Potential of acylated peptides to target the influenza A virus

• Daniel Lauster,
• Damian Pawolski,
• Julian Storm,
• Kai Ludwig,
• Rudolf Volkmer,
• Henry Memczak,
• Andreas Herrmann and
• Sumati Bhatia

Beilstein J. Org. Chem. 2015, 11, 589–595, doi:10.3762/bjoc.11.65

• of antiviral peptides by respective nanostructures will be perturbed or even inhibited. In conclusion, the acylation of those peptides as used in our study, and in previous studies does not resemble an advantage over other strategies of multivalent presentations. Volume size distribution profile of

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• -catalyzed ECA reactions During the early development of CA reactions, Grignard reagents were initially studied as potential nucleophiles for these reactions. Unfortunately, mixtures of the 1,4-addition and the acylation products were formed. Upon further investigation, it was discovered that the use of

• 1,4-addition of aryl amines to N-alkenoyloxazolidinones [244]. In that report, they sometimes obtained a mixture of products, where one was the desired 1,4-addition product and the other product resulted from the 1,4-addition and acylation of the amine (Scheme 35). The side product was formed in

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• -dihydroxyphenylalanine (DOPA), many O-acyl side-chain derivatives are directly accessible via a particularly expedient and scalable method not commonly applied until recently. Direct acylation of unprotected hydroxyamino acids with acyl halides or carboxylic anhydrides under appropriately acidic reaction conditions

• renders possible chemoselective O-acylation, furnishing the corresponding side-chain esters directly, on multigram-scale, in a single step, and without chromatographic purification. Assuming a certain degree of stability under acidic reaction conditions, the method is also applicable for a number of

• more elaborate procedures for chemoselective O-acylation reactions, spur its further development, and finally to chronicle the informative, but poorly documented history of its development. Keywords: amino alcohols; chemoselectivity; DOPA; hydroxyamino acids; hydroxyproline; O-acylation

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

•  7). Compounds 30–34 were obtained through Friedel–Crafts acylation of 29 with corresponding acyl chlorides in 55–81% yield. Subsequent alkylation with geranyl bromide gave products 35–39 in moderate yields from 55 to 60%. Finally, p-toluenesulfonic acid (pTSA)-catalyzed cyclization afforded the

• target compounds 40 and 41 in 53 and 65% yield, respectively. The synthesis of the second series is shown in Scheme 8 [59]. Amberlyst 15 efficiently catalyzed the condensation of 1,3,5-trihydroxybenzene (29) with isoprene in 53% yield. The following Friedel–Crafts acylation gave the intermediates 43–46

• inhibited angiogenic processes in various in vitro and in vivo models [82][83]. The typical synthesis of genistein starts from 1,3,5-trihydroxybenzene (29, Scheme 10) [84]. After the Houben–Hoesch reaction or Friedel–Crafts acylation, the cyclization of the resulting hydroxyketone 59 in the presence of BF3

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• the presence of the Pd(OAc)2/PhI(OAc)2 system in a AcOH/Ac2O mixture affords products 103 (Scheme 22) [56]. The acylation of oxime 101 and the C–H acetoxylation of 102 are performed as a one-pot operation. In the acetoxylation of alkyl groups, the methyl group is more reactive than the methylene one

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• resolution of (±)-3 by using both Novozym 435 and Lipozyme TL IM preparations in the next optimization stages. Solvent effect on kinetic resolution of (±)-3 The next stage of enzymatic analytical scale studies was designed to find the most suitable co-solvent system for the enantioselective O-acylation of

• )-(+)-5 with excellent enantiomeric excess (>99% ee) are even better. It is obvious that since methyl tert-butyl ether is free from dangerous peroxides, hence it was chosen for further optimization studies concerning Novozym 435 lipase. In turn, while investigating the acylation of (±)-3 catalyzed by

• researches have been performed to explain the influence of the acyl group donor type on the lipase-catalyzed acylation of alcohols. Amongst the wide range of this reagent type, enol esters (i.e., vinyl acetate, isopropenyl acetate), activated esters (i.e., trifluoroethyl butyrate, S-ethyl thiooctanoate), non

Linear-g-hyperbranched and cyclodextrin-based amphiphilic block copolymer as a multifunctional nanocarrier

