Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• )-protected ᴅ-serine 12 (Scheme 2). Treatment of the olefin 15 with trifluoroacetic acid (TFA) cleaved the Boc protecting group and the acetonide to deliver unsaturated amino alcohol 16. The amino group in 16 was protected by the fluorenylmethyloxycarbonyl (Fmoc) protecting group for solid-phase peptide

Asymmetric organocatalytic Michael addition of cyclopentane-1,2-dione to alkylidene oxindole

• Estelle Silm,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2022, 18, 167–173, doi:10.3762/bjoc.18.18

• ). The use of a sterically more demanding Fmoc-protecting group decreased the ee values even more for the minor diastereoisomer (Scheme 1, 3c). Surprisingly, with benzyl-protected oxindole, the reaction did not proceed (Scheme 1, 3d), which implies that the carbonyl group of the carbamate moiety in the N

First total synthesis of hoshinoamide A

• Haipin Zhou,
• Zihan Rui,
• Yiming Yang,
• Shengtao Xu,
• Yutian Shao and
• Long Liu

Beilstein J. Org. Chem. 2021, 17, 2924–2931, doi:10.3762/bjoc.17.201

• washed with MeOH (3 × 20 mL) and DCM (3 × 20 mL). Tripeptide 8 was recovered (1.6 mmol). The unreacted resin was capped with MeOH in a mixture of MeOH/DIPEA/DCM (1:2:7, 10 mL) for 5 h. The Fmoc protecting group was removed following the general procedure and the remaining amino acids were successively

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• nanostructures as well as the secondary structures. Results and Discussion Solid-phase peptide synthesis and purification The target octapeptide was synthesized in the solid phase following four steps, including: i) deprotection of the Fmoc protecting group, ii) coupling of an amino acid, iii) cleavage of the

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• ]. Considering that the widely used Fmoc protecting group, of which the H-9 has a pKa of ≈22 [42], can be readily removed with a weak base such as piperidine, we hypothesized that the oxidized Dmoc groups and linkers could be cleaved under weakly basic and non-nucleophilic conditions via β-elimination. Indeed

Novel solid-phase strategy for the synthesis of ligand-targeted fluorescent-labelled chelating peptide conjugates as a theranostic tool for cancer

• Sagnik Sengupta,
• Mena Asha Krishnan,
• Premansh Dudhe,
• Ramesh B. Reddy,
• Bishnubasu Giri,
• Sudeshna Chattopadhyay and
• Venkatesh Chelvam

Beilstein J. Org. Chem. 2018, 14, 2665–2679, doi:10.3762/bjoc.14.244

• bubbling nitrogen for 10 minutes through the swelled resin beads. The procedure was repeated thrice (1 × 4 mL; 2 × 3 mL) to ensure complete deprotection of Fmoc protecting group. General procedure for peptide cleavage from resin beads A mixture of 9.25 mL trifluoroacetic acid (TFA), 0.25 mL

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• separation of the anomeric α/β mixture furnished the anomerically pure trisaccharide 15. Next, three acyl residues were introduced at positions 2’, 3’ and 3 by successive deprotection–acylation sequence. The N-Fmoc protecting group was removed using DBU and the resulting free amino group was acylated with (R

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• obtain oligonucleotide–PEG–peptide conjugates [55][56]. The Fmoc protecting group was first removed and the peptide was assembled on the exposed amino function. Since the peptide moiety did not contain acid labile side chain protections, the oligonucleotide sequence could then be assembled by the

DNA functionalization by dynamic chemistry

• Zeynep Kanlidere,
• Oleg Jochim,
• Marta Cal and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2016, 12, 2136–2144, doi:10.3762/bjoc.12.203

• 55 °C. The Fmoc protecting group of oligonucleotide ON1 was removed, however, the cyanoethyl group as a base-labile protecting group of the thiol was not removed quantitatively from the oligonucleotide ON2 [54][55][56][57][58]. Dynamic template-driven assembly of double strand libraries

