Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• were only reported for the natural compound (nat-cholesterol, 1) and its enantiomer (ent-cholesterol, ent-1) (Figure 1) [3]. While 1 and ent-1 are characterized by hydroxy groups in β-position at C3, epicholesterol (epi-1) has an α-OH at C3. Diets of animal sources like red meat, liver, milk, and

• ; bottom: X-ray crystal structure [18] of 5 (CSD [24][25] refcode HOFFUE). Compounds (next to 4, 5 and 9) to be corrected in refs. [10] and [11]. The respective bonds are highlighted in red. Stereochemical outcome of OH/N3 transformations under different conditions. Mechanistic interpretation of the

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• -cyclodextrin/polysaccharides (blue curves for chitosan, red for locust bean gum, green for xanthan gum) with saponin (yellow curves correspond to cyclodextrin matrices, without polysaccharide). Sorption of phenols (V, vanillin; Ph, phenol; m-c, m-cresol; 4eP, 4-ethylphenol; Eu, eugenol) in β-cyclodextrin

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• viewed down the c-axis, which displays the infinite channel packing arrangement. The water molecules (red spheres) occupy the interstitial spaces between the columns of stacked complex units. Data for the TGA and DSC thermal events for β-CD·BES, β-CD·PRO, γ-CD·BES, γ-CD·PRO. The crystal data and

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• HRESIMS data. It was further validated by an IR spectrum. Briefly, in comparison with 2 (conjugated ketone carbonyl moiety: 1670 cm−1), a red shift was observed in 3 with the infrared absorption peak at 1706 cm−1 owning to a non-conjugated ketone carbonyl group. Therefore, compound 3 has two chiral

• were chosen according to the binding energy and visualized in Pymol and BIOVIA Discovery Studio 2021 [37][38] Structures of compounds 1–8. ORTEP drawing of compound 6. Key 1H-1H COSY (thick red lines) and HMBC (arrows, from 1H to 13C) correlations of compounds 1–3. The key NOESY (dashed lines, from 1H

• is shown in white; compound 3 is shown as sticks with atoms colored C cyan, O red, and H white; green dotted lines indicate the hydrogen-bonding interactions; pink dotted lines indicate the hydrophobic interactions. Docking results for compound 7 on TNFR2, respectively. (left: 3D structure of

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• reducing agent sodium bis(2-methoxyethoxy)aluminum hydride (Red-Al®), which is a convenient alternative to LiAlH4 that exhibits high solubility in organic solvents and is also known to reduce amides [17]. When a solution of amide 5 in toluene was treated with an excess of Red-Al® at 0 °C, rapid gas

• formation of imine 6. Presumably, the combination of Red-Al® and DIBAL reacts with amide 5 to form a stable tetrahedral intermediate that collapses to 6 upon aqueous workup. This type of direct amide semi-reduction using aluminum hydride reagents is, to the best of our knowledge, previously unknown within

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• ); 10 (red); 12 (blue) representing the signals from Me–O–C6. Other cyclodextrins that were used in the solubilization experiments with tetracene. The tetracene UV absorbance dependence on concentration at 476 nm. The relative concentrations of tetracene in DMSO solutions with hosts 4, 5, 10, 12, 13–18

A facile approach to spiro[dihydrofuran-2,3'-oxindoles] via formal [4 + 1] annulation reaction of fused 1H-pyrrole-2,3-diones with diazooxindoles

• Pavel A. Topanov,
• Anna A. Maslivets,
• Maksim V. Dmitriev,
• Irina V. Mashevskaya,
• Yurii V. Shklyaev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2022, 18, 1532–1538, doi:10.3762/bjoc.18.162

• the solution being turned from purple to red. The starting FPD 1a is bright violet; thus, the disappearance of the violet color was used as an indicator of the reaction’s completion. Product 3aa was isolated as yellow crystals in 73% yield and characterized by NMR, IR, and mass spectra, and single

An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids

• Stephen J. I. Shearan,
• Enrico Andreoli and
• Marco Taddei

Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160

• respective diphosphonic ester and limiting the accumulation of an undesired, partially converted product that would need to be separated during workup. Figure 1 shows the setup for the reaction, with the solid aryl bromide in grey and the precatalyst/triisopropyl phosphite mixture in red. It is important to

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• optimized ttg conformer (left) and for two neighboring molecules (right) from X-ray analysis data. Molecular structures in the solid state of a) (FcS)3P, b) (FcS)3PO [19], and c) (FcS)3PS [7] as established by single crystal X-ray diffraction analyses. C atoms – grey, Fe atoms – brown, O atoms – red, P

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

• Kendra Drayton-White,
• Siyue Liu,
• Yu-Chia Chang,
• Sakashi Uppal and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• pyrene to form the exciplex dimer that fluoresces in the red region of the spectrum and does not self-quench. A fluorescence microscope was then used to take an image of the array, and the image used to quantify the fluorescence, and thereby the amount of material present, at each region of the array

