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

• 1H NMR spectroscopy. Subsequent measurements of the aqueous solubilities of the four complexes confirmed significant solubility improvements effected by encapsulation of the steroids within the CDs, yielding solubility enhancement factors for BES and PRO in the approximate range 5–20. Keywords

• derivatised CDs containing BES and PRO, thus confirming the sustained interest in this approach and its significance in drug delivery. Previous studies of the complexation of BES, PRO and related compounds by CDs in the solution phase have typically reported the use of NMR spectroscopy to investigate complex

• γ-CD·BES, which diffracted very weakly. Host–guest stoichiometric determination by 1H NMR spectroscopy The host–guest stoichiometries for these complexes were unambiguously determined via solution-state 1H NMR spectroscopy, the samples for the analyses being the complex product materials produced

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• isolated in 41% yield [43] while cyclohexenone 18 was not observed in the crude reaction mixture (as analyzed by 1H NMR spectroscopy). Even though the mechanism was not investigated, the presence of oxygen during the rearrangement step was suspected to account for the oxidation of the enolate intermediate

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

• a tertiary alcohol. The structures of compounds (+)-1 and (+)-2 were elucidated through a combination of HRMS and NMR spectroscopy, while the relative configuration of each compound was established through nuclear Overhauser effect (NOE) correlations. Additionally, the absolute configuration of each

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

• or TOF. The drying and nebulizer gas was nitrogen. High-resolution mass spectra were measured with an Agilent Technologies 6530 Accurate-Mass Q-TOF LC/MS spectrometer. Samples were ionized by electrospray technique (ESI) and detected by quadrupole or TOF. UV–vis spectroscopy spectra were measured

Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• synthesized compound 1 agreed with those of natural 1. At this stage the confirmation of the identity of natural and synthesized compounds by structural determination using NMR spectroscopy is often difficult because the NMR spectra of peptidic products vary depending on the conditions in the NMR tube [25][26

Efficient synthesis of aziridinecyclooctanediol and 3-aminocyclooctanetriol

• Emine Salamci and
• Ayse Kilic Lafzi

Beilstein J. Org. Chem. 2022, 18, 1539–1543, doi:10.3762/bjoc.18.163

• in 90% yield. Thus, the dimesylate 8, which is one of the most relevant precursors for the synthesis of aminocyclitols, was synthesized from the diol 7. The structure of compound 8 was assigned on the basis of NMR spectroscopy. In the 1H NMR spectrum, we observed that methyl signals of the mesylate

• the diazide 9 (Scheme 2). However, the product was determined to be the azidomesylate 10 instead of the expected diazide 9 based on NMR spectroscopy. The position of the azide functionality in 10 was determined from its COSY spectrum. The diagonal peak at 3.97 ppm has cross peaks with the protons

• a positive NOE clearly indicates that the protons H-2/H-7 should have a cis configuration relative to the protons H-1/H-8. Finally, benzyl deprotection with BCl3 of 14 afforded the product 16 in 84% yield. The structure of 16 was assigned on the basis of NMR spectroscopy. Conclusion In summary, we

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

• Arisu Koyanagi,
• Yuki Murata,
• Shiori Hayakawa,
• Mio Matsumura and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

• by 1H NMR spectroscopy, phenylbenzimidoyl chloride (17) was observed to be generated (Scheme 3a) (see Supporting Information File 1 for details). When o-aminophenol (1a) was reacted with 17 [41] in a 1:2 ratio, product 8a and diphenylbenzamidine (18) were obtained in 81% and 86% yields, respectively

Synthesis of the biologically important dideuterium-labelled adenosine triphosphate analogue ApppI(d₂)

• Petri A. Turhanen

Beilstein J. Org. Chem. 2022, 18, 1466–1470, doi:10.3762/bjoc.18.153

• (d2) opens possibilities to quantitative measurements of ApppI in biological samples by mass spectrometry. The synthesized target compound ApppI(d2) was purified by high-performance counter current chromatography and characterized by 1H, 13C, and 31P NMR spectroscopy as well as high-resolution mass

