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

• the chlorination of compound 1. Acknowledgements We thank Prof. Masaaki Sato and Dr. Hitoshi Mitsui at MiChS Inc. for useful discussions. IR thanks the Center for Emergent Functional Matter Science at NYCU for support.

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

• genus Tenacibaculum. Experimental General experimental procedures UV and IR spectra were measured on a Shimadzu UV-1800 spectrophotometer and a PerkinElmer Spectrum 100 spectrophotometer, respectively. NMR spectra were recorded on a Bruker AVANCE NEO 500 spectrometer using the signals of the residual

• ): pale brown powder; UV (MeOH) λmax nm (log ε): 201 (4.82) nm; IR (ATR) νmax: 3305, 2916, 2849, 1613, 1538, 1466 cm−1; 1H and 13C NMR, Table 1; HR–ESITOFMS (m/z): [M − H]− calcd for C33H60N5O8, 654.4447; found, 654.4449; [M + Na]+ calcd for C33H61N5O8Na, 678.4412; found, 678.4412. Tenacibactin L (2

• ): pale brown powder; UV (MeOH) λmax nm (log ε): 202 (4.21) nm; IR (ATR) νmax: 3306, 2916, 2849, 1613, 1538, 1466 cm−1; 1H and 13C NMR, Table 2; HR–ESITOFMS (m/z): [M − H]− calcd for C33H60N5O8, 654.4447; found, 654.4445; [M + Na]+ calcd for C33H61N5O8Na, 678.4412; found, 678.4410. Tenacibactin M (3

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

• structural assignment of regiospecific compound 4a was readily deduced via detailed spectral data analysis. The IR spectrum of 4a contained characteristic absorption bands such as 1723 (C=O, ester), and 1687 (C=O, Boc) cm−1. The 1H NMR spectrum of compound 4a revealed a characteristic resonance for the Boc

Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

• Sandeep Kumar,
• Jyotirmoy Maity,
• Banty Kumar,
• Sumit Kumar and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

• configuration of that chiral centre as (R) in the 2′-O,5′-C-bridged-β-ᴅ-homoarabinofuranosyl-nucleosides 9a,b. The structures of all the synthesized compounds 9a,b, 11, 12a,b, 13a,b, 14a,b, 15a,b, 16a,b, 17, 18, 19, 20a,b, 21a,b, and 22a,b were unambiguously established on the basis of their spectral (IR, 1H

Efficient synthesis of ethyl 2-(oxazolin-2-yl)alkanoates via ethoxycarbonylketene-induced electrophilic ring expansion of aziridines

• Yelong Lei and
• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6

• , and the chemical shifts (δ) are reported in parts per million (ppm). All coupling constants (J) in 1H NMR are absolute values given in hertz (Hz) with peaks labeled as singlet (s), broad singlet (brs), doublet (d), triplet (t), quartet (q), and multiplet (m). IR spectra (KBr pellets, v [cm−1]) were

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

• -bromobenzonitrile (2) under different amounts of DABCO. Two inorganic bases were tested: potassium carbonate (K2CO3) and sodium hydrogen carbonate (NaHCO3). Reactions in the absence of inorganic bases were also performed (Table 1). An excited iridium photocatalyst (Ir[dF(CF3)ppy]2(dtbbpy)PF6) was used for the one

• strongly oxidizing complex *Ir[dF(CF3)ppy]2(dtbbpy) (PC*) (E1/2red [*IrIII/IrII] = +1.21 V vs SCE in CH3CN). The *Ir(III) excited state is quenched by DABCO (E1/2ox = +0.69 V vs SCE) producing DABCO radical cation and the reduced Ir(II) complex. Subsequently, DABCO radical cation engage in a HAT event with

• performed in the absence of DABCO (see Supporting Information File 1, Scheme S2 for details). cAldehyde (10 equiv), performed at 40 °C without cooling fan. dAldehyde (10 equiv). Mechanistic investigations of the HAT reaction using DABCO. Proposed mechanism for aldehyde arylation. PC = photocatalyst Ir[dF