• Yamei Zhao,
• Wei Tian,
• Guang Yang and
• Xiaodong Fan

Beilstein J. Org. Chem. 2014, 10, 2696–2703, doi:10.3762/bjoc.10.284

• acylation reaction (Scheme S1). As illustrated in Supporting Information File 1, Scheme S1, the PHEMA-based macro chain transfer agent (PHEMA-macroCTA) carrying abundant hydroxy groups was prepared by using S,S’-bis(α,α’-dimethylacetic acid) trithiocarbonate (BDATTC) as a highly efficient chain transfer

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

• Amjid Iqbal,
• El-Habib Sahraoui and
• Finian J. Leeper

Beilstein J. Org. Chem. 2014, 10, 2580–2585, doi:10.3762/bjoc.10.270

• synthesis of a furan-based analogue of thiamine. This analogue was converted to its diphosphate, which is another extremely potent inhibitor of ZmPDC, and could also be functionalised at the 2-position using a Friedel–Crafts acylation. Results and Discussion Synthesis of ThDP analogue 17 The key step in our

• -5a) to the furan carbon that has a hydrogen attached (C-4). This selective acylation of C-2 will allow the addition of substituents at this position that match the substituents in the enzymic reactions, such as the 2-hydroxyethyl group found in HEThDP (Scheme 1). Inhibition of pyruvate decarboxylase

Superoxide chemistry revisited: synthesis of tetrachloro-substituted methylenenortricyclenes

• Basavaraj M. Budanur and
• Faiz Ahmed Khan

Beilstein J. Org. Chem. 2014, 10, 2531–2538, doi:10.3762/bjoc.10.264

• -di-tert-butyl-4-methylphenol) improved the yields of methylenenortricyclenes. A complete deuterium incorporation was observed in the superoxide-mediated reaction in DMSO-d6. Friedel–Crafts acylation reactions of 3-methylenenorticyclenes yielded 2-propanone-substituted pentachloronorbornenes

• . Keywords: BHT; dehydrohalogenation/rearrangement; Friedel–Crafts acylation; methylenenortricyclene; superoxide ion; Introduction The chemistry of the superoxide ion (O2−·) has been a subject of growing interest because of its presence in all aerobic organisms as a respiratory intermediate [1][2][3][4][5

• undergoes an unexpected rearrangement by adding onto the double bond possessing the vicinal chlorines [8] and the resulting carbanion is protonated by the solvent DMSO to afford the nortricyclene 5. In the next part of our study, we have investigated the acylation reactions as it was reported that acylation

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• -cyclohexanedione (40), which was converted to isobutyl vinylogous ether 41 under acid promotion (Scheme 9) [65]. The β-ketoester 42 was prepared using a two-step sequence of acylation and alkylation, then treated with the (S)-t-Bu-PHOX catalyst system (with [Pd(dmdba)2]) to generate (+)-43 in 86% ee. The challenge

Solution phase synthesis of short oligoribonucleotides on a precipitative tetrapodal support

• Alejandro Gimenez Molina,
• Amit M. Jabgunde,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2014, 10, 2279–2285, doi:10.3762/bjoc.10.237

• this was then used for the 3'-O-acylation of 4a in pyridine in the presence of 4-dimethylaminopyridine. Experimental details for the preparation of all the building blocks and NMR and MS data for their characterization are given in Supporting Information File 1. Oligonucleotide synthesis Previously

(CF₃CO)₂O/CF₃SO₃H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

• JungKeun Kim,
• Elvira Shokova,
• Victor Tafeenko and
• Vladimir Kovalev

Beilstein J. Org. Chem. 2014, 10, 2270–2278, doi:10.3762/bjoc.10.236

• acids and aromatic ketones in TFAA/TfOH system is described. When the β-phenylpropionic acids were used as starting materials, they initially gave 1-indanones and then underwent further acylation with the formation of 2-(β-phenylpropionyl)-1-indanones as the main reaction products. In addition, the

• condensation, which comprises the C-acylation of the α-position of ketones in the form of their metal enolates, enamines or silyl ethers, with or without a catalyst. To appear as an acylating agent one of the following compounds could be required: acyl halides and acid esters, including formates and oxalates

