Search results
Search for "structure" in Full Text gives 2956 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B
Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197
- single crystals, and a corresponding X-ray diffraction analysis (inset in Scheme 3, selected H atoms have been omitted for clarity, and Table S3, Supporting Information File 1) unambiguously confirmed its precise structure with three continuous chiral centers. Conclusion In summary, the total synthesis
Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition
Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196
- synthesis and structural determination of malaymycin A (1) as well as the subsequent design of structural analogues for biological evaluation [16][17][18][19][20]. Preliminary structure–activity relationship (SAR) studies revealed that fungicidal activity is highly dependent on the nature and
Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity
Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195
- potential to load drug molecules in the bioactive nanoassembled structure. Keywords: anticancer agent; calixarene; nanostructure; self-assembly; Introduction Cancer remains one of the leading causes of morbidity and mortality worldwide. Despite significant advancements in chemotherapy, more effective and
- ). The proton signals of the NH₂ and CH₂S groups of the isothiouronium substituents were clearly observed at 9.04 ppm and 4.23 ppm, respectively. Additionally, the carbon signal of the CH₂S group appeared at 169.3 ppm. The NMR signals, consistent with a fully symmetric structure, evidenced the exhaustive
Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA
Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193
- efficient binding and further underscore the complexity of these systems due to conformational and energetic preferences. Taken together with previous studies, we postulate that future nucleobases should be designed to overcome the positional challenges related to entropy and geometry. (a) Structure of a
Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions
Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192
- ; membrane fluidity; membrane permeability; photoswitchable rotaxane; Introduction Lipid membranes play a vital role in biology by acting as protective barriers for cells and organelles while regulating the passage of substances. Additionally, their structure and dynamics influence the activity of membrane
- organelles within the same cell [2]. Therefore, there is a great need to develop molecular tools capable of modulating membrane structure in a controlled manner, either to facilitate cargo transport (such as drug delivery) [3][4], to irreversibly disrupt membranes and induce cell death (e.g., for targeting
- spatiotemporal precision [9]. Rotaxanes have emerged as promising tools for performing various functions in lipid membranes, owing to their multiple sites for derivatization, which allow fine-tuning of their structure and function in membranes. For instance, they have been used to transport ions across lipid
Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate
Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191
- isolation of compounds 2 and 3 in analytically pure form allowed their structure to be established thanks to elemental analysis and HRMS. It was found that compounds 2 and 3 are dimeric derivatives of the starting thiophene, linked by sulfur bridges located at the C-3 position instead of the nitro group
Synthesis of the tetracyclic skeleton of Aspidosperma alkaloids via PET-initiated cationic radical-derived interrupted [2 + 2]/retro-Mannich reaction
Beilstein J. Org. Chem. 2025, 21, 2470–2478, doi:10.3762/bjoc.21.189
- Education and Beijing National Laboratory for Molecular Science, and Peking-Tsinghua Centre for Life Sciences, Peking University, Beijing 100871, China Shenzhen Bay Laboratory, Shenzhen 518055, China Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical
- ). Further geometrical adjustment and conformational restriction of the transient structure enable the N9 nonbonding p orbital to align parallel to the σ(C19–C3)* orbital (Figure 2f, TS2 → F-10 → F-40 → IN3), which reinforces the hyperconjugative interaction. Facilitated by the bond stretching and bond-angle
- bending of the transient structure with a pseudo bicyclo[2.2.0]hexane unit, the favorable hyperconjugative interaction ultimately leads to cleavage of the C19–C3 bond (TS2 → IN3) and release of the ring strain. DFT analysis hereby explains that the orbital symmetry involved in this process does not
The intramolecular stabilizing effects of O-benzoyl substituents as a driving force of the acid-promoted pyranoside-into-furanoside rearrangement
Beilstein J. Org. Chem. 2025, 21, 2456–2464, doi:10.3762/bjoc.21.187
- energies of starting methyl β-galactopyranoside structure 1 were computed. The initial orientation of the methyl aglycon was chosen so that the torsional angle H1–C1–O1–C(Me) had the value of +40° for the β-structures and −40° for the α-isomers. The benzoate substituents at positions O-2 and O-3 were
- furanoside structure 2. Thus, when this angle had the starting values of 180° or −60°, all the calculations led to a conclusion that no transformation to a furanoside should occur (the resulting energies are given in Supporting Information File 1, Table S2). Only when optimizations started at the value of
Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds
Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185
- information. Keywords: biological activity; cyclopentane/enone; rearrangements; ring/cycle contractions; total synthesis; Introduction The functionalized cyclopentane/enone fragment is part of the structure of a large number of natural and synthetic biologically active compounds, including prostaglandins
- with two attached side chains – of seven (α-chain) and eight (β- or ω-chain) carbon atoms. Their main physiological role is to maintain the homeostatic harmony of the organism [1][2]. Among the terpenoids containing cyclopentane in their structure, we should mention jatrophane or latirane diterpenoids
- octahydrophenanthrene, is a natural follicular hormone essential for normal development of the female body [6]. An example of an alkaloid whose structure includes cyclopentane is lappaconitine, which is noteworthy because its hydrobromide is the active ingredient in the highly effective antiarrhythmic drug allapinine
The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions
Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184
- structure, results in elevated cis or trans diastereoselectivity [85][111]. Furthermore, the [3 + 2] cycloaddition reactions of nitrones with electron-poor dipolarophiles, such as N-phenylmaleimide, is controlled by the HOMO FMO of the nitrone. Consequently, it can be deduced that HOMOnitrone–LUMON
Synthetic study toward vibralactone
Beilstein J. Org. Chem. 2025, 21, 2376–2382, doi:10.3762/bjoc.21.182
- ][21]. Additionally, a series of vibralactone homodimers and oxime esters 10–12 were reported by the groups of Liu and Zhang, respectively [22][23]. Through modification of the primary hydroxy group, a structure-based optimization of vibralactone (6) was carried out by Liu and co-workers and yielded
- several potent pancreatic lipase inhibitors with nanomolar IC50 values [24], further supporting vibralactone as a promising lead compound warranting further investigation. Although vibralactone (6) is a relatively small natural product, its molecular structure features a unique 4/5-fused bicyclic β
- and ClpP2 and it could be utilized as a probe to study the activity and structure of the ClpP1P2 complex from Listeria monocytogenes [25]. Previously, Snider and co-worker reported the first total synthesis of vibralactone (6) employing Birch reductive alkylation, intramolecular aldol reaction and
Conformational effects on iodide binding: a comparative study of flexible and rigid carbazole macrocyclic analogs
Beilstein J. Org. Chem. 2025, 21, 2369–2375, doi:10.3762/bjoc.21.181
- (Figure S3) in Supporting Information File 1. WDG exhibited poor solubility, which hindered the direct acquisition of its single crystal structure for characterization. However, after Boc (tert-butyloxycarbonyl) protection, a single crystal structure (CCDC Number: 2339028) of the modified compound was
- successfully obtained. This indirectly confirmed the molecular structure of WDG [22]. The NH protons of the carbazole moiety in PBG and WDG were observed as singlets at δ 7.9706 and δ 7.8624, respectively, in their 1H NMR spectra (Figure 1a and 1b). In order to study the role and mechanism of anion recognition
Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications
Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179
- ][10][11][12]. Depending on their structure, rotaxanes can be classified by the number of components involved. In [1]rotaxanes, the macrocycle is covalently attached to one end of the axle while remaining mechanically interlocked with another part of the axle (Figure 1) [13][14][15]. In contrast, [2
- based on the location of the photoswitch within the rotaxane structure – either integrated into the axle or situated in the macrocycle. Within these categories, we highlight widely used photoswitches, including acridane, anthracene, azobenzene, cycloheptatriene, dithienylethene, fumaramide, hydrazone
- systems, the azobenzene functions also as a recognition site for macrocycles such as cyclodextrins [18][33][34][35][36][37][38][39], or CBPQT4+ [40][41][42], while in others, it serves merely as part of the axle structure without directly participating in macrocycle recognition. Examples of the latter
Comparative analysis of complanadine A total syntheses
Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178
- enantiomers of 51 allowed Tsukano and co-workers to prepare both enantiomers of complanadine A. Their further biological evaluation of the complanadines and several synthetic intermediates revealed that the pseudo-dimeric structure, absolute configuration, and oxidation level are important for the observed
- catalysis, C–H activation methods, biomimetic synthesis, classic rearrangements, skeletal editing logic, and others. In addition, these efforts enabled the identification of the potential cellular target of complanadine A, validation of its neurotrophic activity, establishment of preliminary structure
Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis
Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177
