Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

• Christopher Albler,
• Ralph Hollaus,
• Hanspeter Kählig and
• Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

• azide reduction followed by final deacetylation using methanolic sodium methoxide furnishes the title compounds. Keywords: allylation; carbohydrates; epoxidation; indium; multivalent glycosystems; organocatalysis; Introduction The indium-mediated allylation of carbonyl compounds has proven to be a

• . Deacetylation in a methanolic HCl solution proved to be most efficient and the subsequent ozonolysis generated sugar azides 6a–c (Scheme 2). It turned out to be essential to perform the acidic acetate cleavage of compounds 5a–c under strictly dry conditions, since even small amounts of water promoted an

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

• Meriem Smadhi,
• Sophie de Bentzmann,
• Anne Imberty,
• Marc Gingras,
• Raoudha Abderrahim and
• Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

• (propargylthio)triazine 2, using CuI and diisopropylethylamine (DIPEA) in DMF under microwave irradiation at 110 °C for 15 min. It provided the peracetylated D-galactopyanosyl cluster 9 in 73% yield. The peracetyl D-glucopyranosyl cluster 10 was similarly obtained in 92% yield. The deacetylation of the

Convergent synthetic methodology for the construction of self-adjuvanting lipopeptide vaccines using a novel carbohydrate scaffold

• Vincent Fagan,
• Istvan Toth and
• Pavla Simerska

Beilstein J. Org. Chem. 2014, 10, 1741–1748, doi:10.3762/bjoc.10.181

• 4 and conversion to the desired glycosylation product 5. The presence of unreacted hydroxy ester 3 made purification of glycosylation product 5 difficult. Therefore, the crude reaction mixture was subjected to Zemplén deacetylation [24] to give intermediate 6, and the unreacted hydroxy ester 3 was

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• dipolarophile-on-the-sugar approach [44]. The deprotection of compounds 9 and 13 from the acetyl groups was carried out by a transesterification reaction in the presence of CH3ONa in CH3OH at room temperature according to the standard Zemplén procedure. Complete deacetylation was achieved in 1 hour, as

• (150 W, 80 °C) facilitated the complete tetra-functionalization in only 40 minutes. Subsequent deacetylation with the Zemplén method led to target compounds 3 and 4, both of which were characterized by 1D and 2D NMR techniques and ESIMS analyses. Gal-3/glycocalixarenes interaction studies by SPR His6

Multivalent scaffolds induce galectin-3 aggregation into nanoparticles

• Candace K. Goodman,
• Mark L. Wolfenden,
• Pratima Nangia-Makker,
• Anna K. Michel,
• Avraham Raz and
• Mary J. Cloninger

Beilstein J. Org. Chem. 2014, 10, 1570–1577, doi:10.3762/bjoc.10.162

• and the changes in Mw upon deacetylation, enabling characterization of the average number of sugars per dendrimer [30]. Additional characterization details (including 1H NMR spectra) are provided in Supporting Information File 1. Characterization of dendrimer/galectin-3 aggregates Dynamic light

• mg, 2.20 μmol) solution. The mixture was stirred for 8 h at which point a 75 μL aliquot was collected and lyophilized for MALDI–TOF and NMR analysis. The remainder of the reaction mixture was lyophilized and subjected to the deacetylation procedure. This procedure for carbohydrate functionalization

• procedure for deacetylation to afford lactose-functionalized dendrimers To the lyophilized solid per-O-acetylated dendrimers, 1 mL of 1:1 water/methanol was added, at which point the dendrimer became a white precipitate. To this mixture was added 0.2 equiv of NaOMe (0.8 M in MeOH) for each peripheral

Design, automated synthesis and immunological evaluation of NOD2-ligand–antigen conjugates

• Marian M. J. H. P. Willems,
• Gijs G. Zom,
• Nico Meeuwenoord,
• Ferry A. Ossendorp,
• Herman S. Overkleeft,
• Gijsbert A. van der Marel,
• Jeroen D. C. Codée and
• Dmitri V. Filippov

Beilstein J. Org. Chem. 2014, 10, 1445–1453, doi:10.3762/bjoc.10.148

• attached to the anomeric center of the glucosamine moiety using oxazoline 6 [37][38][39]. Deacetylation and subsequent installation of the benzylidene protective group then gave alcohol 9. Coupling of 9 with (S)-2-chloropropanoic acid in the presence of sodium hydride resulted in the formation of protected

