Trichloroacetic acid fueled practical amine purifications

• Aleena Thomas,
• Baptiste Gasch,
• Enzo Olivieri and
• Adrien Quintard

Beilstein J. Org. Chem. 2022, 18, 225–231, doi:10.3762/bjoc.18.26

• their protonated salt formation, enabling the separation with the impurities. From these amine salts, simple decarboxylation of TCA liberates volatile CO2 and chloroform affording directly the pure amines. Through this approach, a broad range of diversely substituted amines could be isolated with

• since the beginning of the 19th century as highlighted by the Sertürner isolation of morphine [4]. However, after formation of the amine acid (ammonium) salt and separation of the impurities, another separation is required to liberate again the free amine resulting in the undesired generation of waste

• . Most notably, this step can go through a liquid–liquid separation that requires multiple operations generating large amounts of waste notably arising from the different organic and aqueous layers. In the context of the development of more eco-compatible organic synthesis limiting the number of

Diametric calix[6]arene-based phosphine gold(I) cavitands

• Gabriele Giovanardi,
• Andrea Secchi,
• Arturo Arduini and
• Gianpiero Cera

Beilstein J. Org. Chem. 2022, 18, 190–196, doi:10.3762/bjoc.18.21

• via conventional protocols using (Me2S)AuCl. Notably, the organometallic macrocycles A,B,C(AuCl)2 could be isolated via column chromatography separation. Gold(I) catalysts were subsequently fully characterized by NMR analysis and high-resolution mass spectrometry. The conformation of the catalysts, in

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

• Soumyadip Basu,
• Sauvik Chatterjee,
• Suman Ray,
• Suvendu Maity,
• Prasanta Ghosh,
• Asim Bhaumik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 133–142, doi:10.3762/bjoc.18.14

• towards heterogenization of the catalytic systems used in the field of environmental chemistry keep growing day by day. These allow complete separation of novel or harmful catalysts from the mixture and reuse for further treatment. This makes the whole catalytic processes more efficient and cost-effective

• . In contrast, our work unites various aspects of green chemistry, such as a minimal reaction time, a high conversion rate, a green solvent, environmentally friendly reaction conditions, and an effortless separation and recyclability of the catalyst. Altogether, the detailed summary in Table 3

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• reactive complexes of ruthenium and the high reusability and easy separation procedures of heterogeneous catalysts have proven the fact that this metal serve as highly effective catalyst for a wide range of organic transformations. It will surely motivate the scientific community to develop more

Stepwise PEG synthesis featuring deprotection and coupling in one pot

• Logan Mikesell,
• Dhananjani N. A. M. Eriyagama,
• Yipeng Yin,
• Bao-Yuan Lu and
• Shiyue Fang

Beilstein J. Org. Chem. 2021, 17, 2976–2982, doi:10.3762/bjoc.17.207

• using the expensive catalyst that was used in the literature [32] due to cost considerations. Another method we tried was to react excess TsO(PEG)4OTs with 2-phenylethan-1-ol under basic conditions to give 2 (Scheme 3). However, separation of 2 from TsO(PEG)4OTs and Ph(CH2)2O(PEG)4O(CH2)2Ph required

Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

• Tanmoy Halder and
• Somnath Yadav

Beilstein J. Org. Chem. 2021, 17, 2915–2921, doi:10.3762/bjoc.17.199

• step synthesis, though the former involved two extra steps for the synthesis of the first glycosidic donor and one chromatographic separation. The synthesis of the desired product was achieved through manipulations of the appropriate protecting group on the monosaccharides and subsequent realization of

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• separation of the HOMO and LUMO on donor and acceptor, respectively, will result in an S1→S0 transition with predominantly charge transfer (CT) character. Highly twisted donor–acceptor architectures are typically employed to realize small ΔEST [4][8]. SOC can be enhanced by ensuring that the nature of the S1

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

• Chuanhua Qu,
• Run Huang,
• Yong Li,
• Tong Liu,
• Yuan Chen and
• Guiting Song

Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193

•  6). The reaction of 1a with TosMIC derivative 2c, bearing an aromatic ring smoothly occurred to provide product 3a; more importantly, the presence of p-chlorobenzaldehyde (I) released from 2c can be detected by separation and 1H NMR analysis (Scheme 6A). This result indicates that TosMIC may

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• causing of the selective formation of the cis- versus the trans-aggregate observed after X-ray diffraction analysis, but calculations did not give any clear interaction to confirm it. The polar solvent methanol used for the reaction and separation could favor this chemical arrangement. Ligands L1 and L3

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• -catalyzed enantioselective transformations [9][14][22][23]. Axial chirality is also found in chiral stationary phases for enantioselective separation, dopants in liquid-crystalline materials, chiroptical molecular switches, microporous soluble polymers, and interlocked nanotubes (Figure 3) [24]. In addition

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• enantiomerically pure alkaloids, as numerous methods for separation of enantiomers are well known in this field [52][53][54][55]. Further, this protocol might be extended to an asymmetric N-acyl-Pictet–Spengler condensation by using homochiral carbamates, as demonstrated by Comins [18], or by using

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• -oxathiolane ring with different nucleobases in a way that only one isomer is produced in a stereoselective manner via N-glycosylation. An emphasis has been placed on the C–N-glycosidic bond constructed during the formation of the nucleoside analogue. The third focus is on the separation of enantiomers of 1,3

• ; separation of racemic nucleosides; stereoselectivity; Introduction Among all the biomolecules in an organism, nucleic acids, namely DNA and RNA, have the unique role of storing the genetic code – the nucleotide sequence that specifies the amino acid sequence of proteins that is essential for life on Earth

• , ii) a stereoselective N-glycosylation process that is compatible with an enantiomerically pure substrate, and iii) separation of enantiomers by chemical or enzymatic resolution methods. This review summarizes the methods used to synthesize 1,3-oxathiolane nucleosides. Many methods provide the

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• which the key intermediate, pyrrolidine derivative 2, can be obtained in three steps according to the literature procedure [32]. Using this method, we obtained the product 2 in a yield comparable (56% overall yield) to that described in the literature. However, the difficult chromatographic separation

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• used to shift a four-carbon chain one position on the bicyclic molecule 32 using the base calcium methoxide with a yield of 70% of 33 and a diastereomeric ratio of 3:1 (14:1 after separation) (Figure 8) [11]. Note that 33 bears an enone moiety, and therefore, this reaction is apparently the first

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

• material could be a potential for targeting release in the colon. 4. Other cryogel applications For cryogel biomedical applications not discussed in section 5, including cell separation, tissue engineering scaffolds, bioreactors and capturing of target molecules, the reader is directed to a recent review

• by Bakhshpour et al. [54]. In addition to the biomedical applications discussed in detail below, cryogels have a variety of potential uses in fields such as tissue engineering [12], chromatography, and separation applications. For example, for the filtration of biologically relevant molecules [19][42

Synthesis of 5-arylacetylenyl-1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions

• Andrey I. Puzanov,
• Dmitry S. Ryabukhin,
• Anna S. Zalivatskaya,
• Dmitriy N. Zakusilo,
• Darya S. Mikson,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2021, 17, 2417–2424, doi:10.3762/bjoc.17.158

• Information File 1). It should be noted that attempts of chromatographic separation of triflates 4a–c into individual E- and Z-isomers on silica gel led to a decrease of their yields and a change in E/Z-ratio. That reveals instability of these compounds on silica gel. In the same reaction in H2SO4 (Scheme 4

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B

• Emmanuel T. Oluwabusola,
• Olusoji O. Adebisi,
• Fernando Reyes,
• Kojo S. Acquah,
• Mercedes De La Cruz,
• Larry L. Mweetwa,
• Joy E. Rajakulendran,
• Digby F. Warner,
• Deng Hai,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156

• crude extract. The extract (8.2 g) was dissolved in H2O and CH2Cl2 (700 mL, 50% v/v) and placed in a separating funnel for 5 min to allow for proper separation of the constituent mixture between the aqueous (6.21 g) and organic phases (1.99 g) [46]. The dichloromethane fraction (1.99 g) was