- structure of septosone B (37) [31] (Scheme 6). All these compounds were first isolated from South China Sea sponges of the genus Dysidea by Lin's group. Dysiherbol A (33) exhibits NF-κB inhibitory activity (IC50 = 0.49 μM) and cytotoxicity against the human myeloma cell line NCI H-929 (IC50 = 0.58 μM
- -diketones, the rigid lattice structure locks molecules into a specific conformation, limiting access to certain γ-hydrogens for abstraction and thus enhancing regioselectivity [42]. Enantiopure 87 was obtained by preparative chiral supercritical fluid chromatography (SFC) resolution of the racemate, while
- -diketones, α-keto esters, α-keto amides, 1,4-quinones, and 1,2-quinones, emphasizing their unique roles in constructing diverse substructures. However, the reaction faces challenges in terms of regioselectivity and stereoselectivity, which are mainly attributed to the influence of substrate structure
Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes
Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176
- methyl substituents (H2). Fortunately, the X-ray crystal structures of G2W1 and G2W3 reported below shed further light on their poor performance as solid state sequestrants. X-ray crystal structure of G2W1 and G2W3 Eventually, we were able to grow single crystals of G2W3 (CCDC 2466611) and solve their
- H2O and TFA are also seen in the crystal structure. At one C=O portal, an H2O molecule engages in H-bonding interactions with one C=O group (O···O: 2.948 Å, H···O: 2.149 Å, O–H···O angle: 163.603˚) and one OMe (O···O: 2.963 Å, H···O: 2.169 Å, O–H···O angle: 159.887°) group. The other C=O portal
- substituents – provides a compelling explanation for the superior performance of H2 over G2W3 and G2W4. We were also fortunate to obtain single crystals of G2W1 (CCDC 2466610) and solve the structure by X-ray diffraction measurements. Crystals of G2W1 are triclinic with the P−1 space group (a/Å = 15.414(4); b
Pathway economy in cyclization of 1,n-enynes
Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173
- Hezhen Han Wenjie Mao Bin Lin Maosheng Cheng Lu Yang Yongxiang Liu Key Laboratory of Structure-Based Drug Design and Discovery (Shenyang Pharmaceutical University), Ministry of Education, Shenyang 110016, P. R. China Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016
- assembled the pentacyclic spiroindole framework 61 (Scheme 13, path b). The controllability of this cyclization process arose from the steric and electronic effects of the aryl group, where the π–π interactions and rigid structure of the aryl group facilitated the stabilization of the five-membered spiro
- allene intermediate 141, which subsequently underwent 5-exo-trig cyclization to construct polysubstituted furan compounds 142. Liu et al. discovered that the regioselectivity of cyclization could be completely altered by introducing a cyclic structure to modify the bond angle of the enol ether
Research towards selective inhibition of the CLK3 kinase
Beilstein J. Org. Chem. 2025, 21, 2250–2259, doi:10.3762/bjoc.21.172
- , examination of the structure of CLK3 shows that this key lysine 241 is very close to the entry of the ATP binding site (Figure 1B). Lysine 241 could be considered as an opportunity to design new molecules with an improved affinity to CLK3, by adding specific interactions with this amino acid bearing a primary
- ). Second, molecular docking using DYRK1A crystal structure was used to understand the unexpected binding on the DYRK kinases (Figure 6). Surprisingly, another lysine (K175) is also located near the acidic group of VS-77 (at 3.2 Å between the carbonyl carbon atom and nitrogen from amine). This residue is
- ) Structure of CLK3 highlighting the lysine in position 241 (PDB ID: 2WU6 [25]). A) Docking of our previous inhibitor (DB18) in CLK3 and B) our working hypothesis. Design of our target molecules. Primary evaluation of the inhibition of the new quinazolines against a short panel of mammalian kinases. Residual
Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates
Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169
- closed vial in which the reaction is carried out does not contain the necessary amount of oxygen. Structure determination of the products was also supported by single-crystal X-ray diffraction in the case of several representatives: 3b, 3d, 3e, 3g, 3h, (E)-7a, 7b, 7d, 7e, (E)-7f, (Z)-7h, 7i, and (E)-9a
- permeability values, meanwhile, most of the gray datapoints with insufficient solubility scattered in the right side of the plot, indicating their high lipophilicity. As part of the discussion on structure–property relationships, most of the compounds with low kinetic solubility showed similarities in their
- structure. It can be clearly seen that the majority of these compounds have at least 4 rings (Table 2). Moreover, all derivatives with a phenyl moiety in position 4 fell into this category (3f–j, 7f–j, (E)-9b, 10b) obviously making the 4-phenyl substituent undesirable. The solubility of compounds is also
A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines
Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168
- twist of the two chromophores of quaternary ammonium salts (S)-2f,g and (R)-2h can be determined from the sign of the Cotton effect in CD. However, it is more difficult to predict the direction of twist from the structure of the quaternary ammonium salts than in the case of the 1–primary amine
