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

• ammonolysis in methanol affords compound 1c. The silylation of 1c with TBDPSCl was carried out, and then coupling reaction with tert-Boc-Met-Leu-Phe-OH in the presence of DCC and HOBt provided compound 98. The tert-Boc protecting group was further removed in formic acid, and the resulting nucleoside peptide

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• pyrrole derivatives: i) Knorr reaction: the condensation of α-aminoketones or α-amino esters in the presence of zinc powder and sodium acetate; ii) Paal–Knorr reaction: the condensation of 1,4-dicarbonyl compounds and amines, catalyzed by formic acid in anhydrous alcohol; iii) Hantzsch reaction: the

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

• materials. For example, Zhang et al. showed that refluxing anilide 177 in presence of a catalytic amount of Hg(OAc)2 and 90% formic acid gave the tricyclic heterocyclic scaffold 178 [113]. It involved a two-step process with the rearrangement of the primary cyclization products (Scheme 53). In 2013, Lin et

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• acid, or its metal salt in acetonitrile or as a 50:1 mixture of acetonitrile/formic acid at −40 to 0 °C. The yields were good to excellent [86] (Figure 7). The trimer 24-3 and polymer homologues 24-4 were also prepared. The N,N’-difluorobipyridinium salts are stable and generally furnished non

Analogs of the carotane antibiotic fulvoferruginin from submerged cultures of a Thai Marasmius sp.

• Birthe Sandargo,
• Leon Kaysan,
• Rémy B. Teponno,
• Christian Richter,
• Benjarong Thongbai,
• Frank Surup and
• Marc Stadler

Beilstein J. Org. Chem. 2021, 17, 1385–1391, doi:10.3762/bjoc.17.97

• , Bruker, Bremen, Germany) [column 2.1 × 50 mm, 1.7 µm, C18 Acquity UPLC BEH (Waters, Eschborn, Germany)], with deionized water + 0.1% formic acid (solvent A) as well as acetonitrile + 0.1% formic acid (solvent B) and a gradient of 5% B for 0.5 min increasing to 100% B in 19.5 min, maintaining 100% B for 5

• (Phenomenex, Inc., Aschaffenburg, Germany) and subsequently pre-fractionated utilizing RP-HPLC with a Gilson PLC 2250 purification system (Middleton, WI, USA) and a VP Nucleodur 100-5 C18 ec 250 × 40 mm, 7 µm column (Macherey-Nagel, Düren, Germany). Acetonitrile + 0.1% formic acid and deionized water + 0.1

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• was subjected without purification to LC–MS analysis (0.7 mL/min; 25% aqueous CH3CN with 0.1% formic acid for 30 min). The authentic samples of ᴅ-glucopyranose and ʟ-glucopyranose were derivatized and analyzed by the same method as described above. The hydrolysate derivative of compound 1 was detected

Semiautomated glycoproteomics data analysis workflow for maximized glycopeptide identification and reliable quantification

• Steffen Lippold,
• Arnoud H. de Ru,
• Jan Nouta,
• Peter A. van Veelen,
• Magnus Palmblad,
• Manfred Wuhrer and
• Noortje de Haan

Beilstein J. Org. Chem. 2020, 16, 3038–3051, doi:10.3762/bjoc.16.253

• File 2) but may occur at the peptide portion as well [24][25][26]. Formylation is likely introduced by the exposure of the tryptic peptides to formic acid during the acid precipitation of sodium deoxycholate in the final step of the sample preparation and during subsequent storage [24]. Within the

• agitation, the beads were washed three times with PBS and three times with water. The immunoglobulins were released by acid elution (100 mM formic acid) and collected into a 96-well PCR plate (Greiner Bio-One, Kremsmünster, Austria). Finally, the eluates were dried for 2.5 h at 60 °C by centrifugation under

• to room temperature. Tryptic digestion was started by the addition of 50 µL digestion buffer containing 50 mM ammonium bicarbonate pH 8.5 and 200 ng sequencing-grade trypsin. Upon mixing for 5 min, the sample was incubated at 37 °C overnight. Acid precipitation using 1.2 µL formic acid was performed

Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations

• Ian Walsh,
• Matthew S. F. Choo,
• Sim Lyn Chiin,
• Amelia Mak,
• Shi Jie Tay,
• Pauline M. Rudd,
• Yang Yuansheng,
• Andre Choo,
• Ho Ying Swan and
• Terry Nguyen-Khuong

Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176

• of the RFMS-labelled glycans was performed using a 96-well GlycoWorks HILIC μElution Plate (Waters Corp). The plate was initially equilibrated with sequential washes with dH2O and 85% ACN. The samples were loaded onto the wells and washed with 90% ACN/1% formic acid (FA). The glycans were eluted with