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• -containing mixture of diastereomeric alicyclic derivatives 59. The tetrahydropyrimidin-4(1H)-one-mercuri trifluoroacetate derivative 59 on successive treatment with NaBr and LiBH4 gives a mixture of tetrahydropyrimidin-4(1H)-one derivatives 60 in the diastereomeric ratio of 63:37 after separation by column

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• fractions. The MeOH fraction was subjected to separation on a silica gel column (CHCl3/MeOH/H2O 6:1:0.1 → 1:1:0.1) to afford five fractions (BM1–BM5). Fraction BM3 (2.5 g) was fractionated over an RP-C18 silica gel column, eluting with gradient solvent system (25 → 100% aq. MeOH) to give nine subfractions

A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids

• Li Liu,
• Yue Li,
• Tiao Huang,
• Dulin Kong and
• Mingshu Wu

Beilstein J. Org. Chem. 2021, 17, 2321–2328, doi:10.3762/bjoc.17.150

• chromatography separation is not usually required. This outcome indicated that the transformation could be applicable for larger-scale syntheses of 3-monohalooxindoles products. In addition, the structure of all products 3 and 4 was unambiguously assigned by 1H and 13C NMR spectroscopy and HRMS. Especially the

Synthesis of O⁶-alkylated preQ₁ derivatives

• Laurin Flemmich,
• Sarah Moreno and
• Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

• vigorously for one and a half hour until satisfactory phase separation was achieved. The aqueous layer was separated and subsequently extracted three times with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate and evaporated. The residue was purified by flash

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• thermoresponsive behavior of polymers is governed by oriented polymer–polymer interactions, such as hydrogen bonding or electrostatic interactions. As a function of temperature, these attractive interactions are formed and contribute to phase separation (T < UCST) or are increasingly destabilized and allow

• separation with an LCST or UCST and its dependence on brush parameters, such as local concentration, and thus on its influenceability. It has often been shown experimentally that the most pronounced conformational response of polymer brushes is achieved at moderate grafting densities [125]. Furthermore, the

• the chains on a surface and the intermolecular interaction that occurs, vertical phase separation is suppressed in systems such as polystyrene in cyclohexane, in contrast to free dissolved chains [128]. However, at vanishingly small concentrations, classical brushes always exhibit a behavior

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

• Zsanett Benke,
• Attila M. Remete and
• Loránd Kiss

Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132

• (7g, Scheme 11). However, dimetathesized product (±)-18c was not formed, and isolation of monometathesized products (±)-18a and (±)-18b (or a mixture thereof) in pure form failed despite repeated attempts of chromatographic separation. Finally, isoxazoline (±)-5 was subjected to CM with 4

• attempts of chromatographic separation. Finally, CM reactions between isoxazoline (±)-6 and 4-fluorostyrene (7h) were studied (Scheme 18 and Table 16). HG-2 catalyst provided monocoupled (±)-25a and dicoupled (±)-25c in a comparable amount. With G-2 catalyst, both products were formed in higher yield. G-3

• regioselectivity in all successful CM reactions. The ratio of monometathesized products in CM reactions of (±)-4 and (±)-5 also depended on the catalyst. Generally, HG-2 catalyst provided the highest regioselectivity. Unfortunately, separation of regioisomeric monometathesized compounds proved to be impossible in

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

• Ryan M. Alam and
• John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

• from the N-2 position to the N-1 atom by the indazole C-3 substituent (vide infra). While the corresponding N-1 and N-2 regioisomers arising from the N-alkylation of C-3 substituted indazoles 12–24 were generally amenable to separation using wet flash column chromatography, the corresponding N-1- and N

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• to create an epimeric mixture of the dinucleotide phosphoramidate-linked derivatives with subsequent separation of the two stereoisomers. These were then incorporated into the desired ONs after O3’-desilylation and phosphitylation of the dimers [107]. The authors found that for each of the sequences