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• determined to be C10H16O2 on the basis of its NMR and HR–ESI–TOFMS data (m/z 191.1044 [M + Na]+, Δ + 0.1 mmu). Three degrees of unsaturation, calculated from the molecular formula, a UV absorption maximum at 264 nm, and IR absorption bands at 1679 and 2800–3200 cm−1, suggested dienone and hydroxy

• molecular formula was determined to be C18H22N2O3 based on its NMR and HR–ESI–TOFMS data (m/z 313.1556 [M – H]–, Δ – 0.2 mmu), corresponding to nine degrees of unsaturation. The UV spectrum, exhibiting the absorption maxima at 229 and 282 nm, was typical of an indole functionality. The IR absorption bands

• spectrophotometer. IR spectra were measured on a PerkinElmer Spectrum 100. NMR spectra were obtained on a Bruker AVANCE II 500 or AVANCE NEO 500 spectrometer in DMSO-d6 or CDCl3, and referenced to the residual solvent signals (δH 2.50, δC 39.5 for DMSO-d6; δH 7.26, δC 77.2 for CDCl3). HR–ESI–TOFMS spectra were

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

• DICzTRZ were determined by a combination of NMR spectroscopy, mass spectrometry, and IR spectroscopy. Theoretical calculations Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations in the gas phase at the PBE0/6-31G(d,p) level reveal the potential of DICzTRZ as a TADF material. The

• orientation behaviour. It was shown, for example that phosphorescent iridium complexes like Ir(ppy)2(acac) display horizontal orientation (a ≅ 0.25) after vacuum co-evaporation, while the orientation changed toward isotropic in spin-coated films with PMMA as the host [39]. Moreover, upon solution processing

Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol

• Lin Zhang,
• Jun Zheng,
• Guangyan Luo,
• Xiaoyue Li,
• Yunqian Zhang,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194

• (CPE) was investigated using single-crystal X-ray diffraction spectroscopy, isothermal titration calorimetry (ITC) and UV–vis, NMR and IR spectroscopy. The effects of Q[8] on the stability, in vitro release performance and antibacterial activity of CPE were also studied. The results showed that CPE and

• consistent with our single-crystal X-ray analysis of CPE@Q[8] shown in Figure 2. IR spectroscopy Figure 6 shows the IR spectra recorded for Q[8] (a), CPE (b), a physical mixture of Q[8] and CPE {n(Q[8])/n(CPE) = 1:1} (c) and the CPE@Q[8] inclusion complex (d). By comparison, spectrum (c) is a simple

• . Conclusion Herein, the 1:1 host–guest complex of CPE and Q[8] was confirmed using single-crystal X-ray diffraction and 1H NMR, UV–vis and IR spectroscopy. The CPE molecule completely enters the cavity of Q[8] with an inclusion constant of 5.474 × 105 L/mol. The intervention of Q[8] has no effect on the

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

• the IR spectra (recorded using a Nicolet 510 P-FT) are listed and wave numbers are given in cm−1. Nuclear magnetic resonance spectra and decoupling experiments were determined at 250 MHz on a Q.E 300 instrument, at 300 MHz on a Bruker Avance AC-300 and at 500 MHz on a Bruker AM500 spectrometer as

• ), 129.4 (2C), 129,2 (4C), 128.8 (2C), 128.2 (4C), 127.7 (2C), 127.5 (2C), 73.1 (2C), 63.1 (2C), 52.9 (2C), 51.5 (2C), 45.5 (2C), 40.2 (2C), 36.4 (2C); IR (cm−1) νmax: 3027, 2948, 1738, 1587, 1492, 1398, 1359, 1244, 1101, 1023, 704; ESIMS m/z: 1234 (21), 1233 (30), 1232 (47), 1231 (M+, 64), 1230 (100

