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

• ]. Since their discovery, researchers have investigated several Co–salen complexes for the KR of epoxides with phenols as nucleophiles (Figure 1) [18][19]. Kim et al. described a catalytic system of a chiral Co–salen immobilized on meso/macroporous silica monoliths for the ring opening of epoxides [20

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

• Chirascan-plus CD spectrometer (Applied Photophysics Ltd., UK). NMR spectral data were measured on a Bruker DRX-600 spectrometer. Silica gel (200–300 mesh, Qingdao Haiyang Chemical Co. Ltd., China) was used for column chromatography. Semi-preparative HPLC was performed on an Agilent 1260 liquid

• /H2O, 5–95%, v/v) to give fractions 1–5. Fr. 2 (58 g) was subjected to silica gel column chromatography (CC) eluting with CH2Cl2/MeOH 9:1 to yield six major fractions (1–6). Fr. 2.2 (0.5 g) then was further purified by preparative HPLC (MeOH/H2O 28:72) to afford compound 5 (20.5 mg) and compound 6

• (13.7 mg). Fr. 2.5 (7.50 g) was further purified by silica gel CC with (CH2Cl2/MeOH 9:1) to give compound 4 (120.5 mg). Fr. 3 (37 g) was further purified by reversed-phase chromatography (RP-18 column) using MeOH/H2O 4:6 to afford compound 1 (4.8 mg). Fr. 4 (21 g) was chromatographed on a silicagel

Synthesis of meso-pyrrole-substituted corroles by condensation of 1,9-diformyldipyrromethanes with pyrrole

• Baris Temelli and
• Pinar Kapci

Beilstein J. Org. Chem. 2022, 18, 1403–1409, doi:10.3762/bjoc.18.145

• hertz (Hz). IR spectra were recorded on FTIR spectrometer (Thermo Scientific, Nicolet IS10). HRMS were measured in ESI mode and the mass analyzer of the HRMS was TOF (Agilent 6224 TOF LC–MS). Flash column chromatography was performed on silica gel (230–400 mesh). 5-Substituted dipyrromethanes [35] and

• the silica column to remove Cu(OTf)2. The solvent was removed under reduced pressure and the crude product was purified by flash column chromatography over silica gel with CH2Cl2/hexane (1:1). Synthesis of 3 and 4 by [2 + 2] MacDonald coupling reaction A solution of 5-phenyl-1,9-diformyldipyrromethane

• residue. The mixture was refluxed for 12 h. The solvent was removed under reduced pressure and the crude product was purified by flash column chromatography over silica gel with CHCl3/hexane (1:1). 1H NMR spectrum of 2a in THF-d8. Electronic absorption spectrum of 2a in CHCl3. Synthetic studies to obtain

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

• under argon. Acetonitrile, dichloromethane, DMSO, DMF and toluene were distilled over calcium hydride under argon. All other reagents were used as received. Chromatographic purifications refer to flash chromatography on silica gel. 1H NMR spectra were measured at 250, 300, 360 or 400 MHz using CDCl3 as

• aqueous CuSO4 solution (4 × 10 mL) and saturated aqueous NH4Cl solution (3 × 10 mL), then dried (MgSO4), filtered and concentred under reduced pressure. The residue was purified by filtration through a short plug of silica gel, eluting with ethyl acetate. Concentration under reduced pressure gave the pure

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

• n-BuLi at −78 °C. This afforded protected anomeric phosphate 16, confirmed by 1H and 13C NMR data (H1 δH 6.01 ppm, 3JH1–P = 6.7 Hz, 3JH1–H2 = 1.8 Hz; C1 δC 96.1 ppm, 2JC1–P = 5.9 Hz). Following an initial purification of 16 using silica gel flash chromatography, the material was crystallised using a

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

• temperatures up to 110 °C. For thin-layer chromatography (TLC) DC-Alufolien Kieselgel 60 F265 (Merck, Darmstadt, Germany) silica gel plates were used. Carbonization in 50% sulfuric acid was used to detect the substances. An eluent mixture propanol/water/25% aqueous ammonia/ethyl acetate 6:3:1:1 (EM1) was used

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

• ) was treated in a 1:1 ratio with [FeCp(η6-C6H5CH3)][PF6] at 160 °C in diglyme. Evaporation of diglyme at reduced pressure and extraction of the product with toluene, followed by filtration through silica, resulted in 3,4,5-tris(3-chlorophenyl)-1,2-diphosphaferrocene (8b) in 68% yield and high purity

Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure

• Irene Torres-García,
• Josefa L. López-Martínez,
• Rocío López-Domene,
• Manuel Muñoz-Dorado,
• Ignacio Rodríguez-García and
• Miriam Álvarez-Corral

Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132

• anhydrous MgSO4, and concentrated under reduced pressure. The residue was purified by silica gel flash column chromatography (n-hexane/EtOAc 9:1) to afford ethyl 3-(3-methyl-2,5-dihydrofuran-2-yl)propanoate (2, 57 mg, 88%) isolated as colorless oil. IR (ATR) ν (cm−1): 2969, 2927, 2849, 1731, 1442, 1376

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization

• Sebastien Curpanen,
• Per Reichert,
• Gabriele Lupidi,
• Giovanni Poli,
• Julie Oble and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131

• sensitive towards silica gel column chromatography, and all of our attempts to isolate it failed. For this reason, we went on to consider C3–Si functionalization strategies of alcohols 4c–7c relying on the formation of cyclic siloxanes and subsequent in situ cross-coupling. We first briefly investigated Pd

• brine, dried over MgSO4, filtered, concentrated under reduced pressure, and purified by silica gel column chromatography. Procedure for the addition of Grignard reagents to C3-silylated furfurals (preparation of compounds 5c, 6c, and 7c) In a flame-dried round-bottom flask under argon was placed the

• reduced pressure. and purified by silica gel column chromatography. Procedure for the Pd/Cu-catalyzed arylation of C3-benzyldimethylsilyl-substituted 2-furyl carbinol 4c (preparation of compounds 18 and 19) A flame-dried Schlenk tube was charged with CuI (20 mol %) and Pd2(dba)3 (2.5 mol %) and heated

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

• cm; immersed 1.8 cm into solution). A constant current electrolysis was performed at room temperature. After application of the desired amount of charge, the electrolysis was stopped, and the solvent was removed in vacuo. The residue was purified by silica gel column chromatography (CH2Cl2). (a

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• commercial instruments (Bruker Avance 300 MHz, Bruker Avance II+ 500 MHz, or Bruker Avance II+ 600 MHz) and chemical shifts (δ) are reported in parts per million (ppm) referenced to tetramethylsilane (TMS) or the internal (NMR) solvent signals. For column chromatography, 70–230 mesh silica 60 (E. M. Merck

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• (from Vapourtec) [29][30][31][32]. To decrease the optical density of the bed, the column was loaded with a mixture of poly-5,5’-di(9H-carbazol-9-yl)-2,2’-bipyridine (poly-czbpy), glass beads and silica [33]. Once the column was ready, nickel was ligated to the polymerized ligand to afford the

Radical cation Diels–Alder reactions of arylidene cycloalkanes

• Kaii Nakayama,
• Hidehiro Kamiya and
• Yohei Okada

Beilstein J. Org. Chem. 2022, 18, 1100–1106, doi:10.3762/bjoc.18.112

• ). Then, the solution was diluted with water and extracted with EtOAc. The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. Yields were determined by 1H NMR analysis using dibromomethane as an internal standard. Silica gel column chromatography (hexane/ethyl acetate

• analysis using dibromomethane as an internal standard. Silica gel column chromatography (hexane/ethyl acetate) gave the corresponding spiro ring compound. Plausible mechanism of the radical cation Diels–Alder reaction (EDG: electron-donating group). Landscape of the radical cation Diels–Alder reaction

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

• -phenyl derivatives and a series of six novel N-thiazolyl derivatives was obtained in 10–70% and 12–35% yield, respectively, after stirring the o-chlorinated arylhydrazones, CuI, KOH, and 1,10-phenantroline for 12–48 hours in DMF at 120 °C. The products were isolated by column chromatography on silica gel

• resealable screw-cap Schlenk flask (≈10 mL volume) in the presence of a Teflon-coated magnetic stirring bar. TLC analyses were performed with Al plates covered with silica gel (SiliCycle, F254) and visualized by UV detection. Silica gel (Vetec, 0.063–0.200 mm, 70–230 mesh) was used for column chromatography

• %), CuI (0.019 g, 20 mol %), and DMF (2.5 mL) were successively added under N2 atmosphere. The reaction mixture was stirred and heated at 120 °C for 12–48 h (see Table 1). After cooling to room temperature, AcOEt (10 mL) was added to the mixture. This was passed through a short column with silica gel 60