Synthesis of the first examples of iminosugar clusters based on cyclopeptoid cores

• Mathieu L. Lepage,
• Alessandra Meli,
• Anne Bodlenner,
• Céline Tarnus,
• Francesco De Riccardis,
• Irene Izzo and
• Philippe Compain

Beilstein J. Org. Chem. 2014, 10, 1406–1412, doi:10.3762/bjoc.10.144

• picrate to 9a indeed dramatically simplified the 1H NMR spectrum by inducing the formation of a sodium complex with a 6-fold symmetry (Figure 2ii). Subsequent O-deacetylation of compounds 9 using anion exchange Amberlite IRA-400 (OH−) resin provided the final deprotected iminosugar clusters 10 in high

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• formanilide (R = H) or chloroacetanilide (R = CH2Cl) as a substrate (Scheme 10) produced the expected phosphoramidate by a mechanism which simultaneously involved deacetylation. The higher reactivity of formanilide and chloroacetanilide, when compared to aniline, was explained by the higher acidity of the

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• /trans-isomer in the mixture from 1:4 to 1:2. Deacetylation of cis-23-O-acetylsilybins All pure cis-silybins were obtained as their C-23 acetates. The deacetylation proved to be rather difficult, as both acidic and basic hydrolysis as well as mild transesterification (NaOMe, MeOH) failed and/or resulted

Efficient carbon-Ferrier rearrangement on glycals mediated by ceric ammonium nitrate: Application to the synthesis of 2-deoxy-2-amino-C-glycoside

• Alafia A. Ansari,
• Y. Suman Reddy and
• Yashwant D. Vankar

Beilstein J. Org. Chem. 2014, 10, 300–306, doi:10.3762/bjoc.10.27

• subjected to deacetylation by using K2CO3/MeOH (Scheme 2) followed by the selective protection of the primary hydroxy group as a benzyl ether by using Bu2SnO and benzyl bromide in the presence of triethylamine and tetrabutylammonium iodide to afford alcohol 8 in 69% yield over 2 steps. The terminal olefin

Studies toward bivalent κ opioids derived from salvinorin A: heteromethylation of the furan ring reduces affinity

• Thomas A. Munro,
• Wei Xu,
• Douglas M. Ho,
• Lee-Yuan Liu-Chen and
• Bruce M. Cohen

Beilstein J. Org. Chem. 2013, 9, 2916–2924, doi:10.3762/bjoc.9.328

• chromatography, blocking the column. This was therefore extracted from the crude product with hot water. Our results conflict with a previous report that heating 1 in acetic acid led to deacetylation and epimerization [29]. In our hands, 1 was freely soluble in glacial acetic acid and was recovered unchanged

Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C₂-symmetric building block: a strategy for the synthesis of decanolide natural products

• Bernd Schmidt and
• Oliver Kunz

Beilstein J. Org. Chem. 2013, 9, 2544–2555, doi:10.3762/bjoc.9.289

• , resulted in the expected RCM/ring-opening sequence, but also in a partial deacetylation. For this reason, the crude reaction mixture was subsequently treated with aqueous NaOH to complete the ester cleavage, giving the macrolactonization precursor 29 [31] in 81% yield (Scheme 6). In a previous study [24

Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives

• Paola Bonaccorsi,
• Maria Luisa Di Gioia,
• Antonella Leggio,
• Lucio Minuti,
• Teresa Papalia,
• Carlo Siciliano,
• Andrea Temperini and
• Anna Barattucci

Beilstein J. Org. Chem. 2013, 9, 2410–2416, doi:10.3762/bjoc.9.278

• obtained by the almost quantitative deacetylation of 2,3,4,6-tetraacetyl-2-propyn-1-yl-β-D-glucopyranoside (4). Firstly, we proceeded with the setup of the click cycloaddition between triptycene hexa-azide 3 and 2,3,4,6-tetraacetyl-1-prop-2-ynyl-β-D-glucopyranoside (4). We attempted to perform the reaction

• triptycene (1). Synthesis of six-armed triptycene azide 3. Synthesis of six-armed triptycene derivatives 8–10 from triptycene azide 3. aNot easily isolable in pure form (see Results and Discussion section, last paragraph). Deacetylation of target compounds 8 and 9 to 10 and 11, respectively. Supporting

A simple, enaminone-based approach to some bicyclic pyridazinium tetrafluoroborates