- structure analysis was performed on a Bruker SMART diffractometer equipped with a CCD area detector at 120 K. Silica gel 60 F254 precoated plates on glass from Merck Ltd. were used for thin-layer chromatography (TLC). General procedure for the synthesis of conjugates 2a–h (S)-2-[2,10-Bis(4-methoxyphenyl
- based on B3LYP/6-31G* level. Four major conformers of (S)-3f based on B3LYP/6-31G* level. The distribution of conformers of (S)-3a–h against dihedral angles ϕ (C6–C1–C1'–C6') calculated by B3LYP/6-31G*. Crystal structure of (S)-2b. Four conformers exist in the unit cell. Hydrogen atoms are omitted for
C2 to C6 biobased carbonyl platforms for fine chemistry
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- molecule which plays an important role in the biorefining industry. It was first isolated in 1832 by the German chemist Johann Wolfgang Döbereiner, and its structure was determined in 1901 by German chemist Carl Harries. In 1922, the Quaker Oats Company produced furfural on a large scale using oat hulls
The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products
Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164
- stereocenters, two of which are all-carbon quaternary stereocenters. Such a skeletally extraordinary structure poses significant challenges for total synthesis. In 2024, Stoltz and co-workers finished the divergent enantioselective total synthesis of (−)-hunterine A and (−)-aspidospermidine by utilizing a Ru
- sesquiterpenoids, toxicodenanes A–C and E (see representative structure 16 in Scheme 7) were isolated from Toxicodendron vernicifluum in 2013 to 2015 [63][64], whose structures feature the all-carbon bicyclic skeleton and four to seven contiguous stereocenters, posing significant challenges to their synthesis
- quaternary centers isolated from Penicillium cylopium and exhibit various biological properties [68]. The intriguing structure and interesting biological properties have attracted continued synthetic attention [69][70][71]. In a 2023 report, the group of Lee and Han adopted an early-stage desymmetric
Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B
Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162
- reported structures of alkaloids aspera chaetominines A and B have been synthesized. Moreover, the four-step synthesis of the reported structure of aspera chaetominine B generated another diastereomer that was converted in one-pot to (–)-isochaetominine C, which turned out to be the revised structure of
- , we have communicated the revision of the structure of versiquinazoline H to 11. During and after the latter work, we undertook further investigation on the last step of our approach to chaetominine-type alkaloids, namely, the lactamization reaction for synthesizing 3,14-cis-chaetominines and the DMDO
- (–)-isochaetominine A (4) and a diastereomer; 2) the diastereo- or enantiodivergent syntheses of chaetominine-family alkaloids and stereoisomers, and 3) the reported structures of aspera chaetominines A and B (12 and 13) and revised structure of aspera chaetominine B: 6 [(–)-isochaetominine C]. Results and Discussion
Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design
Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161
- biological evaluation of novel indolo[1,2-c]quinazoline derivatives, with a particular focus on their antiproliferative potential against human cancer cells. We introduced structural modifications at positions 5, 6, and 12 of the indolo[1,2-c]quinazoline core to explore the structure–activity relationships
- , offering valuable insights into their SAR and paving the way for a future evaluation of these compounds as anticancer therapeutics. Keywords: antiproliferative activity; antitumor agents; indolo[1,2-c]quinazoline; modification; structure–activity relationship; Introduction Organic compounds featuring
- for more extensive structure–activity relationship investigations. This work represents the first systematic evaluation of the anticancer potential of indolo[1,2-c]quinazoline derivatives, a chemotype previously studied mainly for synthetic accessibility but not for biological activity. Unlike prior
Bioinspired total syntheses of natural products: a personal adventure
Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160
- , people began to be aware of the capability of mankind in making natural organic molecules. Since then, organic scientists are brave to challenge the complex organic structure of natural products given by nature [2][3][4][5]. To achieve the growing structural complexity of natural products, the synthetic
- against P-388 (mouse lymphocytic leukemia). Attracted by the novel bridged structure and in order to further determine the structure, particularly the absolute configurations, we explored the total synthesis of chabranol [19]. Structurally, this molecule contains an oxa-[2.2.1] bridge, with two quaternary
- the structure further, X-ray diffraction analysis of the derivative of bicycle 9 was obtained. This approach established the first total synthesis of chabranol in a concise way through the bioinspired Prins-triggered double cyclization strategy to rapidly construct the bicycle. Total syntheses of
Other Beilstein-Institut Open Science Activities
