Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• -monomethylation of the primary amino group of compound 25 by alkylation with methyl iodide or by Eschweiler–Clarke reductive amination with formaldehyde and formic acid were unsuccessful, because the dimethylated byproduct was also formed, even when one equivalent alkylating agent was used. Finally, our efforts

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• ) was used. MeCN/MeOH/H2O mixture with 50 mM formic acid and 25 mM diethylamine was used as eluent. A flow rate of 0.5 mL/min was applied and the detection of the respective compounds occurred at 280 nm. Data analysis was carried out with the EZChrom ELITE software (version 3.3.2 SP2, Agilent). Ni(II

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• -UV system [column 2.1 × 50 mm, 1.7 μm, C18 Acquity 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, RF = 0.6 mL/min, UV–vis detection 200–600 nm]. NMR spectra were

• ), solvent A: H2O + 0.1% formic acid; solvent B: acetonitrile (ACN) + 0.1% formic acid, gradient: 5% B for 0.5 min, increasing to 100% B in 20 min, maintaining isocratic conditions at 100% B for 10 min, flow = 0.6 mL/min, UV–vis detection 190–600 nm]. Preparative HPLC was achieved at room temperature on an

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• gradient elution was applied using a mobile phase consisting of solvent A: H2O + 0.1% formic acid (v/v) and solvent B: acetonitrile (MeCN) + 0.1% formic acid (v/v). The gradient started at 5% B, gradually increasing to 100% B over 20 min, followed by a 10 min hold at 100% B, with UV–vis detection in the

• acetone/MeOH (9:1, 7:3, 1:1, 0:1) along with one last fraction of MeOH 100% using 0.1% formic acid. Nine fractions of 1 L each were eluted that were collected and evaporated separately under reduced pressure to dryness. For fractions 3, 4, 6 and 8 were further purified using a PLC 2250 preparative HPLC

• phase consisted of deionized water (H2O) + 0.1% formic acid as solvent A and MeCN + 0.1% formic acid as solvent B. The flow rate was set at 30 mL/min for fractions 3, 4, and 8, and 20 mL/min for fraction 6. The collected fraction volume for each run was 15 mL. In the purification of fraction 3 (1,315 mg

Facile one-pot reduction of β-nitrostyrenes to phenethylamines using sodium borohydride and copper(II) chloride

• Laura D’Andrea and
• Simon Jademyr

Beilstein J. Org. Chem. 2025, 21, 39–46, doi:10.3762/bjoc.21.4

• mm, 1.7 µm) operated at 40 °C, using a linear gradient of the binary solvent system of buffer A (Milli-Q H2O/MeCN/formic acid, 95:5:0.1 v/v) to buffer B (MeCN/formic acid, 100:0.1 v/v) from 0 to 100% B in 3.5 min, then 1 min at 100% B, flow rate: 0.8 mL/min. Data acquisition was controlled by

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• ) in tetrachloromethane (CTC) to 588 nm (orange) in formic acid. Therefore, it was found that compound 1c was characterized by a large Stokes shift upon increasing the solvent polarity, which reached 150 nm (5824 cm−1) in formic acid. This was associated with the bathochromic shift of the emission band

• dimethylamino group, were studied (Table 1 and Figure 3). It was found that in most solvents, compound 1i was characterized by a single pronounced absorption maximum in the range of 503–525 nm that red-shifted upon increasing the solvent polarity. In formic acid, due to the protonation of the dimethylamino

• two observed absorption maxima: the first almost coincided with the corresponding maximum of the solution in formic acid, and the second one was in the same region as with other aprotic solvents. The emission maxima of stilbazole 1i were within a very wide range of 264 nm and covered almost the entire

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• Suzuki couplings and the reduction of the thiazole moiety to 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a crucial intermediate, using BH3⋅NH3 and tris(pentafluorophenyl)borane as a Lewis acid, followed by treatment with formic acid. Gillie et al. reported the synthesis of a laterally fused N-heterocyclic

Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers

• Andreas Wiest and
• Pavel Kielkowski

Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199

• conjugates may be carried out using desthiobiotin (DTB) as affinity tag instead of biotin [103][104]. The DTB-tag allows to elute probe–peptide–DTB conjugates from streptavidin beads using a mixture of water, organic solvent – typically acetonitrile (ACN) – and an acid such as formic acid. The desthiobiotin

Deuterated reagents in multicomponent reactions to afford deuterium-labeled products

• Kevin Schofield,
• Shayna Maddern,
• Yueteng Zhang,
• Grace E. Mastin,
• Rachel Knight,
• Wei Wang,
• James Galligan and
• Christopher Hulme

Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195

• ]. Results and Discussion We hypothesized that [D1]-aldehydes could be converted to [D2]-benzylic isocyanides using [D2]-formic acid via Leuckart–Wallach reaction followed by dehydration. Surprisingly, the Leuckart–Wallach reaction gave [D3]-formamides which are scarce in the primary literature. The common

• Leuckart–Wallach methodology developed herein, deuterated aldehydes can be converted into [D2]-isocyanides. The optimized conditions for this reaction are summarized below (Table 1). It is important to note that 1 equivalent of formamide and excess [D2]-formic acid (Table 1, entry 2) leads to increased

• increased the overall yield of the reaction (Table 1, entry 5). In summary, minimal formamide (1–2 equiv), excess [D2]-formic acid, and heating to 170 °C in a microwave reactor for 5 minutes is expected to give excellent yields in good deuteration %. A tentative mechanism to [D3]-formamides is shown in

Mining raw plant transcriptomic data for new cyclopeptide alkaloids

• Draco Kriger,
• Michael A. Pasquale,
• Brigitte G. Ampolini and
• Jonathan R. Chekan

Beilstein J. Org. Chem. 2024, 20, 1548–1559, doi:10.3762/bjoc.20.138

• . Afterward, the extract was resuspended in 0.1% formic acid in water. A Combiflash EZ prep system was used to purify the burpitides from C. americanus. Water with 0.1% formic acid (A) and methanol (B) were used as solvents for a reversed phase column (C18 21 × 250 mm Kinetix 5 µm C18 100 Å (00G-4601-P0-AX5

• min, 5% B; 13 min, 5% B where solvent A was water with 0.1% of formic acid and solvent B was acetonitrile with 0.1% of formic acid. A top 5 HCD method at 25 NCE (200–2000 m/z) was used on each plant tissue extract. See Supporting Information File 1, Table S2 for complete acquisition parameters. The

• individually and as a combined mixture (5 µL) onto UPLC-MS (Thermo Orbitrap Elite mass spectrometer coupled to a Dionex Ultimate 3000 UPLC), with a gradient of 15–50% B over 10 min on a Kinetex 1.7 µm C18 100 Å 50 × 2.1 mm LC column using solvents of A: 0.1% formic acid in water and B: 0.1% formic acid in

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• produce a carboxylic acid (R1CO2H) and a primary alcohol (R1CH2OH). When a mixture of formaldehyde (HCHO) and a non-enolizable aldehyde (R1CHO) is treated with a strong base, the latter is preferentially reduced to the alcohol (R1CH2OH) while formaldehyde is oxidized to formic acid (HCO2H). Herein excess

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• 2018, 2022 and 2023, developed three procedures for the synthesis of substituted indoles from functionalized nitro compounds by using, in the first two cases phenyl formate as CO source [39][40] and, in the third case formic acid [41]. All of three processes allow the use of inexpensive reactors, in

• 2022, some substrates led to a non-selective reaction (Scheme 20). On the other hand, in the approach in which formic acid was used, the catalyst system was Pd(acac)2/1,10-phen. Also, in this case the addition of Et3N favored the reaction, moreover, Ac2O was added as additive (Scheme 21). At the same