• (2а), which was initially formed as the result of an intramolecular cyclization of 1a, underwent a further acylation with the formation of 1,3-diketone 3a. In contrast, γ-phenylbutanoic acid (1c) was quantitatively transformed only to the tetralone 2с (Table 1, entries 10 and 11). The acid-catalyzed

Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions

• Anne-Katrin Späte,
• Verena F. Schart,
• Julia Häfner,
• Andrea Niederwieser,
• Thomas U. Mayer and
• Valentin Wittmann

Beilstein J. Org. Chem. 2014, 10, 2235–2242, doi:10.3762/bjoc.10.232

• significantly higher fluorescence staining of cell-surface glycoconjugates, Ac4GlcNCyoc (1) gave higher labeling efficiency with protein preparations containing also intracellular proteins, possibly by targeting O-GlcN-acylated proteins. Since O-GlcN-acylation of proteins is associated with numerous crucial

De novo macrolide–glycolipid macrolactone hybrids: Synthesis, structure and antibiotic activity of carbohydrate-fused macrocycles

• Richard T. Desmond,
• Anniefer N. Magpusao,
• Chris Lorenc,
• Jeremy B. Alverson,
• Nigel Priestley and
• Mark W. Peczuh

Beilstein J. Org. Chem. 2014, 10, 2215–2221, doi:10.3762/bjoc.10.229

• remainder of the synthesis separately. Transacetalization of the C4,C6-O-benzylidene protecting group in methanol provided diols 9a and 9b, respectively in nearly quantitative yields. Chemoselective, DCC-mediated acylation of the primary alcohol group of 9a and 9b at 0 °C with pentenoic acid gave 10a (58

• group. This was possible by virtue of the original C4,C6 diol 9a; chemoselective acylation of the primary alcohol (C6’) unit left the C4’ alcohol available for additional reactions. Analogs were prepared under precedented conditions to give 11–16 in good yields. Analog 17, which contains a saturated

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

• Bradley D. Rose,
• Peter J. Santa Maria,
• Aaron G. Fix,
• Chris L. Vonnegut,
• Lev N. Zakharov,
• Sean R. Parkin and
• Michael M. Haley

Beilstein J. Org. Chem. 2014, 10, 2122–2130, doi:10.3762/bjoc.10.219

• Kitamura gave tetrahalide 12 in good yield on >10 g scale [25]. Suzuki cross-coupling with 12 furnished p-terphenyl 14, followed by oxidation of the methyl groups to produce diacid 15. Intramolecular Friedel–Crafts acylation then afforded 5,11-dibromo-IF-dione 11. The yields for the Sonogashira cross

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

P(O)R₂-directed Pd-catalyzed C–H functionalization of biaryl derivatives to synthesize chiral phosphorous ligands

• Rong-Bin Hu,
• Hong-Li Wang,
• Hong-Yu Zhang,
• Heng Zhang,
• Yan-Na Ma and
• Shang-dong Yang

Beilstein J. Org. Chem. 2014, 10, 2071–2076, doi:10.3762/bjoc.10.215

• group: The reactions of alkenylation, acetoxylation, hydroxylation and acylation occurred smoothly. Even if the products were obtained in low to moderate yields, they were optically pure (Figure 1, 2c–f). For the substrate of 4-methoxy substituted binaphthyl, we could achieve the alkenylation product 2g

• yields were not very high in these processes, the starting materials were completely converted except for the acylation reaction, presumably due to partial decomposition of the starting materials. These functionalized products showed that the axially chiral substrates could be well maintained in our

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• with Friedel–Crafts acylation of 1-methoxynaphthalene (11) yielding 1-acetyl-4-methoxynaphthalene (12, 73%). α-Bromination with copper(II) bromide gave 13 (44%) which was converted to the phosphate ester using tetramethylammonium diethyl phosphate in dimethoxyethane (DME) at room temperature to give

• -yl)-2-oxoethyl phosphate (24) was synthesized from 8-hydroxyquinoline (19) by first performing acylation [23] with acetyl chloride and then quantitatively protecting the hydroxy group as its benzyl ether [24] followed by installation of ketal protection with iodobenzene diacetate in alkaline methanol