• ), 72.8 (2C), 60.6 (2C), 55.8 (2C), 55.1 (2C), 52.7 (2C), 51.5 (2C), 45.8 (2C), 40.4 (2C), 36.8 (2C); IR (cm−1) νmax: 3023, 2947, 1735, 1587, 1496, 1396, 1361, 1268, 1205, 1122, 1024, 703; ESIMS m/z: 1216 (5), 1215 (25), 1214 (M+, 38), 1213 (67), 1212 (100); anal. calcd for C62H66N4NiO14S2: C, 61.3; H

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• −5 M). Photooxidation rate constants and singlet oxygen quantum yield of compounds 3aa–fa and 3bb–be in DMSO solution. Supporting Information Supporting Information File 270: NMR spectra of the compounds, IR spectra, crystallographic data, photophysical and singlet oxygen spectra of new structures

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

• Alla I. Vaskevych,
• Nataliia O. Savinchuk,
• Ruslan I. Vaskevych,
• Eduard B. Rusanov,
• Oleksandr O. Grygorenko and
• Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

• [13], as well as Ir-catalyzed intramolecular dehydrative cross-coupling of 2-(pyrrolidine-1-yl)benzamide [14]. Another approach to compounds of type 1 that relies on a cascade formation of the pyrimidine and pyrrole rings have found much wider application (see Scheme 1B). One of its variations

• alkaloids – that can be used as building blocks to obtain natural product-like compound libraries of potential biologically active compounds. Experimental Commercially available reagents and solvents were used without further purification. The IR spectra of the compounds obtained were recorded on a Bruker

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

• Finnigan LTQ FT Ultra Fourier Transform Ion Cyclotron Resonance device at 250 °C for ESI. IR spectra were recorded on a Perkin Elmer FT-IR Paragon 1000 instrument as neat materials. Absorption bands were reported in wave numbers (cm−1), obtained on a ATR PRO450-S accessory (Jasco). Melting points were

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

• solution of NaHCO3 (3 × 40 mL), dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (eluent, hexane/ethyl actate 7:1→5:1), affording the product as dark orange oil in 86% yield. Rf 0.5 (hexane/EtOAc 3:1); IR (ATR): 2971, 2089, 1390

• (300 MHz, CDCl3) δ 9.17 (s, 1H), 6.85 (s, 1H), 4.17–4.09 (m, 1H), 3.83–3.72 (m, 1H), 3.44–3.32 (m, 3H), 2.10–2.00 (m, 1H), 1.97–1.82 (m, 2H), 1.77–1.64 (m, 1H), 1.49 (s, 9H), 1.31 (s, 9H); 13C NMR (75 MHz, CDCl3) δ 181.9, 157.2, 80.8, 57.6, 55.8, 53.3,47.3, 29.5, 28.5, 23.9, 22.1 ppm; IR (ATR): 3270

• (s, 1H), 6.96 (s, 1H), 4.17–4.09 (m, 1H), 3.76–3.67 (m, 1H), 3.49–3.38 (m, 2H), 3.36–3.31 (m, 1H), 2.13–2.04 (m, 1H), 1.97–1.81 (m, 2H), 1.78–1.69 (m, 1H), 1.46 (s, 9H), 1.30 (s, 9H) ppm; 13C NMR (151 MHz, CDCl3) δ 182.3, 157.3, 80.6, 57.4, 55.9, 53.7, 47.5, 29.9, 28.5, 24.0, 22.2 ppm; IR (ATR): 3307

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• ]. For example, [Cu(dap)2]Cl (*Cu+/Cu2+ = −1.43 V) provides a stronger reducing power than [Ru(bpy)3]Cl (*Ru2+/Ru3+ = −0.81 V) and [Ir{dF(CF3)ppy}2(dtbbpy)]Cl (*Ir2+/Ir3+ = −0.89 V) [28][30]. Nevertheless, upon absorbing a photon, CuI undergoes a reorganization from a tetrahedral geometry to a square

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• mechanical behavior was studied using rheology. The activation of the supramolecular interactions results in a breaking of these noncovalent bonds, which was investigated using IR spectroscopy, leading to a sufficient increase in mobility and, finally, a healing of the mechanical damage. This scratch-healing