• František Josefík,
• Markéta Svobodová,
• Valerio Bertolasi and
• Petr Šimůnek

Beilstein J. Org. Chem. 2013, 9, 1463–1471, doi:10.3762/bjoc.9.166

• Enaminones 3 were prepared as previously reported [12] (Scheme 3). The last step of the synthesis is the deacetylation of 7 by sodium in ethanol. In the case of substrate 3a the deacetylation spontaneously takes place during the 2nd step. The reaction of the enaminone 3a with two equivalents of 4

Design and synthesis of tag-free photoprobes for the identification of the molecular target for CCG-1423, a novel inhibitor of the Rho/MKL1/SRF signaling pathway

• Jessica L. Bell,
• Andrew J. Haak,
• Susan M. Wade,
• Yihan Sun,
• Richard R. Neubig and
• Scott D. Larsen

Beilstein J. Org. Chem. 2013, 9, 966–973, doi:10.3762/bjoc.9.111

• began with the acetylation of 4-chloro-3-nitroaniline (9) followed by reduction of the nitro group using iron and hydrochloric acid to generate aniline 10. The azido group was introduced by diazotization/azidation to provide 11. Deacetylation with potassium hydroxide revealed aniline 12, which was then

A new synthetic access to 2-N-(glycosyl)thiosemicarbazides from 3-N-(glycosyl)oxadiazolinethiones and the regioselectivity of the glycosylation of their oxadiazolinethione precursors

• El Sayed H. El Ashry,
• El Sayed H. El Tamany,
• Mohy El Din Abdel Fattah,
• Mohamed R. E. Aly,
• Ahmed T. A. Boraei and
• Axel Duerkop

Beilstein J. Org. Chem. 2013, 9, 135–146, doi:10.3762/bjoc.9.16

• absorption bands that do not appear in the IR spectra of their precursors. Finally, the 13C NMR spectra of 11–13 show signals for NC=O groups at δC 159.40–162.90 ppm in addition to the NC=S groups at δC 183.10–184.50 ppm. Deacetylation of 10 is only confined to the O-acetyl groups, but the N-acetyl group

Thioester derivatives of the natural product psammaplin A as potent histone deacetylase inhibitors

• Matthias G. J. Baud,
• Thomas Leiser,
• Vanessa Petrucci,
• Mekala Gunaratnam,
• Stephen Neidle,
• Franz-Josef Meyer-Almes and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2013, 9, 81–88, doi:10.3762/bjoc.9.11

• epigenetic modifications, their biological outcomes, and how their misregulation is involved in diseases such as cancer [1][2]. The dynamic post-translational acetylation/deacetylation of histone proteins is one of the most commonly studied epigenetic events, and occurs at specific lysine residues on the N

• -terminal histone tails, which project out from the nucleosome (the fundamental repeating unit of chromatin). Acetylation/deacetylation of such lysine residues is achieved by the action of histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively. Histone deacetylation by HDACs causes

Automated synthesis of sialylated oligosaccharides

• Davide Esposito,
• Mattan Hurevich,
• Bastien Castagner,
• Cheng-Chung Wang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 1601–1609, doi:10.3762/bjoc.8.183

• with a benzoyl group at the C3 hydroxy position resulted in a lower glycosylation yield (36%), suggesting that an ester can lower the nucleophilicity of the vicinal C4-hydroxy. The synthesis was completed by deacetylation of compound 15 under Zemplén's conditions, followed by saponification and

Synthesis of compounds related to the anti-migraine drug eletriptan hydrobromide

• Suri Babu Madasu,
• Nagaji Ambabhai Vekariya,
• M. N. V. D. Hari Kiran,
• Badarinadh Gupta,
• Aminul Islam,
• Paul S. Douglas and
• Korupolu Raghu Babu

Beilstein J. Org. Chem. 2012, 8, 1400–1405, doi:10.3762/bjoc.8.162

• acetate [9] this affords (R)-1-acetyl-5-[2(phenylsulfonyl)ethyenyl]-3-(N-methylpyrrolidin-2-ylmethyl)-1H-indole (12), under Heck reaction conditions. Deacetylation of (12) by using potassium carbonate affords (R)-5-[(2-phenylsulfonyl)ethenyl]-3-(N-methylpyrrolidine-2-ylmethyl)-1H-indole (13). Reduction of