Automated glycan assembly of a S. pneumoniae serotype 3 CPS antigen

• Markus W. Weishaupt,
• Stefan Matthies,
• Mattan Hurevich,
• Claney L. Pereira,
• Heung Sik Hahm and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2016, 12, 1440–1446, doi:10.3762/bjoc.12.139

• maintained for 30 min. The temporary Fmoc protecting group was cleaved with triethylamine in DMF (N,N-dimethylformamide; 10% v/v). The Lev protecting group was removed using hydrazine monohydrate in pyridine/acetic acid (3:2 v/v). The crude oligosaccharide products were cleaved from the solid support by

Automated solid-phase synthesis of oligosaccharides containing sialic acids

• Chian-Hui Lai,
• Heung Sik Hahm,
• Chien-Fu Liang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2015, 11, 617–621, doi:10.3762/bjoc.11.69

• these considerations sialyl phosphate building blocks 4 and 5 [14] were selected for automated glycan assembly using monosaccharides (Scheme 1). The synthesis of building block 4 commenced with the placement of a C-9 Fmoc protecting group on thioglycoside 1 [14] to produce 2. Installation of O

• washing step. In addition, TMSOTf eliminates any moisture that may have resided on the resin or in the reaction vessel. Glycosylations were carried out using the optimized temperatures for each building block using twice five equivalents of building block and activator. Removal of the Fmoc protecting

• group with triethylamine uncovered the hydroxy group to serve as the nucleophile in the next coupling. Participating protecting groups at the C2 position of building blocks 6, 7, 9 and 10 ensured selective formation of β-glycosidic linkages during the glycosylations. These building blocks resulted in

Synthesis and biological evaluation of a novel MUC1 glycopeptide conjugate vaccine candidate comprising a 4’-deoxy-4’-fluoro-Thomsen–Friedenreich epitope

• Manuel Johannes,
• Maximilian Reindl,
• Bastian Gerlitzki,
• Edgar Schmitt and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2015, 11, 155–161, doi:10.3762/bjoc.11.15

• counterpart 13 to enzymatic hydrolysis using a commercially available ß-galactosidase from bovine testes [E.C. 3.2.1.23] (Figure 1). Therefore, glycosyl amino acid 11 was carefully de-O-acetylated using NaOMe in MeOH at pH 8.5 followed by re-installment of the Fmoc protecting group. After HPLC purification

Synthesis of novel conjugates of a saccharide, amino acids, nucleobase and the evaluation of their cell compatibility

• Dan Yuan,
• Xuewen Du,
• Junfeng Shi,
• Ning Zhou,
• Abdulgader Ahmed Baoum and
• Bing Xu

Beilstein J. Org. Chem. 2014, 10, 2406–2413, doi:10.3762/bjoc.10.250

• -Asp (20). After loading the first amino acid (Fmoc-Asp(Ot-Bu)-OH) on the 2-chlorotrityl chloride resin, we blocked the resin by dichloromethane (DCM)/methanol (MeOH)/N,N-diisopropylethylamine (DIEA) (8:1.5:0.5), next removed the Fmoc protecting group by 20% piperidine in N,N-dimethylformamide (DMF

Photoswitchable precision glycooligomers and their lectin binding

• Daniela Ponader,
• Sinaida Igde,
• Marko Wehle,
• Katharina Märker,
• Mark Santer,
• David Bléger and
• Laura Hartmann

Beilstein J. Org. Chem. 2014, 10, 1603–1612, doi:10.3762/bjoc.10.166

• Fmoc protecting group was cleaved by treatment with 25% piperidine in DMF three times for 5, 10 and 15 minutes. After complete removal of the Fmoc protecting group, the second building block (AZO or EDS) was coupled following the same reaction conditions. After repetition of the coupling/deprotection

• hours. After that, the resin was washed with a 23 mM solution of sodium diethyl dithiocarbamate in DMF, water, DMF and DCM. Fmoc cleavage: The Fmoc protecting group was cleaved by the addition of a solution of 25% piperidine in DMF three times for 5, 10 and 15 minutes, respectively. This was followed by