• supramolecular bonds like ionic interactions [27]. In this temperature range, G'' is higher than G' showing that the polymer is uncrosslinked. Thus, the mobility is very high, which is a precondition for the healing. To get further insight into the molecular behavior of P1 and P2, temperature dependent IR

• spectroscopy experiments of drop casted films of the respective polymers were carried out. The respective polymers were heated to 150 °C and an IR spectrum was recorded every 20 K. Afterwards the polymers were air cooled and further spectra at 100, 70, and 25 °C were recorded. Figure 4 displays the aromatic C

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

• , we present a novel synthetic methodology for the photoinduced CuAAC reaction utilizing exfoliated two-dimensional (2D) few-layer black phosphorus nanosheets (BPNs) as photocatalysts under white LED and near-IR (NIR) light irradiation. Upon irradiation, BPNs generated excited electrons and holes on

• azide groups decomposed at higher temperature. The IR spectrum of the cross-linked polymer further demonstrates the formation of a triazole ring by the decrease of the azide peak at 2100 cm−1 (Figure 6b). Representative TEM images recorded at different magnifications of the resulting cross-linked

• the NMR tube. The reaction tube was irradiated by using a Philips 150 W PAR38E E27 halogen pressure glass type bulb with strong IR-A (NIR) emission. The light intensity inside the reaction tube was ≈200 mW·cm−2. The light bulb was attached to the top of a photoreactor setup equipped with a large air

Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4-c]carbazoles via domino Diels–Alder reaction

• Ren-Jie Fang,
• Chen Yan,
• Jing Sun,
• Ying Han and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2021, 17, 2425–2432, doi:10.3762/bjoc.17.159

• chemical structures of the carbazoles were fully characterized by 1H NMR, 13C NMR, IR, and HRMS spectra. To explain the formation of the products, a plausible reaction mechanism was proposed in Scheme 2 on the basis of the previously reported reaction [48][53]. Firstly, the DDQ oxidative dehydrogenation of

• , 125.6, 121.7, 120.7, 120.3, 119.2, 111.3, 21.1; IR (KBr) ν: 2988, 1786, 1734, 1611, 1485, 1456, 1357, 1314, 1185, 1021, 988, 786, 734 cm−1; HRMS–ESI-TOF (m/z): [M + Na]+ calcd for C34H22NaN2O3, 529.1523; found, 529.1512. 2. General procedure for the preparation of carbazoles 6a–n: To a round-bottomed

• , 127.0, 126.9, 126.4, 122.4, 122.0, 121.8, 121.6, 119.6, 108.7, 32.1; IR (KBr) ν: 3057, 3023, 2907, 2360, 2339, 1720, 1605, 1482, 1320, 1267, 1172, 1009, 936, 805, 743, 612, 447 cm−1; HRMS–ESI (m/z): [M + Na]+ calcd for C39H27NO2, 564.1934; found, 564.1926. The crystallographic data of the compounds 3a

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

• hypotheses not previously reported in natural product biosynthesis. Experimental General experimental procedures IR spectra were acquired on a Perkin Elmer Spectrum Two FT-IR spectrometer equipped with an ATR diamond cell. Optical rotations were measured on an ADP 410 digital Polarimeter (Bellingham

• −9.5 (c 0.02, MeOH); UV (MeOH) λmax, nm (log ε): 276 (3.23); IR (cm−1) νmax: 3333, 1677 1660, 1538, 1493, 1203, 1138; NMR data, see Table 1; HRESIMS (m/z): [M − 1]− calcd for C11H13N2O4, 237.0880; found, 237.0874, Δ = −2.53 ppm. Pseudomonin B (2): yellowish oil; [α]D25 −13.3 (c 0.05, MeOH); UV (MeOH