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

• recorded with an Agilent 8453E UV–vis spectrophotometer (Agilent Technologies Inc., USA). Samples were deaerated with N2 for ca. 5 min before measurement and the N2 atmosphere was kept during the measurements. Nanosecond transient absorption spectroscopy The nanosecond transient absorption spectra were

Sinensiols H–J, three new lignan derivatives from Selaginella sinensis (Desv.) Spring

• Qinfeng Zhu,
• Beibei Gao,
• Qian Chen,
• Tiantian Luo,
• Guobo Xu and
• Shanggao Liao

Beilstein J. Org. Chem. 2022, 18, 1410–1415, doi:10.3762/bjoc.18.146

• basis of 1D and 2D NMR spectroscopy as well as high-resolution mass spectrometry. The absolute configuration of 1 was established by ECD calculation. Compounds 2 and 3 represent rare examples of naturally occurring 9,9'-bisnorlignans. All the isolated compounds were assayed for their inhibitory effects

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

• – cinnamaldehyde, cyclamen aldehyde, lilial, benzaldehyde, anisaldehyde, vanillin, hexanal, heptanal, citral, and 5-methylfurfural. Subsequently, the rate of release of the volatile compound from selected pro-fragrances, as a function of the environment (solvent, pH), was studied by 1H NMR spectroscopy (for

• stability towards hydrolysis. Kinetic studies of the imine hydrolysis by NMR For the kinetic studies of the hydrolysis of imino-CDs, we selected the pro-fragrance 3d made from the most common aldehyde – benzaldehyde. The release of the benzaldehyde (2d) was studied by 1H NMR spectroscopy. Aqueous 0.1 M

• phosphate buffer solutions of pH 1.08, 2.00, 3.00, 4.00, 5.00, 6.00, 7.00, 8.00, 9.00, 10.00 11.00, 12.00, and 12.80 were prepared (see Experimental section) using deuterium oxide instead of water to facilitate NMR spectroscopy experiments. Because of the low solubility of the pro-fragrance in water, it had

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

• bromides from one starting aryl aldehyde. Diethyl phosphite was allowed to react with appropriately substituted benzaldehydes in THF for 48 hours at 25 °C to afford diethyl (hydroxy(aryl)methyl)phosphonates 1, which were detected by 31P NMR spectroscopy in THF (21.4 ppm for 1a, 21.0 ppm for 1b, and 21.5

• confirmed by 31P, 1H, and 13C NMR spectroscopy. The 31P{1H} NMR spectra of phosphonium bromides 6 showed a singlet at about 40 ppm, which is typical for phosphonium salts. The 13C{1H} NMR spectra consisted of a doublet at about 20 ppm, corresponding to the carbon atom C1, which is characteristic for the sp3

• (Scheme 3). The structure of 3,4,5-triaryl-1,2-diphosphaferrocene 8b was confirmed by 31P, 1H, and 13C NMR spectroscopy. The 31P{1H} NMR spectrum of 8b showed a singlet at about −10 ppm, shifted upfield by about 210 ppm in comparison to the starting 1,2-diphospholide anion 7b. In the 1H NMR spectra

B–N/B–H Transborylation: borane-catalysed nitrile hydroboration

• Filip Meger,
• Alexander C. W. Kwok,
• Franziska Gilch,
• Dominic R. Willcox,
• Alex J. Hendy,
• Kieran Nicholson,
• Andrew D. Bage,
• Thomas Langer,
• Thomas A. Hunt and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2022, 18, 1332–1337, doi:10.3762/bjoc.18.138

• mol %), Ar atm., 60 °C, 18 h, unless otherwise noted. Isolated yields are reported. a1.0 mmol scale. bHBpin (5.5 equiv). c80 °C. d40 °C. a) Proposed mechanism; b) H-B-9-BBN-catalysed heptanenitrile hydroboration (yield determined by 1H NMR spectroscopy using 1,3,5-trimethoxybenzene as an internal

