Design, synthesis, and biological evaluation of FXR/ASK1 dual-target modulators

• Xi Zhang,
• Jingyan Wang,
• Ziqiang Zhao,
• Caiyi Wang,
• Zenghui Ye,
• Wei-Yuan Ma,
• Jian-Xing Xu and
• Fengzhi Zhang

Beilstein J. Org. Chem. 2026, 22, 771–781, doi:10.3762/bjoc.22.59

• -luciferase reporter assay in CHO cells cultured for 24 hours following addition of GW4064 and test compounds. Compared to the control group, **p < 0.01 and ns indicate no significant difference, with control; DMSO serving as the control group. ASK1 inhibition of all compounds. Results of the ADP-Glo™ kinase

Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• esters, had been obtained from 2-aminopyridines 9a–d while no reaction was observed for 2-aminopyridine 9e (Scheme 1). We reasoned that at the relatively small scale of the reaction (≈350 mg aminopyridine) and because a period of 30 min stirring of all reactants had been allowed prior to addition of the

• taken place before addition of the other reagents. Increasing the amount of acid catalyst to 0.2 equiv significantly increased the yield of the ester products 13, although the yields were still modest (Table 1). A further increase to 0.3 equiv of acid catalyst did not lead to further yield improvement

Synthesis and biological evaluation of new brassinosteroid analogs with C-22 benzoate function

• María Núñez,
• Camila Escobar,
• Mario Párraga,
• Mauricio Soto,
• Luis Espinoza-Catalán,
• Katy Díaz and
• Andrés F. Olea

Beilstein J. Org. Chem. 2026, 22, 753–762, doi:10.3762/bjoc.22.57

• in Table 2. The data indicate that derivatives with a OH group at C-3 (TE analogs) are much more active than derivatives with a carbonyl group in this position (3-DT analogs). However, the addition of another OH group at C-2 (CAT analogs) increases the activity of analogs substituted with p-methyl

• complex mixture of proteins. In addition, it is possible to quantify their expression by using suitable primary and secondary antibodies to visualize it. It has been established that the dephosphorylated forms of BZR1 and BES1, and their concomitant accumulation in the nucleus, control the activity in the

• . However, it seems that on the signaling cascade this structural effect is lost, and the outcome do not follow the initial pattern. It is known that plant cells can synthesize most hormones and, therefore their regulation is decentralized. In addition, each hormone modulates its own synthesis, degradation

Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile

• Melina Goga,
• Hao Zong,
• James Franco,
• Jazmine Prana,
• Rudolph Michel,
• Antonia Muro,
• Elana Rubin,
• Janet Brenya,
• Henk Eshuis and
• Magnus W. P. Bebbington

Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56

• sought confirmation of the structures of the minor and major diastereomers in our own hands. Noting that preparation of sulfides by double conjugate addition of Na2S or NaSH has been widely studied, and that the stereochemical assignments presented therein are in some cases supported by X-ray

• crystallographic studies, we prepared trans-sulfide 2 using an established protocol [23], and then oxidized it to trans-sulfone 1a (Scheme 2). This material was identical to the major product from Rongalite double conjugate addition. Additional confirmation of the structures of major and minor diastereomers 1a and

• (indicated). There is nothing to suggest from the calculations that an inherent reactivity problem prevents the initial addition of Rongalite to the enone, especially given that the singly electrophilic 2,6-dimethylbenzalacetone is known to participate in reactions with conjugate nucleophiles [25]. It is

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

• yields and with high diastereoselectivity and enantioselectivity (up to 97% ee). However, α-(alkylimino)esters were less reactive, requiring longer reaction times and yielding products with slightly lower enantioselectivity (up to 81% ee). In addition to dimethyl maleate, other dipolarophiles, such as

• addition to gem-difluorostyrenes, 1,1,2-trifluorostyrenes can be used in the synthesis, which leads to the formation of 3,3,4-trifluoropyrrolidines in moderate yields and high diastereoselectivity [30]. In addition to the above, the authors demonstrated the broad applicability of this method using

• form pyrrolidine 64. Further treatment of 64 with cinnamaldehyde and N-phenylmaleimide leads to the second (3 + 2) cycloaddition adduct 65. Addition of ICl to 65 results in cyclization involving the styrene groups, which is accompanied by the formation of decahydropyrrolo[2,1,5-cd]indolizine 66. The