• ) λmax, nm (log ε): 297 (3.64); IR (cm−1) νmax: 3137, 1673, 1660; NMR data, see Table 1; HRESIMS (m/z): [M + H]+ calcd for C16H21O4N4, 333.1557; found 333.1561, Δ = 1.20 ppm. Pseudomonin C (3): white amorphous solid; [α]D25 −45.6 (c 0.02, MeOH); UV (MeOH) λmax, nm (log ε): 299 (3.85); IR (cm−1) νmax

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

• -tetrahydrodehydrodiconiferyl alcohol 4-O-α-ʟ-rhamnopyranoside and was named aleuritiside C. Compound 15 was obtained as a yellow gum. The [M + Na]+ ion peak at m/z 411.1260 (calcd for 411.1267) in the HRESIMS corresponded to the molecular formula C17H24O10. The IR spectrum exhibited signals at 3321 cm−1 and 1675 cm−1

• associated with antineurodegenerative diseases. Experimental General experimental procedures. Optical rotations were measured on a JASCO P-2000 polarimeter. IR spectra were acquired with a JASCO FT/IR-4600 spectrometer. UV spectra were obtained on a Shimadzu UV-1601 UV–visible spectrophotometer. NMR spectra

• semipreparative HPLC (30% aq. CH3CN) to yield compound 9 (10 mg). Aleuritiside A (1). Colorless gum; [α]D25 −12.1 (c 0.05, MeOH); IR (KBr) νmax: 3360, 2943, 2830, 1448, 1033 cm−1; UV (MeOH) λmax, nm (log ε): 282 (1.40), 228 (3.61); ECD (MeOH) λmax, nm (Δε): 292 (5.3), 248 (3.3), 221 (−2.1); 1H and 13C NMR data

(Phenylamino)pyrimidine-1,2,3-triazole derivatives as analogs of imatinib: searching for novel compounds against chronic myeloid leukemia

• Luiz Claudio Ferreira Pimentel,
• Lucas Villas Boas Hoelz,
• Henayle Fernandes Canzian,
• Frederico Silva Castelo Branco,
• Andressa Paula de Oliveira,
• Vinicius Rangel Campos,
• Floriano Paes Silva Júnior,
• Rafael Ferreira Dantas,
• Jackson Antônio Lamounier Camargos Resende,
• Anna Claudia Cunha,
• Nubia Boechat and
• Mônica Macedo Bastos

Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144

• obtained from the nucleophilic substitution reaction of intermediate 8 in 85% yield. The 1H and 13C NMR spectra of compounds 8 and 9 were similar, but in the IR spectrum of intermediate 9, it was possible to observe the characteristic stretching of the azide group at 2103 cm−1. The 1,3-dipolar

• products 1a,b, and 2a–j, respectively, with 30–84% yields. This last step was adapted from a method already described in the literature [31]. The formation of compounds 1a,b and 2a–j was observed by the disappearance of the characteristic stretching of the azide groups at 2107 and 2103 cm−1 in the IR

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• , MacMillan and co-workers demonstrated an inspiring C(sp3)‒H arylation of dimethylaniline (1a) with a variety of aryl halides using the photoredox nickel catalysis [53]. Here, the combination of the iridium photocatalyst Ir[dF(CF3)ppy]2(dtbbpy)PF6 and the commercially available nickel catalyst NiCl2·glyme

• transfer (HAT) and nickel catalysis [54]. The catalytic system consisting of iridium photocatalyst Ir[dF(CF3)ppy]2(dtbbpy)PF6, nickel catalyst NiBr2·3H2O, ligand 4,7-dimethoxy-1,10-phenanthroline (4,7-dOMe-phen), and 3-acetoxyquinuclidine was found to be optimal to afford the desired α-amino C–C coupled

• (sp3)‒H bonds with aryl tosylates/triflates 11. The relatively less expensive ruthenium photocatalyst Ru(bpy)3Cl2·6H2O was found to be optimal for primary C(sp3)‒H arylations (Scheme 7a), whereas Ir[dF(CF3)ppy]2(dtbbpy)PF6 was the effective photocatalyst for the arylation of secondary C(sp3)‒H bonds