• (indolyl)methane compounds were isolated in moderate and excellent yields after 24 hours in DMSO, Et3N and formic acid as additives and, Pd(PPh3)2Cl2/P(o-tolyl)3 as catalyst system. The reaction conditions and some important BIMs synthesized are shown in Scheme 42. In the second paper they used

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• grade and contained 0.1% vol/vol formic acid. Protein expression and purification The vectors to express Vs NnlA and H73A Vs NnlA were previously reported [21]. Pd, Mr, Ms, Ps, and Pj nnla genes were synthesized as E. coli codon-optimized constructs and cloned into the NdeI and XhoI restriction sites of

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• a charged state of 3+ (Figure S2, Supporting Information File 1), C60–oligo-Glu (5b) was confirmed by HRMS–MALDI (Figure S11, Supporting Information File 1) due to insolubility in the acidic eluent generally used for HRESIMS (a mixture of MeOH and water containing 0.1% formic acid). C60–oligo-Arg

New variochelins from soil-isolated Variovorax sp. H002

• Jabal Rahmat Haedar,
• Aya Yoshimura and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2024, 20, 692–700, doi:10.3762/bjoc.20.63

• filter, and then injected into an LC–MS system, Cosmosil 5C18-MS-II (2 mm ID × 100 mm, Nacalai Tesque) (oven 40 °C; flowrate 0.2 mL/min) using a gradient of MeCN/H2O (1:9 to 6:4) containing 0.1% formic acid for 45 minutes. The standards were processed in the same manner. Whole genome analysis of

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• % yield (Table 1, entry 14). The borane group could be cleaved off easily by the subsequent treatment of 17c with formic acid in acetonitrile, affording 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine 7c as the only reaction product. By applying this optimized two-step procedure to [1,3]thiazolo[4,5-b]pyridines 5

• diphenyl analogue 17f was isolated as a side product upon arylation with B(C6F5)3, debromination was only observed in traces. Both aminoboranes 17d and 17e were then cleaved separately in clean conversions using formic acid to afford the desired substituted 6-bromo-5-(2-tolyl)-2,3-dihydrothiazolo[4,5-b

• entirely unexplored prior to our investigations. Likewise, we identified an optimized BH3⋅NH3-mediated reduction involving tris(pentafluorophenyl)borane as a strong Lewis acid and subsequent treatment with formic acid as the most suitable conditions to prepare the desired 2,3-dihydro[1,3]thiazolo[4,5-b

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• flowthrough fraction was adjusted to 3 with formic acid (FA) and chromatographed again on HP20 column. Now, 1 was retained in the resin and eluted by 50% MeOH with 0.05% FA. Then 1 was purified by silica gel and ODS column chromatography, and ethyl acetate extraction under acidic conditions. As the result of

• analyzed by LC–MS. The flow-through and 0% fractions were mixed and adjusted to pH 3 by adding formic acid (FA). Then, the mixture was purified by eluting with MeOH/H2O (0%, 50%, and 100%) with 0.05% of FA through a HP20 column (55 i.d. × 500 mm). The 50% fraction was concentrated in vacuo to remove MeOH

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• eluting with H2O + 0.1% formic acid and MeCN + 0.1% formic acid using a gradient from 90:10 to 10:90 of H2O/MeCN over 15 min, maintaining in 10:90 H2O/MeCN for 3 min, from 10:90 to 90:10 in 1 min, and maintaining at 90:10 for 1 min, using a flow rate of 1.0 mL/min. The PDA detector scanned between λ = 190

• /H2O (50:50; v/v) containing 0.1% formic acid. The parameters such as declustering and entrance potentials remained constant for MS and MS/MS were set up at 150 V and 10 V, respectively. Collision energy for MS and MS2 scan surveys was 10 V and 45 V, respectively, with a collision energy spread of 12 V

