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

Convergent synthesis of the tetrasaccharide repeating unit of the O-antigen of Shigella boydii type 9

• Abhishek Santra and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2011, 7, 1182–1188, doi:10.3762/bjoc.7.137

• (br s, H-1C), 4.95 (d, J = 3.6 Hz, H-1D) in the 1H NMR and signals at δ 92.8 (C-1D), 81.0 (C-1C) in the 13C NMR spectrum). Compound 6 was transformed into disaccharide thioglycoside donor 7 in 91% yield under a one-pot deacetylation–benzylation reaction condition [22] (Scheme 2). In this case, the

• subjected to a reaction sequence involving (a) deacetylation using 0.1 M sodium methoxide in methanol; (b) TEMPO mediated selective oxidation [27][28][29] of the primary hydroxy group leaving secondary hydroxy groups unaffected in a phase transfer reaction condition and (c) removal of benzyl groups for

Amine-linked diglycosides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays

• Ian Cumpstey,
• Jens Frigell,
• Elias Pershagen,
• Tashfeen Akhtar,
• Elena Moreno-Clavijo,
• Inmaculada Robina,
• Dominic S. Alonzi and
• Terry D. Butters

Beilstein J. Org. Chem. 2011, 7, 1115–1123, doi:10.3762/bjoc.7.128

• unsaturated glycoside 4 to be achieved; phosphomolybdic acid [32] gave the product (α:β, 8:1) in 63% yield. Deacetylation of 4 and regioselective silylation of the primary alcohol gave the threo allylic alcohol 2. The sulfonamide nucleophiles 6, 7 and 9 were prepared from the corresponding amines 5 [33] and 8

Synthesis, reactivity and biological activity of 5-alkoxymethyluracil analogues

• Lucie Brulikova and
• Jan Hlavac

Beilstein J. Org. Chem. 2011, 7, 678–698, doi:10.3762/bjoc.7.80

• 84 was prepared by a previously described procedure [23]. Next 5-bromovinyluracil (BVUr) was silylated and reacted with 84 in the presence of TMSOTf as the Lewis acid. This was followed by deacetylation with anhydrous K2CO3 in MeOH to provide the di-O-benzylated nucleoside 85 in 73% yield. For the

Synthesis of glycoconjugate fragments of mycobacterial phosphatidylinositol mannosides and lipomannan

• Benjamin Cao,
• Jonathan M. White and
• Spencer J. Williams

Beilstein J. Org. Chem. 2011, 7, 369–377, doi:10.3762/bjoc.7.47

• catalytic NaOMe in MeOH/CH2Cl2 provided 1 and 2 in yields of 99% and 94%, respectively. Our strategy towards the synthesis of the trisaccharide 3 sought to utilize a glycosyl donor possessing a 2-O-acetyl group with benzoyl groups at the remaining positions, anticipating that selective deacetylation post

• outcome was obtained using NIS/TfOH activation of thioglycoside donor 17 to furnish disaccharide 26 in 72% yield. Selective deacetylation of 26 was achieved by acidic transesterification using 3% AcCl in MeOH/CH2Cl2 to give the secondary alcohol 27 in 73% yield. Mannosylation of 27 using donor 21 under

Bioorthogonal metabolic glycoengineering of human larynx carcinoma (HEp-2) cells targeting sialic acid

• Arne Homann,
• Riaz-ul Qamar,
• Sevnur Serim,
• Petra Dersch and
• Jürgen Seibel

Beilstein J. Org. Chem. 2010, 6, No. 24, doi:10.3762/bjoc.6.24

• with HEp-2 cells. Ac4GlcNAz 16 is believed to enter the cell by diffusion through the membrane, to undergo deacetylation in the cytoplasm and then incorporated into the cell surface glycoproteins and glycolipids. Alternatively, it is metabolically converted to Neu5Az [14]. Neu5Hex may enter the cell by

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• hydrochloride and subsequent deacetylation (Scheme 6). Structural and conformational studies on 50 were carried out by NMR, which showed that the structure was stabilised by two anti-parallel seven-membered ring intramolecular hydrogen bonds, resulting in relatively high rotational barriers for the Z,E:E,Z/E

Convergent syntheses of Le^X analogues

• An Wang,
• Jenifer Hendel and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2010, 6, No. 17, doi:10.3762/bjoc.6.17

• (NaN3, DMF, 80 °C) gave the known [46] 6-azidohexyl glycoside 15 quantitatively. Zemplén deacetylation of triacetate 15 followed by conversion of the triol to the 4,6-benzylidene acetal (16) and then chloroacetylation at O-3 gave intermediate 17 that was submitted to reductive opening of the benzylidene

• group (NaCNBH3, HCl·Et2O) to yield acceptor 6. The triacetate 15 was also converted in seven steps to acceptor 5. The phthalimido group was first removed (ethylenediamine, EtOH) and the free amine acetylated. Zemplén deacetylation was followed by conversion of the triol to the 4,6-benzylidene acetal 18

• well as to some deacetylation of the galactose residue. Thus, after acetylation of the crude product, the desired 6-benzylthiohexyl trisaccharide 32 was isolated in excellent yield (Scheme 3). It is important to point out that the 6-chlorohexyl glycoside 29 and the 6-benzylthiohexyl glycoside 32 co

Synthesis of densely functionalized enantiopure indolizidines by ring- closing metathesis (RCM) of hydroxylamines from carbohydrate- derived nitrones

• Marco Bonanni,
• Marco Marradi,
• Francesca Cardona,
• Stefano Cicchi and
• Andrea Goti

Beilstein J. Org. Chem. 2007, 3, No. 44, doi:10.1186/1860-5397-3-44

• this reason the crude reaction mixtures were directly employed in the following steps. Identity of compounds 12 and 13 was firmly established after their transformation into the corresponding amines and further elaboration. After deacetylation with KHCO3, in situ reduction of the N-O bond with zinc

2-Arylhydrazononitriles as building blocks in heterocyclic synthesis: A novel route to 2-substituted- 1,2,3-triazoles and 1,2,3-triazolo[4,5-b]pyridines

• Saleh M. Al-Mousawi and
• Moustafa Sh. Moustafa

Beilstein J. Org. Chem. 2007, 3, No. 12, doi:10.1186/1860-5397-3-12

• . [15] Compound 9 was coupled with benzenediazonium chloride most likely through the intermediate 11a. The latter intermediate cyclized into 11b. Deacetylation of 11b followed by hydrogen shift produced 10. This again confirms that the acetyl and the amino functions in cyclization product are adjacent

8-epi-Salvinorin B: crystal structure and affinity at the κ opioid receptor

• Thomas A. Munro,
• Katharine K. Duncan,
• Richard J. Staples,
• Wei Xu,
• Lee-Yuan Liu-Chen,
• Cécile Béguin,
• William A. Carlezon Jr. and
• Bruce M. Cohen

Beilstein J. Org. Chem. 2007, 3, No. 1, doi:10.1186/1860-5397-3-1

• -salvinorin A (1b).[12] Brown also reported that deacetylation of 1a under basic conditions gave 8-epi-salvinorin B (2b), but did not characterize either compound. Several further reports of epimerization at C-8 appeared over the following decade, [13][14] but no characterization data was presented. Valdés