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

• synthetic strategy, which itself was synthesized from Br-DiKTa [28] following a Buchwald–Hartwig coupling. Details of the synthesis are found in Supporting Information File 1. The identity and purity of the molecules were verified using a combination of 1H and 13C NMR spectroscopy, high resolution mass

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• nitrogen intermediate, see Scheme S1 in Supporting Information File 1). In any case, the N7-ferrocenoylation of adenine anion 3 is a viable process, as demonstrated by the 1H NMR spectroscopy evidence (see above), and by the isolation of the N7-ferrocenoylated product. We have continued our study with an

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• (mechanophores) embedded along the polymer chains (Figure 1a) [1][2][3][4]. This is mostly accomplished through pulsed ultrasonication, and to a lesser extent by single-molecule force spectroscopy techniques [5][6]. The second approach habitually makes use of ball milling techniques to bring together small

• -known mechanophore that generates diarylacetonitrile radicals under force. Hence, when TASN derivative 8, bearing diarylurea moieties, was ball milled, the corresponding radical 9 was detected by electron paramagnetic resonance (EPR) spectroscopy. Similar treatment proved that 6 was 28 times less prone

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

• , mechanochemical synthesis of phosphorus-bridged heptazine-based carbon nitrides (g-h-PCN). The structure of these materials was determined through a combination of powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), 31P magic angle spinning nuclear magnetic resonance (MAS NMR), density

• functional theory (DFT) and electron energy loss spectroscopy (EELS). Compared to traditional furnace-based techniques, the presented method utilizes milder conditions, as well as shorter reaction times. Both samples of g-h-PCN directly after milling and aging and after an hour of annealing at 300 °C (g-h

• broad Bragg reflections at 2θ = 16° and 28°. This suggests a high thermal stability of the g-h-PCN structure, being formed during the mild milling and aging conditions, with no need for annealing. X-ray photoelectron spectroscopy (XPS) To gain insight into the atomic speciation within the structure and

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

• Supporting Information File 1. Both compounds were further purified by temperature-gradient vacuum sublimation and characterized by 1H and 13C NMR spectroscopy (Figures S9–S12, Supporting Information File 1) as well as high-resolution mass spectrometry. Photophysical studies and DFT calculations The UV–vis

• emitters in toluene are summarized in Table 1. Time-resolved spectroscopy Further, the fluorescence lifetimes on the nanosecond and microsecond timescales of both emitters were recorded in degassed THF to understand the photon upconversion process (Figure 2 and Tables S6 and S7 in Supporting Information

• quenching and recovery were obtained for both compounds upon addition of acid and base. Thereby, the protonation–deprotonation events were confirmed using absorption spectroscopy (Figure S6, Supporting Information File 1). The new peak at λabs = 425 nm in the absorption spectrum of BPy-pTC upon adding TFA

Synthesis of N-phenyl- and N-thiazolyl-1H-indazoles by copper-catalyzed intramolecular N-arylation of ortho-chlorinated arylhydrazones

• Yara Cristina Marchioro Barbosa,
• Guilherme Caneppele Paveglio,
• Claudio Martin Pereira de Pereira,
• Sidnei Moura,
• Cristiane Storck Schwalm,
• Gleison Antonio Casagrande and
• Lucas Pizzuti

Beilstein J. Org. Chem. 2022, 18, 1079–1087, doi:10.3762/bjoc.18.110

• . All products were fully characterized by HRMS as well as 1H and 13C NMR spectroscopy. Thus, this approach is valuable for promoting the synthesis of N-phenyl-1H-indazoles in a higher yield than that reported in the literature using copper catalysis and the same substrates. This study also prompted the

