Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• ongoing challenge. Cryptophycins are a class of cyclic depsipeptides renowned for their high cytotoxicity in the picomolar range often combined with efficacy against multidrug-resistant tumour cell lines. However, cryptophycins failed as stand-alone drugs in cancer treatment, and their naturally occurring

• isolation from cyanobacteria [2], their extraordinarily high cytotoxicity was apparent and attracted attention, not least because of their still high efficacy against multidrug-resistant (MDR) cells [3]. Cryptophycin-52, a synthetic development candidate by Eli Lilly based on the initially discovered

• relationship (SAR) studies between derivatisations of all four units (A to D) (Figure 1A) of cryptophycin-52 analogues with functional groups [8]. While many modifications of cryptophycin decrease the cytotoxicity drastically, some viable attachment points for conjugation were found, mainly including the para

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• prepare concentrations sufficient for studying cellular cytotoxicity. In this regard, 1,3-tropolone 7a, which has an acceptable level of solubility in water, was used for biological testing. The in vitro cytotoxic activity was investigated with A431 skin cancer and H1299 lung cancer cell lines. A standard

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

• cell viability. Conclusion Among the isolated compounds, and based on the results of bioassays, farinosones D (1) and A (2) were selected as potential candidates for biofilm assays due to their minimal to weak cytotoxicity. Microbiological assays aimed at identifying potential targets within the S

• microorganisms (A. baumannii, B. subtilis, and M. smegmatis), ciprofloxacin, oxytetracycline, and kanamycin were used as positive controls. Cytotoxicity assays The cytotoxic potential of the isolated compounds was determined using the MTT assay over a concentration range of 1 to 37 µg/mL against two mammalian

• with farinosones D (1) and A (2), microporenic acid A (MAA) as a positive control and methanol as a solvent control and taken as 100%. 1H and 13C NMR data of farinosone D (1). Cytotoxicity (IC50) and antimicrobial activity (MIC) of 1–6. Inhibition of biofilm formation of S. aureus by 1 and 2

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• , red-light photocatalysis enables innovative applications in phototherapy and controlled drug release, exploiting its tissue penetration and low cytotoxicity. Together, these developments underscore the versatility and impact of red-light photocatalysis, positioning it as a cornerstone of green organic

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• results in one case, providing high cytotoxicity toward the MCF-7 cancer cell line. The stable axial chirality of the products 71 and 73 was confirmed by calculations of the rotational barriers ranging from 30.2 to 46.3 kcal/mol. Kinetic resolution by amino group protection of biaryls (R,S)-74a–r with

• and stereoselectivities (85%, 90% ee, >95:5 E/Z). A biological activity investigation led to promising results in the case of one substrate displaying cytotoxicity towards several cancer cell lines. Organocatalytic enantioselective construction of axially chiral styrenes 175 and 177 was done utilizing

• enantiopurity at 130 °C for 48 h in toluene. Investigating the biological activity for a number of compounds, good cytotoxicity was reported for five kinds of cancer cells. The mechanistic study suggests that the indole ring of the substrate is having a crucial role in the reaction mechanism because replacing

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• cytotoxicity against L1210 murine leukemia cells and KB epidermoid carcinoma cells. Keywords: ceratinadin; cytotoxicity; marine sponge; psammaplysin; Pseudoceratina sp.; Introduction Marine sponges are widely recognized as a rich source of unique bioactive natural products. For instance, marine sponges

• data of the 8,10-dibromo-9-methoxy-1,6-dioxa-2-azaspiro[4.6]undeca-2,7,9-trien-4-ol moiety of 1 and the ECD spectrum pattern of 1 matched those of compound 2 (Figure 3). Consequently, the absolute configuration of 1 was assigned as 6R and 7R, identical to that of 2. The in vitro cytotoxicity of

• C24H2679Br281Br2N4O6Na, 808.84426; found, 808.84502. Cytotoxicity assay L1210 murine leukemia cells were cultured in RPMI-1640 supplemented with 10% FBS, and KB epidermoid carcinoma cells were cultured in DMEM supplemented with 10% FBS. All cells were incubated at 37 °C in a humidified atmosphere of 5% CO2 and 95% air

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

• be inactive. The activities of β-33b and 34 on the cell viability was independently studied by using crystal violet as a dye for viable cells following a 48 h incubation of A375 melanoma cells and A431 squamous carcinoma cells. Interestingly, a concentration-dependent cytotoxicity was again observed

• ). While isoindigo-N-glycosides did not show cytotoxicity, two azaisoindigo-N-glycosides exhibited significant antiproliferative activities with cell proliferation inhibition of all the cell lines tested in a 75–80% range. The best activity was observed, in fact, for compound β-58d. Isoindigo-N,N

