Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides

• Petar Štrbac and
• Davor Margetić

Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75

• established by 1H NMR analysis and comparison with product 10. The most indicative signals are of N-methyl groups, which are at an almost identical position for the bent isomer 38 (2.36 ppm), as in products 10 and 33 (2.38 and 2.37 ppm, respectively). The chemical shift of the NMe group in linear product 36

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• fermentation of E. coli/pET28-297 was performed. After induction of protein expression, the precursor 8-HQA and farnesol were added to the culture and incubated overnight. MS-guided purification of cell lysate and 1H NMR analysis of the prenylated 8-HQA product confirmed the prenylation on the quinoline ring

Rapid gas–liquid reaction in flow. Continuous synthesis and production of cyclohexene oxide

• Kyoko Mandai,
• Tetsuya Yamamoto,
• Hiroki Mandai and
• Aiichiro Nagaki

Beilstein J. Org. Chem. 2022, 18, 660–668, doi:10.3762/bjoc.18.67

• pressure regulator (BPR). The reaction solution was cooled to ambient temperature in a water bath at the position right before BPR and collected in a sample vial. The solution was then immediately diluted with deuterated chloroform for 1H NMR analysis. Investigation of the temperature effect Initially, we

• against the operation time as shown in Figure 5. As demonstrated clearly, the production of cyclohexene oxide was maintained constant and high during 1-hour operation. As a result, the productivity was integrated to reach 3.7 g/h reliably, determined by 1H NMR analysis. Investigation of the equivalents of

• condenser. The reaction temperature was controlled either in a water bath or an oil bath. At a certain reaction time, 50 μL of the reaction solution was taken out using a gastight syringe and immediately diluted with deuterated chloroform for 1H NMR analysis. General procedure for epoxidation of cyclohexene

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• yields (Table 1, entries 2–5). In the case of N-benzyl-substituted DAS, byproduct azine 4 was detected by NMR analysis (Table 1, entry 6). The formation of these byproducts was also observed in the case of other DAS bearing alkyl groups at the nitrogen atom (Table 1, entries 10–13) as well as in the case

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• cavitand hosts were also modified with imidazolium cationic or carboxylic anionic feet [29]. Before the reaction, NMR analysis of the host–guest complex indicated that the bound guest was in yo-yo motions time-averaged between unsymmetrical J-shaped conformations and symmetrical U-shaped ones. Treatment of

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• optimized conditions (Table 1, entry 12) followed by flash chromatography, the unprecedented bisoxindole 2a was fully characterized by high-resolution mass spectrometry and by one- and two-dimensional NMR analysis. In particular, from HSQC, HMBC and COSY experiments all single frequencies could be safely

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• and purity (qualitative assessment based on the NMR analysis) without further purification. Enzyme inhibition assays The inhibitory activities of compounds 3a–h toward TcTS and neuraminidase were assessed by a continuous fluorimetric assay [34], which is based on the residual hydrolase activity 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

• conformers, in slow exchange on the NMR timescale, was finally confirmed by variable temperature NMR analysis performed for A(AuCl)2 using tetrachloroethane-d2 as the solvent (Figure 3). Catalytic studies To probe the role of the cavity and the influence of the position of the gold(I) nuclei implanted on the

• scavenger [37]. After 4 h, NMR analysis of the crude reaction mixture revealed high conversion of the starting material with the formation of the 6-endo-dig rearranged diene 2a and the parental regioisomer 2b in a 1:1 ratio. Noteworthy, this latter is formed by an initial 5-exo-dig cyclization step (entry 1

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• ). To mitigate this, the milling experiment was repeated using silica gel (SiO2) as a milling auxiliary. The use of SiO2 did not affect significantly the product composition of the reaction as determined by NMR analysis of an independent experiment milling 1c and NFSI (2.0 equiv) at 30 Hz for 3 h. This

• fluorination of arenes 1 with NFSI. (a) Product distributions and reaction conditions: Arenes 1 (0.148 mmol) were milled with NFSI (1.0–2.0 equiv) in a 2 mL Eppendorf tube with four ZrO2 milling balls (350 mg in total mass) at 25–30 Hz for 3 h. The yield of the products was determined by NMR analysis with 4

• %; (SO2Ph)2NCH3 yield = 82%. (b) Powder X-ray diffraction (PXRD) patterns measured for the reactants and simulated PXRD patterns for the published (SO2Ph)2NCH3 (CCDC ZAJBIZ) and (SO2Ph)2NH (CCDC BSULFA). (c) 1H NMR analysis of the reaction mixture of the milling of 1c and NFSI (2.0 equiv) at 30 Hz for 3 h

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

• Takayoshi Kasakado,
• Takahide Fukuyama,
• Tomohiro Nakagawa,
• Shinji Taguchi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2022, 18, 152–158, doi:10.3762/bjoc.18.16

• °C, temperature change rate of 5 °C/min to 250 °C, hold at this temperature for 10 min. Yields were determined by using the percentage peak area method with compensation for the relative sensitivities of each component. Product 2 and byproduct 2’ were confirmed by 1H and 13C NMR analysis (see

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• . The methylene carbon C35 adjacent to the hydroxamic acid group showed a smaller chemical shift (δC 28.0). The positional assignment of C34 and C35 was made by a ROESY correlation observed between H34 and 32-NH (Figure 2). To verify the structure deduced from the NMR analysis, an MS/MS analysis was

Regioselective synthesis of methyl 5-(N-Boc-cycloaminyl)-1,2-oxazole-4-carboxylates as new amino acid-like building blocks