Anti-invasive and cytotoxic evaluation of a (+)-pinoresinol-based semisynthetic library against glioblastoma

• Chen Zhang,
• Kah Yean Lum,
• Jonathan M. White,
• Paul I. Forster,
• Nicholas Booth,
• Sunita A. Ramesh and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 691–704, doi:10.3762/bjoc.22.54

• two new pinoresinol ester derivatives 6 and 7 showed the biggest differences to the natural products owing to the addition of UV-active acyl moieties. Owing to our developing interest in identifying natural products and derivatives that are cytotoxic to human cancer cell lines and/or block invasion or

• aliquot (10 µL) of the harvested cells was counted in a haemocytometer after the addition of 10 µL of trypan blue to determine the cell count. The remaining cells were centrifuged at 1,100 rpm for 5 min. Based on the cell count, the spun cells were resuspended in the appropriate volume of complete medium

• addition of an extracellular matrix, such as Matrigel, on top of a porous membrane that allows cells to invade in response to the chemotactic gradient. The transwell assay protocol was adapted from the method outlined by Justus et al. [41]. Corning 6.5 mm transwell assay plates (24 wells) with

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• . Their complex structures and diverse skeletons have continuously inspired chemists to design novel strategies and develop new synthetic methodologies. For the synthesis of complex terpenoid natural products, in addition to those starting from simple and easily available starting materials, Nature has

• the selective late-stage functionalization. In addition, since the precursors for terpene cyclases are general no matter they are provided by the IU pathway or MVA/MEP pathways, a diversity of terpene skeletons would be easily accessible by simply integrating known or newly discovered terpene cyclases

Harnessing light energy with molecules

• Grace G. D. Han,
• Mogens Brøndsted Nielsen and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2026, 22, 680–682, doi:10.3762/bjoc.22.52

• and can be potentially used at a later stage. A strong emphasis is on molecular photoswitches (photochromic molecules) that upon irradiation undergo cis/trans isomerization, intramolecular photocycloaddition, or an electrocyclic reaction. In addition, several articles describe absorption tuning by

• -workers [4], the π-system of monoaryl-substituted NBDs was synthetically extended by acetylenic bridges. In addition, Hebborn, Ihmels, and co-workers [5] show that 19F NMR spectroscopy enables unambiguous identification of mono- and bisQC intermediates in the sequential photoreactions of a fluorinated

• singlet-state photoredox catalyst in the sulfonylation/arylation of styrenes and as a triplet sensitizer in energy transfer catalysis. In addition to the photoredox contribution mentioned above, this thematic issue contains two publications on photochemical reactions beyond photoisomerizations. In the

Using generative AI to transform peptide hits into small molecule leads

• Joshua Mills and
• Yu Heng Lau

Beilstein J. Org. Chem. 2026, 22, 672–679, doi:10.3762/bjoc.22.51

• molecule candidates, providing potential alternatives to traditional computationally expensive physics-based workflows such as docking, MD, and free-energy perturbation (FEP) calculations for affinity estimation. For example, Boltz-2 features a strong emphasis on affinity prediction in addition to its core

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

• Egor N. Boronin,
• Svetlana E. Kaurkina,
• Milena M. Svetlakova,
• Anton S. Bolshakov,
• Maxim V. Arsenyev,
• Vasilii F. Otvagin,
• Alexey Yu. Fedorov,
• Timothy Noël and
• Alexander V. Nyuchev

Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50

• processes. Umemoto and Togni reagents display low atom efficiencies in addition to very high costs. Taken together, these considerations indicate that TFA and TFAA represent the most attractive choices from both ecological and economic perspectives. In the selection of solvents for photochemical

• that the addition of the electrophilic CF3 radical to the aromatic ring may differ in energetic profile between the two substrates (Scheme 5). However, DFT calculations showed that the thermodynamic parameters for both processes are comparable, indicating that other elementary steps may be responsible

• substrates are shown in Supporting Information File 1. Radical trapping reactions. Proposed mechanism. Addition of CF3 radical to benzene and TMB. Comparison of atom efficiency and prices of the CF3 sources.a Optimization of reaction conditions. Scaling-up of the trifluoromethylation of TMB. Supporting