• consisted of H2O + 0.05% formic acid (eluent A) and MeCN + 0.05% formic acid (eluent B), which was eluted of 20–100% of B with flow rate of 18 mL min−1, yielding 20 fractions. Fractions Fr13 and Fr15 were subjected to a purification by semipreparative HPLC-UV using a Premier RP18 column (250 mm × 10 mm i.d

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• formation of DBDAP, prompted us to test alternative CO surrogates. When the reaction was performed using Co2(CO)8 (0.3 equiv) in the presence of DBU, the intermediate 3a was isolated in 35% yield, but again no DBDAP 4 was obtained (entry 8, Table 1). Formic acid, an effective CO surrogate [20][22], was also

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• 2.6C18 Packed column (2.1 mm ID × 100 mm, Nacalai Tesque) coupled with a model LCMS-8040 liquid chromatography–mass spectrometer (LC–MS) (Shimazu Corp.). The compounds were eluted with a linear gradient of water/acetonitrile containing 0.1% formic acid. Isolation and structural determination of compound

• -II (10 mm ID × 250 mm, Nacalai Tesque), and the metabolites were eluted with a linear gradient of water/acetonitrile containing 0.1% formic acid. Fractions containing compound 6 were concentrated by evaporation. Compound 6 was then desorbed in DMSO-d6, and the structure was determined by the JNM-A600

• 30 °C for 1 h. After centrifugation, the supernatant was analyzed using LC–MS equipped with a BioResolve RP mAb polyphenyl column (2.1 mm ID × 100 mm, Waters, Milford, MA, USA). The compounds were eluted using a linear gradient of water/acetonitrile containing 0.1% formic acid. In vitro analysis of

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• products) [26]. HPLC: Phenomenex Lux Cellulose-3 column (3 mm, 250 × 4.6 mm), eluent CH3CN/H2O (0.1% formic acid) 40:60, isocratic mode; 0.6 mL min−1; UV detector 222 nm, 30 °C. The retention time for the (S)-enantiomer was 12.3 min, for the (R)-enantiomer 14.7 min. General procedure for recycling of the

• 164.4, 163.9, 135.1, 133.7, 130.7, 129.5, 106.9, 76.1, 49.0, 41.4, 36.8, 36.7, 29.8, 21.8 ppm; HRESI(+)-MS (m/z): [M + Na+] calcd for C17H18ClNO6Na, 390.0720; found, 390.0682; HPLC: Phenomenex Lux Cellulose-3 column (3 mm, 250 × 4.6 mm), eluent CH3CN/H2O (0.2% formic acid) 40:60, isocratic mode; 1 mL

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• transition-metal-based complexes, the outcomes are generally two-electron reduction products, such as carbon monoxide (CO), formic acid (HCO2H), or formate (HCO2−). To mitigate the strong energetic requirements of the reaction shown in Equation 1, the reduction of CO2 occurs in the presence of protons, so

• that the energy barriers of the reactions shown in Equation 2 and Equation 3 are lowered. In fact, the formation of the radical anion CO2−· takes place at −1.9 V versus normal hydrogen electrode (NHE), while the proton-assisted reductions of CO2 to CO and formic acid happen at −0.53 V and −0.61 V

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• -VAP Expert, Germany). HRESIMS spectra were recorded with an Agilent 1200 Infinity Series HPLC-UV system (Agilent Technologies; column 2.1 × 50 mm, 1.7 µm, C18 Acquity 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

• : deionized water (H2O) + 0.1% formic acid (FA) and solvent B: acetonitrile (ACN) + 0.1% formic acid. The binary gradient was: linear of 5% B for 5 min, automatic stepwise gradient from 5 to 100% B for 5–105 min, followed by 100% B for 10 min wash, and finally by 80% ACN + 20% H2O for 10 min re-equilibration

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• , followed by cyclization with glyoxal in formic acid. We then wished to slightly perturb the electron density via introduction of fluorine (either at R1 or R3), but it was at this time that an unexpected result was observed. Following the same conditions which produced B1, NMR evaluation of our next product