Pyrrolidine nucleotide analogs with a tunable conformation

• Lenka Poštová Slavětínská,
• Dominik Rejman and
• Radek Pohl

Beilstein J. Org. Chem. 2014, 10, 1967–1980, doi:10.3762/bjoc.10.205

• 7–14 were investigated by means of NMR and molecular modeling. The effect of the relative configuration of hydroxy and nucleobase substituents as well as the effect of the alkylation or acylation of the pyrrolidine nitrogen atom on the conformation of the pyrrolidine ring were studied. The results

• of a conformational analysis show that the alkylation/acylation can be effectively used for tuning the pyrrolidine conformation over the whole pseudorotation cycle. Keywords: conformation; NMR; nucleic acids; nucleotide analog; phosphonic acid; pseudorotation; pyrrolidine; Introduction Nucleotides

• attachment to the pyrrolidine ring. Particularly, we show that the alkylation or acylation (an amine or an amide bond formation) of the pyrrolidine nitrogen atom can be used for a simple but effective tuning of pyrrolidine-ring conformation in compounds 7–14. Results and Discussion Chemistry Phosphonomethyl

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• achieved by ozonolysis to give an aldehyde, selective reduction of the latter with 9-BBN, and protection of the obtained primary alcohol as its TBS ether. N-Deprotection to give 120 was followed by acylation with benzyloxalyl chloride and treatment with triethylphosphite at elevated temperature to yield

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

• wider application for the convenient acylation of Fmoc-lysine. Synthesis of azide functionalized J8 B cell epitope (N3-J8) The conserved C-terminal region of the M protein adopts an α-helical secondary structure [13]. In order to maintain this native secondary structure, the J8 epitope (QAEDKVKQ

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• amino group stabilizing the σ-complex formed during the electrophilic attack at the C-8 carbon atom. Since the attempted acylation of the guanine amino group of 8 did not succeeded in the formation of the C-7-substituted guanosine 10, the compound was obtained in three steps from derivative 7b by

• conventional deprotection and acylation steps afforded the intermediate 34. Upon treatment with 6 N HCl at 80 °C for 2 h the 3-(3-amino-3-carboxypropyl)uridine (35) was obtained in 80% yield. While this nucleoside was found in some transfer RNAs, no details of its application were disclosed. Boehm and

• irradiation conditions with the substrates adsorbed onto Montmorillonite K-10 clay (Scheme 45) [122]. The formation of compounds 110 proceeded via: (a) N-acylation of aminosugar by the anthranilic acid derivative, and (b) N-acylation of the resulting amide at the aromatic amino group by benzoic acid (or 4

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• with classical organic acylation reactions (Friedel–Crafts reaction, esterification, amide synthesis, Scheme 1). Some of these complexes have been used as organometallic gelators [19][20], as a novel class of cytostatic compounds [26], and catalysts for unusual radical cyclizations [27][28][29][30][31

• acid chlorides. Typical results are summarized in Table 1. Gratifyingly, the acylation reactions proceed without problems and the azide-functionalized titanocenes can generally be obtained in good yields after 16 h. The somewhat lower yields obtained with carboxylate 3 are probably due to an increased

• ] cyclizations [56][57][58]. Carboxylates employed as titanocene starting materials for azide-substituted complexes. Azides employed in this study and conditions for their synthesis. Most active titanocenes of this study and their AC50 values. Modular titanocene synthesis via acylation reactions [24]. Synthesis

The search for new amphiphiles: synthesis of a modular, high-throughput library

• George C. Feast,
• Thomas Lepitre,
• Xavier Mulet,
• Charlotte E. Conn,
• Oliver E. Hutt,
• G. Paul Savage and
• Calum J. Drummond

Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163

• the diol prior to acylation [32]. For the triple-chained tails, triol 15 was synthesised from tris(hydroxymethyl)methylamine (TRIS) and 4-pentynoic acid using ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), following a similar method to Pucci et al. (Scheme 2) [33]. TRIS has been used previously

Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction

• Marina Rubina,
• William M. Sherrill,
• Alexey Yu. Barkov and
• Michael Rubin

Beilstein J. Org. Chem. 2014, 10, 1536–1548, doi:10.3762/bjoc.10.158

• into acyl chloride (S)-16. Subsequent acylation of (R)-phenylglycinol with (S)-16 afforded amide 17, which was subjected to cyclization in the presence of mesyl chloride and a base providing dihydrooxazole 18. Diastereoselective partial reduction of the dibromocyclopropane moiety with zinc dust in