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• -butyl esters with formic acid gave the carboxylic acid 9, 7, or 5. Additionally, the treatment of the thailanstatin A tert-butyl ester with lithium chloride generated the thailanstatin B tert-butyl ester. Ghosh used a similar cross-metathesis/Suzuki–Miyaura coupling sequence for the preparation of

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• 1.5 h in an ethanol/water (50:50) mixture at 210 °C, and ii) CIMV (Compagnie Industrielle de la Matière Végétale) technology, where wheat straw was treated during 3.5 h of acetic acid/formic acid/water (50:30:15 m/m/m) extraction at 105 °C and then in the presence of H2O2 and organic acids (peracetic

A dynamic combinatorial library for biomimetic recognition of dipeptides in water

• Florian Klepel and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2020, 16, 1588–1595, doi:10.3762/bjoc.16.131

• stirring overnight (100 rpm), the samples were acidified with a 5% solution of formic acid in water. The samples were diluted 1:10 with water and measured with HPLC–MS setup I. HPLC–MS measurements The HPLC setup was based on a Shimadzu system and consisted of a CBM-20A controller, a SIL-HTA auto sampler

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• (Scheme 4). According to the literature, the N-debenzylation by a Pd-catalyzed hydrogenolysis in methanol with formic acid as the hydrogen source [37][38] should allow the access to N-deprotected isoxazolidines. Unfortunately, all attempts to remove the benzyl group directly from the model isoxazolidine

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• an ESI–TOF mass spectrometer (Agilent 6220 Time-of-Flight), gas temperature – 350 °C, drying gas (N2) – 8.0 L/min, mobile phase(s): methanol with 0.1% formic acid, flow rate: 0.2 mL/min, sample preparation: The sample was dissolved in 1 drop of chloroform and diluted with 1 mL methanol. Additional

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• dispersed in triethylorthoformate and some drops of formic acid were added. The mixture was heated at reflux for 20 h to receive the new functionalized nanoparticles 103. The nanoparticles 103 were dispersed in 1,6-diisopropylaniline (104) by ultrasonication. The mixture was heated at 120 °C for about 20 h

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• treated with triflic anhydride to afford the corresponding triflate 55. Microwave-assisted reduction of compound 55 with pyridinium chloride afforded the α-chloropyridine derivative 56, which was further catalytically dehalogenated with palladium on carbon and formic acid to generate the pyridine scaffold

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• mixture containing 0.1% (v/v) formic acid. Solutions were directly introduced into the ion source using a syringe pump. Under the applied conditions, the compounds form protonated molecules, [M + H]+ in positive ionization mode (ESI). Detailed experimental procedures, characterization data are reported in

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• , solvent A: H2O + 0.1% formic acid, solvent B: acetonitrile + 0.1% formic acid, elution gradient: 5% solvent B for 0.5 min, increasing solvent B to 100% within 19.5 min, 100% solvent B for 5 min, flow rate: 0.6 mL/min, UV–vis detection at λ = 200–600 nm) and ESI–TOF–MS analysis (maXis™ system, Bruker, scan

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• 200–800 nm, gradient: 0–10 min 5–95% MeCN with 0.1% formic acid, 10–15 min 95% MeCN with 0.1% formic acid) eluted 1 (tR 5.10 min), 2 (tR 4.79 min), 3 (tR 5.28 min), 4 (tR 5.96 min), 5 (tR 7.64 min), 6 (tR 6.00 min), 7 (tR 6.45 min), 8 (tR 4.85 min), 9 (tR 5.69 min), 10 (tR 6.37 min), 11 (tR 6.48 min

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

• Annika Stein,
• Dave Compera,
• Bianka Karge,
• Mark Brönstrup and
• Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

• , Waters 2424 ELS detector, and a Waters SQ Detector 2 for mass spectrometry in ESI+ and ESI– modes between m/z 150 and 1000. In analytical mode, a Phenomenex Kinetex column (2.6 µm, C18, 100 Å, 4.6 × 100 mm) was used with a gradient of [solvent A: H2O + 0.05% formic acid; solvent B: acetonitrile + 0.045

• % formic acid; gradient: 10% to 90% B over 10 min, 1 mL/min]. Samples were dissolved to a concentration of 10 mg/mL in MeOH and 20 µL injected. In preparative mode, a Phenomenex Kinetex Axia column (5 µm, C18, 100 Å, 21.2 × 250 mm) equipped with a Phenomenex Security Guard precolumn (Luna, C5, 300 Å) was