Synthesis and cytotoxicity studies of novel N-arylbenzo[h]quinazolin-2-amines

• Battini Veeraiah,
• Kishore Ramineni,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Hélène Solhi,
• Rémy Le Guevel,
• Chada Raji Reddy,
• Frédéric Justaud and
• René Grée

Beilstein J. Org. Chem. 2024, 20, 2592–2598, doi:10.3762/bjoc.20.218

• this paper, we report a short and efficient synthesis of novel N-arylbenzo[h]quinazoline-2-amines. We have prepared a focused library of nineteen representative examples which have been submitted to cytotoxicity assays against a representative panel of eight cancer cell lines and several molecules gave

• attractive results in this area. Keywords: Buchwald–Hartwig coupling; cytotoxicity; heterocycles; Pd catalysis; quinazolines; Introduction Nitrogen-containing heterocyclic molecules are ubiquitous in living systems. Among them, quinazolines, and especially the 4-aminoquinazolines (type A molecules, Figure

• compounds with two substituents or with three fluorine atoms. All these compounds have been obtained in fair yields (51–70%) and they have spectral and analytical data in agreement with the indicated structures, as given in the experimental section and Supporting Information File 1. Cytotoxicity studies

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• turned out that induced cytotoxicity [75] is mediated by activation of the mitochondrial pathway of apoptosis in human colon carcinoma cells [76][77] and that cytotoxicity on HCT116 cells is increased, when AOH is combined with 9-O-methylalternariol (2, AME) [78]. AOH further showed to have a detrimental

• tested for cytotoxicity, but turned out to be inactive. Altertenuol (31) has already been mentioned in one of the first reports on metabolites isolated from Alternaria tenuis (synonymous to A. alternata) [42][54]. Its structure was determined by chemical methods and has later been confirmed after total

• weight) [11][74], and showed toxicity against brine shrimp larvae (Artemia salina) with an LD50 value of 375 µg/mL [256][257]. It exhibited cytotoxicity against HeLa cells (ID25: 28 µg/mL) [74], the HCT116 cancer cell line (IC50: 3.13 μM) [232], and against MG-63 cells (IC50: 17.8 µg/mL) [123]. An

Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384

• Marwa Elsbaey,
• Naoya Oku,
• Mohamed S. A. Abdel-Mottaleb and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174

• by formyl and carboxyl functionalities. Compounds 1, 4, and 5 showed cytotoxicity against Kasumi-1 human acute myeloblastic leukemia cells with IC50 values of 103, 105, and 105 μM, respectively, which are less active than the anticancer agent cisplatin, with an IC50 value of 70 μM. Keywords

• cytotoxicity against Kasumi-1 human acute myeloblastic leukemia cells with IC50 values of 103, 105, and 105 while 2 and 3 were less active with IC50 values of 200 and 333 μM, respectively. Under the same experimental conditions, cisplatin, a positive control, inhibited the cell growth with an IC50 value of 70

• substitution patterns are different (Figure 1). Natural alkylpyrroles were shown to have cytotoxicity [27], antidiabetic activity [28], anti-lipid peroxidation [12], in vivo antihypoxic activity [12], and antibacterial activity [15]. Though not impressive in cytotoxicity and tyrosinase-inhibitory evaluations

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• with IC50 values ranging from 0.7 to 43 µM, some of them exhibiting significantly more potent activity than the reference compound 5-fluorouracil (5-FU). More recently, similar compounds were evaluated for their cytotoxicity using a brine shrimp bioassay, with LC50 values ranging from 6.19 to 27.2 µg

• /mL. Since the cytotoxicity of the parent 16-arylidene steroids was LC50 > 100 µg/mL, it was concluded that the presence of the pyrrolidine moiety was essential for the activity [28]. Additional derivatives have been reported on different steroidal positions [29] or with variations in the methodology

• . Chromatographic purification was not required post-reaction. Some spiro products exhibited high binding affinity towards DNA, while others showed good cytotoxicity against different cancer cells (A545, MCF-7, HeLa, HL-60, SW480, HepG2, HT-29, and A549) with IC50 values within the micromolar range (2.18–18.54 µM

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• proteusin family of RiPPs. They are produced by the tunicate symbiont Candidatus Entotheonella factor and exhibit membrane activity against Gram-positive bacteria and are highly cytotoxic. Cytotoxicity was tested with murine leukaemia cells; polytheonamide A, B, and C showed IC50 values between 68 and 78 pg

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• Gram-positive bacteria Kocuria rhizophila and S. aureus, Gram-negative bacterium Tenacibaculum maritimum, and a panel of fungi. These molecules also demonstrated moderate cytotoxicity against P388 murine leukemia cells. The bisindole alkaloid violacein (24, Figure 8) was isolated and characterized from

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• systematically by visible light irradiation. On a macroscopic length scale, the soft DAn scaffolds were able to perform macroscopic structure disassembly upon visible-light irradiation. The biocompatibility of the macroscopic soft DAn scaffolds was investigated, revealing limited cytotoxicity. The current work