• deacetylation reaction. Eletriptan N-oxide isomers 3 and 4 are possible contaminants that can be formed by oxidation in air. These compounds were prepared by oxidation of eletriptan (14) with aqueous hydrogen peroxide (~50%, w/w) in the presence of catalytic amounts of ammonium molybdate. The isomers 3 and 4

• , the deacetylation of enesulfone derivative 12 was performed in anhydrous methanol at ambient temperature with potassium carbonate. The reaction was completed within 30 min, but the formation of eletriptan methoxy impurity 7 was high (0.20–0.70%). Moreover, after isolation and the subsequent stage, it

Synthesis of 4” manipulated Lewis X trisaccharide analogues

• Christopher J. Moore and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2012, 8, 1134–1143, doi:10.3762/bjoc.8.126

• activation of the anomeric acetate and glycosidation with trichloroethanol; and (3) Zemplén deacetylation. This sequence of reactions gave the desired galactoside 14 in 78% yield and as a 9:1 α/β mixture, as assessed by 1H NMR. It is important to point out that the second step in this sequence of reactions

Synthesis and structure of tricarbonyl(η⁶-arene)chromium complexes of phenyl and benzyl D-glycopyranosides

• Thomas Ziegler and
• Ulrich Heber

Beilstein J. Org. Chem. 2012, 8, 1059–1070, doi:10.3762/bjoc.8.118

• separation of the diastereomers by crystallization was not possible for complexes 2p and 2q. The O-acetylated carbohydrate-derived tricarbonyl(η6-arene)chromium complexes prepared here can be deprotected without affecting the chromium complex, as exemplified in Scheme 2. Zemplén deacetylation of 2c afforded

High-affinity multivalent wheat germ agglutinin ligands by one-pot click reaction

• Henning S. G. Beckmann,
• Heiko M. Möller and
• Valentin Wittmann

Beilstein J. Org. Chem. 2012, 8, 819–826, doi:10.3762/bjoc.8.91

• sample of disaccharide 1 was eluted from a silica gel column for a second time. In comparison, the use of the less polar propargyl β-D-glucoside instead of 1 in the one-pot procedure with amine A4 led to the corresponding divalent glycocluster in a yield of 86% [48]. Finally, O-deacetylation of the

• intermediate diazide 2. Deacetylation of glycoconjugates B1–B6. (a) NaOMe, MeOH. Formation of side-product 5 during the synthesis of 4. Synthesis of glycoclusters B1–B6 using the one-pot procedure for diazo transfer and azide-alkyne cycloaddition. Absolute and relative IC50 values of synthetic ligands C1–C6

Facile synthesis of nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranosides from ManNAc-oxazoline

• Karel Křenek,
• Petr Šimon,
• Lenka Weignerová,
• Barbora Fliedrová,
• Marek Kuzma and
• Vladimír Křen

Beilstein J. Org. Chem. 2012, 8, 428–432, doi:10.3762/bjoc.8.48

• 5 (22% yield) and p-nitrophenyl glycoside 6 (34% yield) in approximately 2:3 ratio, which was separated by flash chromatography. Zemplén deacetylation of 4 and 5 afforded the title compounds 7 and 8 in almost quantitative yields. Conclusion In conclusion, a simple and robust procedure for the

Acceptor-influenced and donor-tuned base-promoted glycosylation

• Stephan Boettcher,
• Martin Matwiejuk and
• Joachim Thiem

Beilstein J. Org. Chem. 2012, 8, 413–420, doi:10.3762/bjoc.8.46

• derivatives 22 and 23, a five-step synthesis was performed in each case to obtain the galacto- and glucopyranosyl donors 8 and 9 (Scheme 3). Initially, peracetates 22 and 23 were converted into the thioglycopyranosides 24 and 25 with BF3∙Et2O/thiophenole [7]. Subsequent deacetylation [8] and benzylation [9

Directed aromatic functionalization in natural-product synthesis: Fredericamycin A, nothapodytine B, and topopyrones B and D

• Charles Dylan Turner and
• Marco A. Ciufolini

Beilstein J. Org. Chem. 2011, 7, 1475–1485, doi:10.3762/bjoc.7.171

• converted into an acetate ester (Fischer-type esterification). Compound 15, a form of 4 suitable for the conduction of subsequent operations, was secured by deacetylation of 14 and Swern oxidation. Fragment 5 was best produced in the guise of compound 20, the construction of which also relied upon DAF