The diketopiperazine-fused tetrahydro-β-carboline scaffold as a model peptidomimetic with an unusual α-turn secondary structure

• Francesco Airaghi,
• Andrea Fiorati,
• Giordano Lesma,
• Manuele Musolino,
• Alessandro Sacchetti and
• Alessandra Silvani

Beilstein J. Org. Chem. 2013, 9, 147–154, doi:10.3762/bjoc.9.17

• in CH2Cl2 and 2,6-lutidine to give 5. The formation of the fused, tetracyclic THBC-DKP ring system was then easily achieved by removal of the N-Fmoc protecting group [49] and spontaneous lactamization to give the diketopiperazine ring of 6. The obtained compound 6 represents a valuable peptidomimetic

S-Fluorenylmethyl protection of the cysteine side chain upon N^α-Fmoc deprotection

• Johannes W. Wehner and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2012, 8, 2149–2155, doi:10.3762/bjoc.8.242

• transprotection reaction was studied. Keywords: Fmoc protecting group; glycoamino acids; N-Fmoc→S-Fm transprotection; protecting groups; Introduction In the course of our work on the synthesis of glycoamino acids, we have recently used L-cysteine as a scaffold for the synthesis of various glycoclusters [1][2][3

• ) protecting group for the synthesis of 3-dimer, we observed an unexpected but high-yielding S-fluorenylmethyl (Fm) protection of the cysteine side chain during N-Fmoc deprotection. Hence, this side reaction was further investigated under different reaction conditions and the results of this study are

• oxidiation of the cysteine moiety into the respective cystine form. Indeed, preparation of glycoamino acid derivatives such as 3-dimer, an oxidized cysteine, or cystine derivative, is facile and can be realized via different synthetic routes. However, as we employed the fluorenylmethoxycarbonyl (Fmoc

Total synthesis and biological evaluation of fluorinated cryptophycins

• Christine Weiß,
• Tobias Bogner,
• Benedikt Sammet and
• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 2060–2066, doi:10.3762/bjoc.8.231

• 28, representing units A and B was then esterified with 19 under Yamaguchi conditions with 2,4,6-trichlorobenzoylchloride and triethylamine in the presence of catalytic amounts of DMAP. Macrocyclization was brought about by cleavage of the Fmoc protecting group from the unit C amino group, which

Building photoswitchable 3,4'-AMPB peptides: Probing chemical ligation methods with reducible azobenzene thioesters

• Gehad Zeyat and
• Karola Rück-Braun

Beilstein J. Org. Chem. 2012, 8, 890–896, doi:10.3762/bjoc.8.101

• by manual Fmoc-based peptide synthesis using standard amino-acid building blocks (Scheme 2) [4]. Commercially available preloaded Wang resin was used, and HBTU was applied as the coupling reagent in the presence of DIPEA in NMP. Removal of the temporary Fmoc-protecting group was achieved by using 20

Synthesis of szentiamide, a depsipeptide from entomopathogenic Xenorhabdus szentirmaii with activity against Plasmodium falciparum

• Friederike I. Nollmann,
• Andrea Dowling,
• Marcel Kaiser,
• Klaus Deckmann,
• Sabine Grösch,
• Richard ffrench-Constant and
• Helge B. Bode

Beilstein J. Org. Chem. 2012, 8, 528–533, doi:10.3762/bjoc.8.60

• hydrochloride and DMAP together with DIC all turned out to be unsuccessful. However, we were then able to establish the ester bond in 5 using modified Yamaguchi conditions [17]. Subsequently, the Fmoc-protecting group was removed at room temperature, and the peptide was cleaved from the resin with 3

• /L) first at 0 °C then with warming to room temperature overnight. After the quantitative reaction, the Fmoc-protecting group was cleaved by using 40% piperidine in DMF for 2 min and then 20% piperidine in DMF for 10 min at room temperature. Cleavage and cyclization. The protected branched peptide