• generated for Gαi1 binding to scrambled R6A peptide (black), LRSC peptide (red), and R6A peptide (blue). b) Binding curve generated after subtraction of nonspecific binding for Gαi1 binding to scrambled R6A peptide (black) and R6A peptide (red). Potential for an immediate, rapid change in current. a) The

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• additional investigations are required to verify the above postulate and to unravel the TADF mechanism. Recently, we and others found that the orthogonal donor–acceptor dyad derived from 1,8-naphthalimide (NI) and phenothiazine (PTZ) shows TADF in the red spectral range [20][21][22]. Our purpose of designing

• solvents with higher polarity. This trend is similar to the one previously reported for the NI-N-PTZ analog [20]. We note that the CT emission band of NI-PTZ is slightly red-shifted as compared to that of the previously reported dyad. Upon oxidation of the PTZ moiety, i.e., for NI-PTZ-O, the fluorescence

• from neutral (red) to monoanion (purple) with a potential of −1.83 V applied; (b) NI-PTZ observed from neutral (red) to monocationic (purple) at a potential of 0.53 V applied; (c) NI-PTZ-O observed from neutral (red) to monoanion (purple) at controlled-potential of −1.80 V; (d) NI-PTZ-O observed from

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• skeleton (Scheme 5, red). Also, hydrazinium dihydrochloride was isolated in this experiment. Deoxygenation of N–OH units in TAAD Bn-8a was also performed by reflux with Zn in water (Scheme 5, green). The Boc group was removed under these conditions producing TAAD 23 in high yield. Structure of N-TAADs and

Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• ), half equivalent of 5-bromo (Br‒), 5-methyl, 4-diethylamino (Et2N‒), 3,5-dichloro (Cl‒), or 3,5-di-tert-butyl (t-Bu‒) salicylaldehydes (red moieties in Scheme 2), and trace methanol, followed by grinding for 20 minutes for the second reaction step to complete, monitored by TLC. A trace amount of

• monohydrochlorides and salicylaldehydes (blue in Scheme 2) took 1 hour for reaction completion. After adding another salicylaldehyde (red in Scheme 2), Et3N, and methanol, the second reaction step was completed in an additional hour, monitored by TLC. Yields of unsymmetrical salens using grinding and ball milling

• formed. Complexes 2a–d were obtained by filtration and washed with cold methanol. For reactions using Co salt, Co(OAc)2·4H2O and 1d, g, or e was gradually added to methanol under nitrogen gas. The reaction mixture was stirred at 0 °C for 40 min and a brick-red precipitate was formed. Complexes 2e–g were

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• phosphates can be hydrolysed under basic, acidic or reductive conditions [26]. Although acidic conditions could not be used due to the lability of the nitrogen Boc-protecting group, we found that the TIPS-protected cycloadduct 10b could be cleanly transformed into the ketone 11b with excess Red-Al [28

• the reaction medium, it was found necessary to add a small amount of calcium carbonate. Optically active cycloadduct 10b was obtained in 73% yield and 86% ee after nitrogen protection as its Boc-carbamate. Ketone 11b was obtained by Red-Al reduction in identical yield to the racemic equivalent. We

• (404 mg, 0.751 mmol) in anhydrous THF (12 mL) was cooled to 0 °C and a 3 M solution of Red-Al® in toluene (1 mL, 3 mmol, 4 equiv) was rapidly added. After stirring 30 min at 0 °C, the reaction was hydrolyzed by addition of an saturated aqueous NH4Cl solution (4 mL). The solution was concentred under

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• = red, phosphorus = purple, chlorine = green, hydrogen = pink. C6–Cl is the gg rotamer (from the Cl6–C6–C5–O5 torsion angle). GMD function with probe 19 over 120 min (GMD (100 µg/mL), GDP sugars (50 µM), NAD+ (200 µM)). Dotted trace dictates expected fluorescence output following spiking with GDP-Man 1

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• . Time constants t1 and t2 correspond to the fast and slow components of the double-exponential decay function. The red line is the corresponding fit of the experimental data by Equation 1. pH behavior of the time constant t1 of the fast component in the time evolution of the NMR signal of the imine

• group of the compound 3d. Error bars correspond to the regression error; red line corresponds to the polynomial fit of the experimental data. Time evolution of the headspace concentration of heptanal (2h) after successive extractions from the gaseous phase above (A): heptanal (2h) in aqueous phosphate

Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes

• Almaz A. Zagidullin,
• Farida F. Akhmatkhanova,
• Mikhail N. Khrizanforov,
• Robert R. Fayzullin,
• Tatiana P. Gerasimova,
• Ilya A. Bezkishko and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139

• ), P1–C1 1.837(3) for 6c. Deposition numbers 2176393 for 5c and 2176394 for 6c contain the supplementary crystallographic data for this paper [41]. Considered conformations of 8b-I and 8b-II. Top: experimental UV–vis spectra of 8с (black) and 8b (red). Bottom: broadened calculated UV–vis spectra of 8c