Advantages of PROTACs in achieving selective degradation of homologous protein families

• Luxi Yang,
• Xinfei Mao,
• Jingyi Zhang,
• Jing Shu,
• Wenhai Huang,
• Xiaowu Dong,
• Yinqiao Chen and
• Mingfei Wu

Beilstein J. Org. Chem. 2026, 22, 628–661, doi:10.3762/bjoc.22.49

• , Hangzhou 310053, China College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China 10.3762/bjoc.22.49 Abstract Proteolysis-targeting chimeras (PROTACs) have emerged as a promising therapeutic modality and now represent an important addition to the toolkit of medicinal chemists

• are mainly involved in transcriptional regulation. However, the biological functions of CDK10, 11, 14–18, and 20 have not been fully elucidated [45][46]. CDKs are essential in cell proliferation, transcriptional activity, and neuronal activity [44]. In addition, disorders of these protein kinases

• and E3 ligand when designing PROTACs with high selectivity to target the degradation of CDK6. However, some studies did not support this hypothesis. When considering the influence of the linker on PROTAC selectivity, attention must be paid to the composition of the linker in addition to its length. In

Hydrogen production from formic acid catalyzed by NHC–Cu complexes

• Orlando Santoro and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2026, 22, 620–627, doi:10.3762/bjoc.22.48

• realization of a hydrogen economy [6][7]. Amongst the various H2 sources investigated to date, formic acid (HCO2H, FA) is considered one of the most promising. Indeed, FA contains 4.4% H2, is inexpensive and is liquid under ambient conditions, thus easy to handle and transport. In addition, the CO2 generated

• ][29] and Rh [30][31] have shown to allow the selective transformation of formic acid into H2 and CO2 with high turnover frequencies (TOFs). In most cases, addition of a base (either amines or formate salts) is required to obtain high catalytic activity. Efficient systems based on inexpensive metals

• formate products. Excess H2 can be generated by dehydrogenative coupling of those species in the presence of the copper catalyst. Indeed, metal hydride systems have shown high catalytic activity in such a reaction [59][60]. In addition, the formation of products compatible with the polymerization of

Towards the targeted protein degradation of CK2: design and synthesis of CAM4066-based PROTACs

• Sophie Day-Riley,
• Sona Krajcovicova,
• Aryaman Raj Sokhal,
• Jan L. Venne,
• Paul Brear,
• Marko Hyvönen,
• Benjamin C. Whitehurst,
• Jason S. Carroll and
• David R. Spring

Beilstein J. Org. Chem. 2026, 22, 611–619, doi:10.3762/bjoc.22.47

• itself is a moderately polar molecule, and linker addition further increases polarity. Collectively, these proof-of-concept results highlight the complexity of designing bivalent molecules for CK2 degradation and underscore the need for further optimisation of warhead potency, linker length, exit vector

Computational prediction of C–H hydricities and their use in predicting the regioselectivity of electron-rich C–H functionalisation reactions

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2026, 22, 603–610, doi:10.3762/bjoc.22.46

• -catalysed C–H carbamoylation of the cis-fused azabicyclo[4.3.0]nonane derivative 9, and Overman and Tomasi [46] reported the Cu(II) salt-catalysed addition of a N-tosyl group to the C–C double bond in compound 10 in conjunction with an H-abstraction, to form a new C–C double bond. In all three cases, the

• , 7, and 9) indicating that hydricities offer a valuable measure of reactivity in addition to BDEs for these types of reactions. Conclusion We have developed HAlator, an automated QM-based workflow for computing C–H hydricities, benchmarked against 35 experimental values in DMSO to yield an MAE of

Continuous-flow carbonyl hydrogenation under subatmospheric to atmospheric hydrogen pressure enabled by robust heterogeneous Pt–Fe catalysts

• Hiroyuki Miyamura,
• Ryosuke Kajiyama,
• Shun-ya Onozawa,
• Yoshihiro Kon and
• Shū Kobayashi