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• and were characterized by IR and GC–MS. All novel pruducts were characterized by IR, 1H NMR, 13C NMR, elemental analysis and GC–MS. The reactions were monitored by TLC using silica gel plates and the products were purified by flash column chromatography on silica gel (Merck; 230–400 mesh), eluting

• with hexane/ethyl acetate (v/v 9:1). NMR spectra were recorded at 500 MHz for 1H and 125 MHz for 13C using Me4Si as the internal standard in CDCl3. GC–MS were recorded on a Shimadzu/ QP2010 Plus spectrometer. IR spectra were recorded on a Mattson 1000 spectrometer. Melting points were determined with a

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• genetically engineered strain [26]. Experimental General experimental procedures Optical rotations were measured using a JASCO DIP-3000 polarimeter. ECD spectra were recorded on a JASCO J-720W spectropolarimeter. UV and IR spectra were recorded on a Shimadzu UV-1800 spectrophotometer and on a PerkinElmer

• ). Nomimicin B (1) Colorless amorphous solid; [α]D23 −29 (c 0.10, MeOH); UV (MeOH) λmax (log ε) 246 (3.83), 293 nm (3.71); ECD (c 9.5 × 10−5, MeOH) λext (Δε) 208 (−5.27), 247 (+3.72), 294 nm (−1.24); IR νmax: 3360, 2965, 1755, 1619, 1408, 1088, 998 cm−1; see Table 1 for 1H and 13C NMR data; HRESITOFMS (m/z

• ): [M + Na]+ calcd for C30H40O8Na, 551.2615; found, 551.2612. Nomimicin C (2) Colorless amorphous solid; [α]D23 −12 (c 0.10, MeOH); UV (MeOH) λmax (log ε) 246 (3.93), 292 nm (3.78); ECD (c 9.7 × 10−5, MeOH) λext (Δε) 208 (−6.63), 246 (+4.08), 298 nm (−1.39); IR νmax: 3380, 2963, 1744, 1618, 1404, 1097

Facile and innovative catalytic protocol for intramolecular Friedel–Crafts cyclization of Morita–Baylis–Hillman adducts: Synergistic combination of chiral (salen)chromium(III)/BF₃·OEt₂ catalysis

• Karthikeyan Soundararajan,
• Helen Ratna Monica Jeyarajan,
• Raju Subimol Kamarajapurathu and
• Karthik Krishna Kumar Ayyanoth

Beilstein J. Org. Chem. 2021, 17, 2186–2193, doi:10.3762/bjoc.17.140

• filtration, the solvent was removed under reduced pressure and the crude product was purified on silica gel (using hexane/EtOAc) to afford the desired product 6a as a white solid (81%). Methyl 1H-indene-2-carboxylate (6a): Yield: 160 mg (81%); white solid; mp 85–87 °C; IR (cm−1): 3062, 2953, 2884, 1947, 1735

• mg (67%); off-white solid; mp 194–196 °C; IR (cm−1): 1674, 1652, 1582, 1568, 1454, 1278, 1117; 1H NMR (CDCl3, 400 MHz) δH 8.31–7.46 (m, 5H, Aro-H), 7.14 (s, 1H, N=CH), 4.56–4.50 (t, J = 8 Hz, 2H, CO-CH2), 2.84–2.79 (t, J = 8 Hz, 2H, N-CH2); 13C NMR (CDCl3, 100 MHz) δC 185.12 (1C, C=O), 133.02–128.83

• purified by column chromatography to afford the corresponding [3 + 2] cycloaddition product 8a in 61% yield. Compound (8a): Yield: 192 mg (61%); yellowish oil; IR (cm−1): 2972, 2254, 1954, 1562, 1671, 1455, 1245; 1H NMR (CDCl3, 400 MHz) δH 7.80–7.06 (m, 9H, Aro-H), 5.90 (s, 1H, HC-N-CO), 4.36–4.21 (m, 2H