• separated by preparative LC–MS. The sample was dissolved in MeOH to a concentration of 15 mg/mL. 100 µL was injected per run. A separation gradient was used [solvent A: H2O + 0.05% formic acid; solvent B: acetonitrile + 0.045% formic acid; gradient: 10% to 90% B over 10 min, 20 mL/min]. The post-column flow

Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• , this was likely the result of the molecular ion losing the ruthenium and subsequently protonated in the mass spectrometer; this triazolium signal was also not seen in our model study. A final peak at 1030.4333 Da was assigned as [M – Cl + formic acid]+ (formic acid was present in the injection media

Stereo- and regioselective hydroboration of 1-exo-methylene pyranoses: discovery of aryltriazolylmethyl C-galactopyranosides as selective galectin-1 inhibitors

• Alexander Dahlqvist,
• Axel Furevi,
• Niklas Warlin,
• Hakon Leffler and
• Ulf J. Nilsson

Beilstein J. Org. Chem. 2019, 15, 1046–1060, doi:10.3762/bjoc.15.102

• through NOESY using pyridine-d5 as a shift reagent solvent. All final compounds were purified using preparative HPLC on an Agilent 1260 Infinity system with a SymmetryPrep C18 5 µM 19 × 100 mm column using a gradient (water with 0.1% formic acid and acetonitrile); 0–20 min 10–100% acetonitrile, 20–23 min

• using a gradient with water (0.1% formic acid) and acetonitrile using a flow rate of 0.50 mL/min and a column temperature 60 °C. Gradient parameters: 0–0.7 min: 40% acetonitrile, 0.7–10.0 min: 40–99% acetonitrile, 10.0–11.0 min 99% acetonitrile, 11.0–11.1 min 99–40% acetonitrile, 11.1–13 min 40

• % formic acid to 100% acetonitrile over 20 min, followed by 3 min of 100% acetonitrile) to give 1a (14 mg, 71%) as a white powder. [α]D20 24 (c 0.6, methanol); 1H NMR (400 MHz, CD3OD) δ 8.42 (s, 1H), 7.86–7.81 (m, 2H), 7.48–7.42 (m, 2H), 7.38–7.33 (m, 1H), 4.98–4.95 (m, 1H), 4.57 (dd, J = 14.4 Hz, 7.5 Hz

New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

• Frank Surup,
• Florian Hennicke,
• Nadine Sella,
• Maria Stroot,
• Steffen Bernecker,
• Sebastian Pfütze,
• Marc Stadler and
• Martin Rühl

Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98

• spectrometer (Bruker Daltonik), both combined with an Agilent 1200 series HPLC-UV system [column 2.1 × 50 mm, 1.7 μm, C18 Acuity UPLC BEH (Waters), solvent A: H2O + 0.1% formic acid; solvent B: ACN + 0.1% formic acid, gradient: 5% B for 0.5 min increasing to 100% B in 19.5 min, maintaining 100% B for 5 min

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• combinations were used to prepare PCL electrospinning solutions. In this work, a formic acid solution of CB[n] and a DMF solution of PCL were mixed as the electrospinning solution for PCL/CB[n] nanofibers. These solvents have been selected due to the fact that CB[n] is soluble in formic acid and DMF is a good

• solvent for PCL. Turbidity/precipitation was observed when the volume ratio of the formic acid solution of CB[n] in the mixed solution was higher than 20% due to the poor solubility of PCL in formic acid solution. In order to keep the CB[n] content in the mixed solution as large as possible, the ratio of

• formic acid/DMF was fixed to 20:80 (v/v). Initially, a series of bead-free PCL/CB[n] (n = 5, 6, 7, 8) nanofibers with different CB[n] loading percentages were fabricated by electrospinning (Scheme 1). The experimental results showed that the solubility of CB[5], CB[6] and CB[8] in formic acid was

Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• isoquinolines (Scheme 1) involved the following steps: alkylation of isoquinolines to afford isoquinolinium salts 1, its reduction with formic acid giving rise to tetrahydroisoquinolines 2 in a nearly quantitative yield, which upon alkylation gave quaternary salts 3, finally these salts underwent the Hofmann

• styrenes 5 with a cyclic tertiary amino group from 1,2,3,4-tetrahydroisoquinoline (Scheme 2). In this case, the initial isoquinoline was reduced in the presence of formic acid and then converted into the desired products 5 by a one-pot solvent-free reaction under the action of the corresponding dihalide in

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• property of the latter. As a substitute, cyano trimethylsilane was examined, however, this experiment did not afford the corresponding β-ketoenamide. Unexpectedly, using formic acid as the third component afforded only mixtures of compounds whose structures could not be elucidated. The role of formic acid