Beilstein J. Org. Chem. 2026, 22, 575–582, doi:10.3762/bjoc.22.43

• heterogeneous catalysts are used in a continuous-flow system, the catalyst included in a column allows semi-permanent use without recovery and reuse operations that are usually needed in a batch system. The integration of multiple column reactors also enables multistep continuous production. In addition, an

• conditions is adaptable to sustainable chemical synthesis, minimizing energy consumption and enabling the use of green hydrogen. In addition, the newly obtained insights regarding the relationships among the Fe/Pt ratios in the catalysts, the bimetallic structure, and the resulting catalytic performance for

Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis

• Catherine Gsell,
• Philipp Rebmann,
• Karina Opara,
• Christine Beuck,
• Peter Bayer,
• David Bier,
• Ingrid R. Vetter and
• Thomas Schrader

Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41

• ) Peptide tweezer conjugates 1 and 2a with triazoles linking the tweezer and H3 peptide at its C-terminus. Note that both azidopropylamine as well as azidoornithine establish almost the same distance between peptide and tweezer. In addition, they place the tweezer into the vicinity of the phosphorylated

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• Duesseldorf, Germany Integrative Taxonomy of Plants, Friedrich-Schiller-University Jena, 07743 Jena, Germany Senckenberg Institute for Plant Form and Function (SIP) Jena, 07743 Jena, Germany National Tropical Botanical Garden, 3530 Papalina Road, Kalaheo, HI 96741, USA 10.3762/bjoc.22.39 Abstract In addition

• isolated from a dichloromethane extract of leaves of Melicope barbigera A. Gray, a species endemic to the island of Kaua’i, Hawaiian Islands [2][3]. In addition, small amounts of two tetracyclic citrans were identified as a 30:70%-mixture of isomeric melifoliones A (1), and melifolione B (2) [1], both

• ), but the yield was less than 5% and therefore of no preparative interest. The best results to get melifolione B (2) were achieved by briefly heating 5 in a closed microwave apparatus without solvent at 130–140 °C after addition of catalytic amounts of acetic acid. By this procedure, the proportion of 2

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• variation often leads to a red-shifted absorption, the half-lives of the corresponding quadricyclanes are often decreased at the same time. In particular, the addition of an acetylene unit between the linking aromatic part and the norbornadiene often leads to short half-lives [29][30][31]. As arene-linked

• the photoreaction by absorption spectroscopy revealed the formation of a new maximum at 235 nm with no discernible isosbestic points, clearly indicating the presence of more than two differently absorbing compounds (Figure 2). In addition, the examination of the photoreaction with 1H NMR spectroscopy

• ]. Upon addition of magic blue (5, 7.5 mol %) to a solution of quadricyclane 2f0,3 in CDCl3, the norbornadiene 1f was formed almost quantitatively in addition to very small traces of tri(4-bromophenyl)amine, i.e., the reduced catalyst (see Supporting Information File 1, Figure S12). Discussion A

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• metathesis with ethyl acrylate, acidic cleavage of the diol protecting group and addition of NaH induced the oxy-Michael reaction towards 18 in 4:1 dr. Reduction of the ester moiety, subsequent protection with TBDPSCl and methylation of the secondary alcohol furnished 19. After Bn-deprotection, iodination

• and addition of vinylmagnesium bromide, 21 was received and dihydroxylated towards 22 in 5:1 dr. The second path towards 27 commenced with the assembly of 23 from 14 via Bn-protection, following oxidation and Horner–Wadsworth–Emmons (HWE) reaction (Scheme 3). Stereospecific vinylation with a Gilman

• cuprate and acidic treatment afforded 25 in 13:1 dr. After protection with 2,6-DCBCl, reduction with LiAlH4, TBDPS-protection and methylation, 26 was received in 35% yield. Eventually, the addition of I2 triggered an iodocyclization towards 27. While in the first sequence only mg amounts of 22 were

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• carboxylic acid derivatives such as esters, acyl chlorides and anhydrides with hydroxylamine salts [41]. A variety of coupling or activating agents were also employed in case of simple addition of hydroxylamine to carboxylic acid compounds [42][43][44]. In addition, alternative methods starting from

• calixarene tetraethylacetate [53]. In the original procedure, KOH was added at −5 °C, and the mixture was stirred for 5 hours at this temperature, followed by 5 days of stirring at room temperature. In our hands, both the addition of KOH and stirring were performed entirely at room temperature, and 1H NMR