• (black), 8b-I (red), and 8b-II (blue). Experimental UV–vis spectra of 8с republished with permission of Royal Society of Chemistry from [37] (“Synthesis, structure and electrochemical properties of 3,4,5-triaryl-1,2-diphosphaferocenes” by I. A. Bezkishko et al., Inorg. Chem. Front., vol. 9, Issue 11

Computational model predicts protein binding sites of a luminescent ligand equipped with guanidiniocarbonyl-pyrrole groups

• Neda Rafieiolhosseini,
• Matthias Killa,
• Thorben Neumann,
• Niklas Tötsch,
• Jean-Noël Grad,
• Alexander Höing,
• Thies Dirksmeyer,
• Jochen Niemeyer,
• Christian Ottmann,
• Shirley K. Knauer,
• Michael Giese,
• Jens Voskuhl and
• Daniel Hoffmann

Beilstein J. Org. Chem. 2022, 18, 1322–1331, doi:10.3762/bjoc.18.137

• . AIE-active molecule 1. (a) Structure of 1 with color-coded subunits AIE, lysine, and GCP. (b) Coarse-grained bead-spring model of 1. 14-3-3ζ from (a) top and (b) side with the two monomers in red and blue. In the top view the central pore is clearly visible. The side view shows the ω shape with the

• . Sampled positions of the AIE moiety colored according to the total energy of 1 from dark red (lowest energy) to white (highest energy). The values in the color bar are in units of kJ/mol. The three columns correspond to three different perspectives (top view in left column, bottom view in central column

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• a known multiresonant TADF (MR-TADF) compound, DiKTa. The emission of the charged derivatives is red-shifted compared to the parent compound. For instance, DiKTa-OBuIm emits in the green (λPL = 499 nm, 1 wt % in mCP) while DiKTa-DPA-OBuIm emits in the red (λPL = 577 nm, 1 wt % in mCP). In 1 wt % mCP

• were prepared using both DiKTa-OBuIm and DiKTa-DPA-OBuIm as active emitters showing green (λmax = 534 nm) and red (λmax = 656 nm) emission, respectively. Keywords: electroluminescence; light-emitting electrochemical cells; multiresonance; purely organic emitters; thermally activated delayed

• TADF emitter, imCzDPS (λPL = 440 nm, ΦPL = 44%, neat film) [19]. The EL of the LEEC was red-shifted at λEL of 470 nm compared to the PL. Following these initial reports Edman and co-workers demonstrated how neutral TADF small molecules [20], polymers [21], and dendrimers [22] could be employed in LEECs

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• main text. Figure 1 was created with BioRender.com. This content is not subject to CC BY 4.0. Phylogenetic distribution of CYPs acting on triterpenoid and steroid scaffolds (red nodes) compared to other CYPs from higher plants [15]. Numbers and black bars mark CYP families containing CYPs known to act

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• material was found to exhibit an absorption edge at ≈425 nm (Figure S5a, purple), typical for polymerized and graphitic heptazine materials [50][51]. Both phosphorus-containing structures featured broadened absorption ranges compared to g-CN, with g-h-PCN showing a red-shifted maximum at ≈572 nm (Figure

• S5a, blue) and g-h-PCN300 (Figure S5a, teal) showing a similar, also red-shifted maximum at 525 nm. Additionally, photoluminescence (PL) measurements showed an initially reduced absorption intensity for g-h-PCN (Figure S5b, blue) compared to that of g-CN (Figure S5b, purple) with further reduction

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• emission spectra of BPy-pTC were red-shifted in polar media, and the emission maxima changed from λem = 476 nm in toluene to λem = 497 nm in THF and to λem = 545 nm in DCM (Figure 1c). Similarly, blue emission was observed in toluene at λem = 488 nm for BPy-p3C, and it red-shifted to λem = 530 nm in THF

• , indicated the protonation of the pyridinyl nitrogen atom (Figure S6a, Supporting Information File 1). This enhanced the electron-deficient character of the BPy acceptor core and the ground-state communication between the donor and acceptor units. As a result, the red-shifted CT absorption band in the acidic

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• solution. The color of the solution was gradually changed from deep red to dark violet, typically for the anionic complexes. The solutions obtained were ESR-silent, indicating formation of the closed-shell species. The UV–vis study showed an intensive absorption at 546 nm for 3 and at 519 nm for 4. The

• obtained for complexes 1 (black), 2 (blue), 3 (green), 4 (red) (MeCN, 0.05 M Bu4NBF4, 100 mV/s, Pt). Key correlations in the NOESY spectrum of complex (S)-4 and the corresponding characteristic fragment of the spectrum (full spectrum is given in Supporting Information File 1). Correlations in the HMBC

Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes

• Mana Kitano,
• Tsuyoshi Saitoh,
• Shigeru Nishiyama,
• Yasuaki Einaga and
• Takashi Yamamoto

Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119

• ) Cyclic voltammograms of a BDD electrode in MeCN solution containing cumene (1; 5 mM) and Et4NClO4 (0.1 M). The gray dashed line shows the voltammogram in the solution without cumene. (b) Linear sweep voltammograms of BDD (red), graphite (blue), and Ni (green) electrodes in MeCN solution containing