• Jolita Bruzgulienė,
• Greta Račkauskienė,
• Aurimas Bieliauskas,
• Vaida Milišiūnaitė,
• Miglė Dagilienė,
• Gita Matulevičiūtė,
• Vytas Martynaitis,
• Sonata Krikštolaitytė,
• Frank A. Sløk and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2022, 18, 102–109, doi:10.3762/bjoc.18.11

• the corresponding reaction mixtures, they were identified using LC–MS analysis, and were immediately treated with hydroxylamine hydrochloride in an appropriate solvent to obtain the target 1,2-oxazoles 4a–h. A representative β-enamino ketoester 3a was subjected to a detailed NMR analysis (Figure 2a

The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• of Scheme 2. The site of incorporation for the deuterium uptake was evident from incubations of (3-13C)FPP and (12-13C)FPP [25] in deuterium oxide (Scheme 5B and 5C). The 13C NMR analysis of the obtained products showed slightly upfield-shifted triplets for C3 (Δδ = −0.45 ppm, J = 19.4 Hz) and C12

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• , copies of 1H and 13C spectra and additional information of antiproliferative assay. Acknowledgements The authors acknowledge the assistance of Mrs. Izabel C. C. Turatti, Mr. José C. Tomaz and Mr. Vinicius Palaretti in the GC–MS, HRMS and NMR analysis, respectively. Funding The authors gratefully thank

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• structure for the HAT reaction between the DABCO radical cation and isovaleraldehyde obtained at the DFT/M06-2X/cc-pVTZ level. Bond lengths and angle are presented. Aryl bromide and aldehyde scope. Isolated yields. aYield determined by 1H NMR analysis with 1,3-benzodioxole as internal standard. bAlso

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• . Unfortunately, no products other than the formyl compound were isolated after photocleavage of compound 1 or 6 in acidic conditions. Instead, when irradiation of alkenyl amide 1 was conducted in acetone, crude NMR analysis indicated the appearance of product 8 as well as new peaks in the aromatic region

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

Ligand-dependent stereoselective Suzuki–Miyaura cross-coupling reactions of β-enamido triflates

• Tomáš Chvojka,
• Athanasios Markos,
• Svatava Voltrová,
• Radek Pohl and
• Petr Beier

Beilstein J. Org. Chem. 2021, 17, 2657–2662, doi:10.3762/bjoc.17.179

• 2D ROESY NMR analysis showing interaction between the alkenyl hydrogen and ortho-hydrogens on the aryl rings. Based on previously proposed mechanisms of isomerization in Suzuki cross-coupling reactions, we suggest the following explanation for the observed isomerization [25][29] (Scheme 3). In the

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

• Akhil K. Dubey and
• Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

• conditions: 1 (0.2 mmol), 2 (0.5 mmol), catalyst VII (0.01 mmol, 5 mol %) at 30 °C. aIsolated yield of 3 after column chromatography. bConversion in % of the starting material 1 is given in parentheses, determined by 1H NMR analysis of the crude reaction mixture. cDetermined by HPLC using a chiral stationary

• equiv) was used. Synthesis of ent-3. Reaction conditions: 1 (0.2 mmol), 2 (0.5 mmol), catalyst VIII (0.01 mmol, 5 mol %) at 30 °C. aIsolated yield of ent-3 after column chromatography. bConversion in % of the starting material 1 is given in the parentheses, determined by 1H NMR analysis of the crude

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• tetrazole formation. In support of this was the fact that no lactam byproduct was detected in reactions carried out with TMSN3. As it was confirmed by detailed NMR analysis (see Supporting Information File 1), only homoregioisomeric 12a-azatetrazoles were obtained. This is in good correlation with earlier

• to be less reactive in comparison to the 12-oxo counterparts, which can be attributed to the fact that the migrating carbon atom (C-8) is less substituted than the C-13 carbon atom. Structures of all compounds were determined by a detailed NMR analysis. For B-homotetrazoles 17 and 18, a retention of

• , TMSOTf proved to be the most efficient. High yields of the desired tetrazole compounds with no lactam byproduct were obtained. The molecular structure and stereochemistry of newly synthesized tetrazoles was established by detailed NMR analysis. For compounds 13 and 14, the structure was established by

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• at 4.42 ppm and appearance of the new signal at 8.67 ppm corresponding to the triazole moiety confirmed successful click reaction under white LED exposure conditions after 4 h (Figure 3a). Kinetic studies conducted by 1H NMR analysis confirmed that the click reaction between benzyl azide and

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

• in the isolation and characterization of 14 lignan derivatives including three new neolignan glycosides (1–3), four phenolic glycosides including a new compound (15), and a new cyanoglycoside (16) from the organic extracts. The structures of the new compounds were established by NMR analysis (1H and

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

• catalyst-dependent (Table 1). In the presence of HG-2, the main product was dicoupled (±)-8c accompanied by the unseparable mixture of monocoupled products (±)-8a and (±)-8b. Despite the partial signal overlap, 2D NMR analysis of the (±)-8a and (±)-8b mixture was possible, and the structure of both (±)-8a

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• ][260]. The automated solid-phase approach required only two BBs with the amino group protected either with the N-TCA 79 or with the N-Cbz group 80 (Scheme 12). Compounds 81–85 served as standards to explore the conformational space of COS with different PA. NMR analysis and MD simulations revealed the

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

• ) HMBC NMR analysis and confirmatory regiochemical assignment. Similarly, while the regioisomeric products arising from the N-alkylation of indazole 21 could not be separated using wet flash column chromatography or PTLC, a significantly enriched sample of the corresponding N-1 regioisomer (ratio N-1 (43