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• remote biaxial chiral ligands 21 (Scheme 4) [45]. These ligands were successfully applied in asymmetric hydrogenation, revealing dual asymmetric induction effects and enriching the design principles for chiral catalytic systems. In addition, Yan’s group developed an organocatalytic strategy for the

• yields, indicating potential utility in chiral fluorescent materials. In addition, Du’s group reported an N-heterocyclic carbene (NHC)-catalyzed (3 + 3) cycloaddition of 2,6-disubstituted alkyne esters 38 with 6-aminouracils 39, affording distal biaxial uracil frameworks with both C–C and C–N chiral axes

Structural reassignment of compound 968, an allosteric glutaminase inhibitor

• Lindsey A. Albertelli,
• Sainabou Jallow,
• Chun Li and
• Scott M. Ulrich

Beilstein J. Org. Chem. 2026, 22, 455–460, doi:10.3762/bjoc.22.33

• aldehyde, followed by conjugate addition and cyclo-condensation with a 1,3 dinucleophile. Members of this reaction family are variations on the Biginelli and Hantzch reactions, where the dinucleophile is urea and the ammonia adduct of a second equivalent of the dicarbonyl, respectively [31]. A similar

• solution of the test compound in DMSO or DMSO itself was added (1 µL), mixed by gently pipetting up and down, then incubated for seven minutes at room temperature. The glutaminase reaction was initiated by addition of 20 µL of a solution of glutamine (100 mM) and K2HPO4 (500 mM), then mixed by gently

• pipetting up and down and incubated at room temperature for seven minutes. The reactions were quenched by addition of cold 3 M HCl (10 µL). An aliquot (10 µL) of each quenched GAC reaction was added to 190 µL of a glutamate dehydrogenase reaction which consisted of a solution containing Tris-HCl (100 mM, pH

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• favorable to catalyze the Darzens reaction [31][33], and some commonly used Lewis acids (Table 1, entries 17–22) were studied. The results showed that the addition of catalytic amounts of Lewis acids remarkably accelerated the reaction which was completed within 4 h while the yield was not affected. Among

• following step. Lastly, hydroxy deprotection and cyclization of (±)-4a using aqueous HBr solution (40%, 12.0 equiv) in MeOH/THF afforded 4.56 g of trans-(±)-taxifolin accounting for 41% yield starting from 2. Overall, the scale-up reaction proceeded smoothly with comparable yield. In addition to the

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• methylseleninic acid (1) has emerged as a promising drug candidate for the treatment of triple-negative breast cancer (TNBC) [27]. In addition, the classical organoselenium compound diphenyl diselenide (2) has shown significant anticancer activity against the MDA-MB-231 breast cancer cell line [28]. Very recently

• washed twice with water (20 mL) and brine (20 mL). The organic layer was dried over anhydrous MgSO₄, and the solution was concentrated under reduced pressure. Slow evaporation of the solvent followed by the addition of methanol afforded the desired compound 10 as a white solid with a yield of 1.2 g, 53

• . X-ray data Table 3 shows the X-ray data of compound 7. In addition, a packing diagram of compound 7 in the crystal can be found in Figure S20 in Supporting Information File 1. Computational details All computational calculations were carried out using the Gaussian 16 (g16) program [76]. Geometry

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• bis(trimethylsilyl)amine (HMDS) with n-butyllithium in THF immediately before the addition of a propargylated calixarene followed by TBSCl. This allowed us to improve the yield of the known calix[4]arene 6 [9] having four silylated propargyl groups at the narrow rim, and to obtain the respective

• flexible linkers between the calixarene core and the differently arranged triazole heterocycles. In addition to what could be interpreted as a set of signals from homodimer 472, a set of broadened resonances was observed in the spectrum (Figure 6c). Neither prolonged heating of the sample at 50 °C before

• 1H NMR spectra of monomers 47 and 48 could be detected upon addition of the salt. Attempts to conduct the experiment using solid–liquid extraction in neat CDCl3 were also unsuccessful, since no changes in the 1H NMR spectrum of capsule 472 were detected upon the addition of excess solid Zn(ClO4)2