• scaffolds were further incubated with hBM-MSCs cells, promoting the attachment of cells onto the surface. The limited cytotoxicity and good stability of DAn macroscopic soft scaffolds points at an application as cell–material interface and even offers opportunities for the fabrication of biomedical

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• minor products and mostly starting material, hence we decided these products were not worth further purification. The minor isomers of the halogenated derivatives were presumably detected but in too low yields to purify. Since 6/6/6-tricyclic diterpenes are known to show cytotoxicity [26], we tested our

• seven analogs for cytotoxicity against human colon carcinoma HCT-116 cells. Unfortunately, none of the compounds up to 10 μM showed any activity when tested in MTT-based cell viability assays. Conclusion Eunicellane diterpenoids have been known for over 50 years, but it was not until recently that their

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• ) being active at 5 μg/mL, using a 75% cutoff inhibition at each concentration. On the other hand, MCF-7 and SK-MEL-28 cells were the most resistant ones, with no compound being active at the lower concentration (Figure 5). This evidence of selective cytotoxicity for a specific histological tumor subtype

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• ]. DIM has also been found to initiate the expression of tumor suppressing proteins (ATM, p21, p27kip), which control cell growth and protect cells against ionizing radiation, which can cause DNA mutations, decreasing the overall risk of breast cancer [1][5][6]. The cytotoxicity of DIM and BIMs in

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• cells within the concentration range. This indicates the low cytotoxicity of these compounds. Meanwhile, compounds 3m,l are characterized by a borderline inhibition of cell culture viability. Attention is drawn to the increased toxic effect of 3m on cells of tumor origin, in comparison with normal human

• (method A)a; 1 (0.5 mmol), 2 (0.5 mmol), NaOH (0.5 mmol), EtOH (2 mL), 0 °C → rt, 30 min (method B)b. Proposed mechanism for the formation of triazoles 3. Optimization of the reaction of amidine 1a with 6-azidopyrimidine-2,4-dione 2a.a Cytotoxicity index (IC50 ± SE) in µM of the studied compounds on human

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• monoamine oxidase [14], cytotoxicity against cancer cell lines [15], activity against nuclear factor of activated T cells [16], and anti-inflammatory activity [17]. Alkaloids with similar structure and anti-inflammatory activity have been isolated from another member of the Rutaceae family – Zanthoxylum

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• cell membrane integrity [21]. In the context of cancer therapy development, metal complexes of N-acylhydrazones stand out. For example, Firmino et al. demonstrated that gallium(III) complexes of isoniazid-derived hydrazones exhibit strong cytotoxicity against HL-60 and HCT-116 cancer cell lines [22

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• revealed that compound 7 was cytotoxic to RAW 264.7 cells at concentrations above 25 μM (Figure 6d). Furthermore, 7 suppressed the LPS-induced increases in IL-1β and IL-6 transcriptional levels in a concentration-dependent manner from 1 or 2.5 μM (Figure 6e). Thus, while cytotoxicity was likely involved in

• the suppression of mRNA levels at high concentrations (>25 μM) of compound 7, anti-inflammatory effects occurred at lower concentrations without cytotoxicity. The production of IL-1β and IL-6 was also evaluated by an enzyme-linked immunosorbent assay (ELISA) using culture supernatants. The LPS

• the LPS-only group)]; d) concentration-dependent cytotoxicity of 7 in RAW 264.7 cells (cell viability was detected by an MTT-based colorimetric assay); e) mRNA levels of IL-1β and IL-6 in RAW 264.7 cells preincubated with different concentrations of compound 7 for 24 h, followed by treatment with LPS

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

• tumor cytotoxicity effects for a number of the berberine derivatives. Keywords: benzylisoquinoline; berberine; chelerythrine; drug discovery; plant-derived antimicrobials; Introduction The isolation, or creation of novel antimicrobial agents is currently at the forefront of modern healthcare due to

• unique compounds at a set concentration against T84 human colon cancer cells has provided useful preliminary comparative cytotoxicity data, which can be directly compared to our previous publication showing the effects of crude A. mexicana extracts against this same cell line [9]. However, further

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• has similar cell toxicity than edelfosine-C18 on HL-60 leukemic cells [129][130]. The authors also reported that the sulfone 26.5 (Figure 26B) had similar cytotoxicity than edelfosine-C18. In 1987, the group of E. J. Modest reported that the thioether 26.4 featured comparable cytotoxicity than C18

• . The replacement of the oxygen atom located in sn-1 position by a methylamino group corresponds to a compound known as BN52211 (30.6, Figure 30). This compound was used in many studies for its antitumor cytotoxicity [136] or its immunologic properties [137]. To the best of our knowledge, the synthesis