figure 5). The N-acetylation was evident from HMBC correlations from the amide (NH-11) and acetyl methyl protons (H-13) to the amide carbon (C-12), while prenylation at C-6 was supported by HMBC correlations from H-5 and H
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Published 16 Dec 2021

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

  • Haopei Wang and
  • Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

Graphical Abstract
  • . Following acetylation of the reaction mixture, we were able to isolate small quantities of O-acetyl N-hydroxyindole (9, Figure 3e), although the initial byproduct N-hydroxyindole itself proved too unstable to be isolated. It is noteworthy within this context that hydroxyindole is a C8 compound, consistent
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Published 15 Dec 2021

Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

  • Tanmoy Halder and
  • Somnath Yadav

Beilstein J. Org. Chem. 2021, 17, 2915–2921, doi:10.3762/bjoc.17.199

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  • 73%. The structure of the trisaccharide was confirmed by comparison of its NMR and HRMS spectral data with that of the previously synthesized product by the linear strategy. With the protected trisaccharide 2 in hand, it remained to carry out the N-acetylation and the removal of the protecting groups
  • on the hydroxy groups. First, the concomitant removal of the Troc group and the N-acetylation was achieved using Zn/AcOH/Ac2O 3:2:1 as reagent in one pot (Scheme 6) [52]. Then, O-deacetylation was accomplished by using a catalytic amount of NaOMe in MeOH at room temperature. Finally, the benzylidene
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Published 13 Dec 2021

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
  • was prepared from ᴅ-mannose (3c) by protecting the primary alcohol with a tosyl group, followed by protection of the four hydroxy groups by acetylation. Further, bromo-substituted sugar compound 10 was obtained by a bromination reaction of the anomeric acetyl group. 1,6-Thioanhydro-β-mannose
  • hydroxyoxathiolane 32. Further, acetylation of the hydroxyoxathiolane in the presence of methanesulfonic acid gave a 1:2 mixture of the trans-diastereomer 33 and the cis-diastereomer 34. The esterification using ʟ-menthol as a chiral auxiliary resulted in a diastereomeric mixture, which was successfully
  • afforded the thiol compound 3nb. Further treatment of the thiol 3nb with methyl glyoxylate in dichloromethane solvent along with molecular sieves (4 Å), followed by in situ acetylation using Ac2O, pyridine, and catalytic 4-(N,N-dimethylamino)pyridine (DMAP) provided compound 37. The second route involves
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Published 04 Nov 2021

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

  • Dušan Đ. Škorić,
  • Olivera R. Klisurić,
  • Dimitar S. Jakimov,
  • Marija N. Sakač and
  • János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

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  • selective acetylation [43], followed by oxidation. Enones 4 and 8 were prepared by dehydrogenation of corresponding ketones with SeO2 in refluxing acetic acid [44]. Microwave-assisted heating of the reaction mixture in a closed vessel (150 °C) helped in decreasing the reaction time for dehydrogenation
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Published 20 Oct 2021

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

  • Sumana Mandal,
  • Raju D. Chaudhari and
  • Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

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  • in the key step for the synthesis of (±)-thallusin (207, Scheme 62). A complex mixture of Hg(OTf)2 and N,N-dimethylaniline (DMA) (1.2 equiv) was initially used for olefin cyclization to produce a regio- and a stereoisomeric mixture of acetate 205 after reduction and acetylation of the crude product
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Published 09 Sep 2021

Progress and challenges in the synthesis of sequence controlled polysaccharides

  • Giulio Fittolani,
  • Theodore Tyrikos-Ergas,
  • Denisa Vargová,
  • Manishkumar A. Chaube and
  • Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

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  • tuning of the DP and fraction of acetylation (FA). Chitooligosaccharides (COS: β(1–4)-linked oligomers of GlcNAc and/or GlcN) have gained popularity due to their exceptional antimicrobial, antitumor, and immune modulatory activities [29][213][214][215][216][217]. Methods to obtain well-defined COS with
  • COS, which requires tedious purification steps. Furthermore, degradation of natural chitin often lacks proper control over the pattern of acetylation (PA). Acetolysis also often leads to heterogeneous mixtures [232][233][234][235]. A controlled acetolysis of chitin, followed by the one-pot trans-N
  • were removed with hydrazine under reflux and the free amino groups were acetylated to obtain the fully N-acetylated COS [255]. Control over the pattern of N-acetylation was for the first time achieved using two monosaccharides bearing an azido (N3) and a N-Phth moieties as precursors of the free and N
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Published 05 Aug 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

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  • effect by Conrow et al. to give regioselective access to N-1 alkylindazoles on kilogram scale, albeit over two steps from the corresponding N-1 acylindazole via reductive acetylation–deacetoxylation [20]. Although electronic and steric factors can influence the regiochemical outcome of indazole N
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Published 02 Aug 2021

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

  • Jana M. Boysen,
  • Nauman Saeed and
  • Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

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  • and the 3-keto group are crucial for its antibacterial activity whereas, acetylation of the C-6 hydroxy group reduces the activity of HA [169]. Previous studies have also shown the antitrypanosomal, antifungal and cilioinhibitory properties of HA [72][83][86][87][88]. For these properties and little
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Published 28 Jul 2021

A systems-based framework to computationally describe putative transcription factors and signaling pathways regulating glycan biosynthesis

  • Theodore Groth,
  • Rudiyanto Gunawan and
  • Sriram Neelamegham

Beilstein J. Org. Chem. 2021, 17, 1712–1724, doi:10.3762/bjoc.17.119

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  • acetylation, methylation, and phosphorylation, which alter TF access; and iii) methylation of CpG islands in promoter regions that inhibit gene expression [4][5]. There are currently several isolated studies of TF–glycogene interactions, but a systematic “systems-level analysis” is absent. Many of these
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Published 22 Jul 2021

Chemical synthesis of C6-tetrazole ᴅ-mannose building blocks and access to a bioisostere of mannuronic acid 1-phosphate

  • Eleni Dimitriou and
  • Gavin J. Miller

Beilstein J. Org. Chem. 2021, 17, 1527–1532, doi:10.3762/bjoc.17.110

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  • is widely used as a gelling agent [1][2][3][4][5]. Detailed consideration of the alginate sub-structure indicates non-uniform proportions of M and G units (and their homo- or heteropolymeric block-groupings) which, alongside acetylation of M residues, presents a structurally heterogeneous
  • constituent M and G residues and C2/C3 acetylation for one M residue. b) Introduction of bioisosteric carboxylate groups at C6 within a ᴅ-manno thioglycoside donor, P = appropriate protecting group. a) H2N(CH2)2CN, PyBOP, DIPEA, CH2Cl2, 0 °C, 40 min, 47% (+44% 3); b) TBSOTf, imidazole, DMAP, DMF, 24 h, 80%; c
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Published 05 Jul 2021

Double-headed nucleosides: Synthesis and applications

  • Vineet Verma,
  • Jyotirmoy Maity,
  • Vipin K. Maikhuri,
  • Ritika Sharma,
  • Himal K. Ganguly and
  • Ashok K. Prasad

Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98

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  • the nucleobases with propargyl bromide in the presence of K2CO3. Nucleoside 94 was synthesized from thymidine (93) which was first tritylated at the C-5′ primary hydroxy position followed by acetylation at the C-3′ secondary hydroxy group [61]. Next, detritylation and tosylation of the protected
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Published 08 Jun 2021
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