• of CuI, only the product 2i’ or 4i’, respectively, was detected by 1H NMR spectroscopy in the crude reaction mixture (Figures S7–S10 and Figures S11–S14, respectively, Supporting Information File 1). This result shows that o-fluorinated arylhydrazones may be suitable as starting materials to prepare

• determination of the amount of product and/or starting material in the crude mixture by 1H NMR spectroscopy was conducted by adding 1 equiv of trichloroethylene as calibration compound after diluting the crude mixture in CDCl3. The amounts were estimated by comparing the integral value of the product C3–H

Facile and diastereoselective arylation of the privileged 1,4-dihydroisoquinolin-3(2H)-one scaffold

• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1070–1078, doi:10.3762/bjoc.18.109

• substituent and an N-alkyl group (considering that N-aryl nitrophenyl-substituted compound 10o was obtained in a respectable 91% yield). The structures of compounds 10a–s were unequivocally confirmed by 1H and 13C NMR spectroscopy (paying a particular attention to the appearance of the C=N2 signal in the

• ). Using more reactive (electron-rich) arenes results in lower diastereoselectivity and regiospecificity of the reaction (cf. 9q, 9v, and 9w). The structure and the initially anticipated trans-configuration of the products 9 was unequivocally confirmed by 1H and 13C NMR spectroscopy as well as, in the case

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• stannyl D–π unit with 1,3-diiodobenzene, respectively. Their optical and electrochemical properties were investigated by photoabsorption and fluorescence spectroscopy, time-resolved fluorescence spectroscopy, cyclic voltammetry (CV) and molecular orbital (MO) calculations. In toluene the photoabsorption

• properties (Φfl-solid = 0.24 nm), compared with OTK-2 (Φfl-solid = 0.15 nm). CV results demonstrated that OTT-2 and OTK-2 exhibit a reversible oxidation wave. Based on photoabsorption, fluorescence spectroscopy and CV for the two dyes, it was found that the lowest unoccupied molecular orbital (LUMO) energy

• –π)2Ph-type fluorescent dyes. Herein, we report the syntheses of (D–π)2-type and (D–π)2Ph-type fluorescent dyes and their optical and electrochemical properties based on photoabsorption and fluorescence spectroscopy, time-resolved fluorescence spectroscopy, cyclic voltammetry (CV) and molecular

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

• Dharmendra Das,
• Akhil A. Bhosle,
• Amrita Chatterjee and
• Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

• acknowledge the Central Instrumentation Facilities of BITS-Pilani, Pilani campus and K. K. Birla Goa campus, and Central Analytical Laboratory of BITS-Pilani, Hyderabad campus for NMR spectroscopy.

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 991–998, doi:10.3762/bjoc.18.99

• clearly indicated that only one diastereoisomer was actually produced in the reaction. The chemical structures of the compounds 4a–k were established by various spectroscopy methods. Additionally, the single crystal structures of compounds 4a and 4c were successfully determined (Figure 2 and Figure 3

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• which oxalyl chloride was added at room temperature, and then reacted with aluminium trichloride at 0 °C. The resulting material was not soluble in cold dichloromethane/chloroform, but was found to be sufficiently soluble in hot chlorinated solvents. NMR spectroscopy in deuterated DMSO indicated that

• refluxed overnight [43]. The result was a dark violet/black material, which was not soluble in common organic solvents, thereby preventing NMR spectroscopy. Also, sublimation failed. However, the mass could be measured with MALDI mass spectrometry, and microanalysis results matched the theoretical values

• assumed that the reactive 5-position of thiophene underwent further reactions under the aggressive Friedel–Crafts acylation conditions [53]. Physical properties Absorption spectroscopy The target material EtH-T-DI-DTT (1) is a dark solid and forms dark violet solutions at low concentrations. Solution

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• the reaction. Unless stated otherwise, a purity of at least 95% was obtained for all the compounds by means of chromatography or recrystallization and this level of purity was established by TLC, LC–MS, and NMR spectroscopy. General protocol for the experiments described in Table 1, description of