En route to photoaffinity labeling of the bacterial lectin FimH

• Thisbe K. Lindhorst,
• Michaela Märten,
• Andreas Fuchs and
• Stefan D. Knight

Beilstein J. Org. Chem. 2010, 6, 810–822, doi:10.3762/bjoc.6.91

• remove the Fmoc protecting group. The solvent was removed in vacuo and the resulting crude product combined with HATU (11.3 mg, 29.7 μmol) and the diazirine 11 (7.2 mg, 31.0 μmol), and dry DMF (1.5 mL) added under a nitrogen atmosphere. DIPEA (0.03 mL, 87.0 μmol) was then added and the reaction mixture

• glycoamino acid derivative 10 (19.6 mg, 23.2 μmol) was dissolved in piperidine (20% in DMF, 1.5 mL) and stirred at RT for 60 min to remove the Fmoc protecting group. The solvent was removed in vacuo and the resulting crude product combined with HATU (14.0 mg, 36.8 μmol) and the diazirine 11 (7.2 mg, 30.9

Synthesis of glycosylated β³-homo-threonine conjugates for mucin-like glycopeptide antigen analogues

• Florian Karch and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2010, 6, No. 47, doi:10.3762/bjoc.6.47

• conditions using piperidine in N-methylpyrrolidone (NMP) to remove the temporary Fmoc protecting group followed by coupling of excess (10 equiv) Fmoc-amino acid activated by HBTU/HOBt [39] and diisopropylethylamine (DIPEA) in DMF. Unreacted amino acids were capped after each cycle with Ac2O in the presence

(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

• ., gougerotin 3 and aspiculamycin 4) (Figure 2). N-Acetylneuraminic acid is a readily available naturally occurring δ amino acid. By applying solid phase peptide methods on Rink resin with Fmoc protecting group chemistry [21][22], Gervay and co-workers have reported a series of (1→5) amide-linked sialooligomers

Synthesis of novel photochromic pyrans via palladium- mediated reactions

• Christoph Böttcher,
• Gehad Zeyat,
• Saleh A. Ahmed,
• Elisabeth Irran,
• Thorben Cordes,
• Cord Elsner,
• Wolfgang Zinth and
• Karola Rueck-Braun

Beilstein J. Org. Chem. 2009, 5, No. 25, doi:10.3762/bjoc.5.25

• the presence of an Fmoc protecting group for the direct synthesis of ω-amino acid 6. Also, a Sonogashira reaction was conducted towards the synthesis of naphthopyran precursor 4, which is suitable for attachment to tripodal linker systems for the immobilization on surfaces [26]. Results and Discussion

• , necessary here because of the sensitivity of the Fmoc protecting group. However, in a procedure published by Urata et al. [31] the use of molecular sieve instead of base was successful. The reaction outcome was dependent on the molecular sieves type, since the pore diameter must correspond to the ion size

A practical synthesis of the ¹³C/¹⁵N- labelled tripeptide N-formyl- Met-Leu-Phe, useful as a reference in solid- state NMR spectroscopy

• Sven T. Breitung,
• Jakob J. Lopez,
• Gerd Dürner,
• Clemens Glaubitz,
• Michael W. Göbel and
• Marcel Suhartono

Beilstein J. Org. Chem. 2008, 4, No. 35, doi:10.3762/bjoc.4.35

• [16][17]. (See Supporting Information File 1.) In case of a successful peptide extension, the Fmoc-protecting group was removed with piperidine (25% in DMF). Afterwards, the last coupling step was started by adding a solution of 13C/15N-labelled Fmoc-Met-OH (250 mg, 0.66 mmol), HOBt*H2O (145 mg, 0.945

• mmol) and DIC (145 µL, 0.945 mmol) in NMP (2.5 mL). In case of quantitative coupling (Kaiser test), the Fmoc-protecting group was removed and the resin was washed with DMF (5 ×) and CH2Cl2 (5 ×). The beads were dried in the syringe under reduced pressure. Formylation of the N-terminus: For the