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

• , and then, the solution was extracted with dichloromethane. The dichloromethane extract was dried over anhydrous MgSO4, filtrated, and concentrated. The residue was chromatographed on silica gel (ethyl acetate/hexane 1:4 ) to give OTK-2 (19 mg, yield 27%) and OTT-2 (9 mg, yield 14%) as a light yellow

New azodyrecins identified by a genome mining-directed reactivity-based screening

• Atina Rizkiya Choirunnisa,
• Kuga Arima,
• Yo Abe,
• Noritaka Kagaya,
• Kei Kudo,
• Hikaru Suenaga,
• Junko Hashimoto,
• Manabu Fujie,
• Noriyuki Satoh,
• Kazuo Shin-ya,
• Kenichi Matsuda and
• Toshiyuki Wakimoto

Beilstein J. Org. Chem. 2022, 18, 1017–1025, doi:10.3762/bjoc.18.102

• Streptomyces sp. RM72 were first partitioned by water and ethyl acetate, and then the organic layer was further fractionated by silica gel column chromatography. Fractionation by reversed-phase HPLC yielded ten compounds (1–10) that generate N2H4 upon acid hydrolysis. The combination of 1H and 13C NMR with a

Isolation and biosynthesis of daturamycins from Streptomyces sp. KIB-H1544

• Yin Chen,
• Jinqiu Ren,
• Ruimin Yang,
• Jie Li,
• Sheng-Xiong Huang and
• Yijun Yan

Beilstein J. Org. Chem. 2022, 18, 1009–1016, doi:10.3762/bjoc.18.101

• spectrometer with TMS as an internal standard. HRMS–ESI data were obtained through an Agilent 1290 UPLC/6540 Q-TOF mass instrument. Column chromatography (CC) was performed using silica gel (30–400 mesh, Qingdao Marine Chemical Inc., China), Sephadex LH-20 (25–100 µm, Pharmacia Biotech Ltd., Sweden), and MCI

• , the extract was purified by silica gel chromatography and semipreparative HPLC to yield daturamycin A (1) (4.5 mg), daturamycin B (2) (1.8 mg), daturamycin C (3) (8.7 mg), terferol (4) (2.4 mg), BTH-II0204-207: D (5) (2.1 mg), betulinan A (6) (6.2 mg). Identification of new compounds Daturamycin A (1

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

• selected as the LAG agent keeping all other parameters the same. Interestingly, the monobrominated product 2a was obtained almost exclusively in an excellent yield (91%) within just 5 min of grinding (Table 1, entry 6). The attempted model reaction under solid-state grinding using silica gel was sluggish

• Agate mortar–pestle. In each case, once the reaction got over, the crude product was directly slurried by the addition of silica gel (230–400 mesh, approximately 1 g) and purified by flash chromatography eluting with varying proportions of EtOAc/petroleum ether; thus, a typical work-up step was avoided

• conversion was observed, 0.8–1 g of silica gel (230–400 mesh) was added and the slurry was subjected to flash chromatography and eluted with a mixture of EtOAc/petroleum ether to afford the pure monobromo phenol derivative. The side product succinimide was subsequently eluted using MeOH/CHCl3 1:10

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

• Daniele Rocco,
• Ana A. Folgueiras-Amador,
• Richard C. D. Brown and
• Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• was added to the catholyte and the mixture was left under ultrasound irradiation for 30 minutes. The solvent was removed under reduced pressure and the residue was purified by column chromatography on silica gel. The first experiment (Table 1, entry 1) was carried out using stainless steel as cathode

• Sigma-Aldrich and Alfa Aesar and used as received. All air/moisture sensitive reactions were carried out under an inert atmosphere, in oven-dried or flame-dried glassware. TLC was performed on aluminium plates precoated with silica gel 60 with an F254 indicator; visualized under UV light (254 nm) and/or

• by staining with potassium permanganate. Flash column chromatography was performed using high purity silica gel, pore size 60 Å, 230–400 mesh particle size, purchased from Merck. 1H NMR and 13C NMR spectra were recorded in CDCl3 (purchased from Cambridge Isotope Laboratories) at 298 K using a Bruker

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• Shimadzu IRAffinity-1 infrared spectrometer. HRMS were measured on a Thermo Scientic Exactive FTMS spectrometer. Melting points were uncorrected. Column chromatography was performed on silica gel 60. THF was distilled from sodium benzophenone ketyl radical. TMSCl, TEA, and DMF were distilled from CaH2

• by column chromatography on silica gel (hexanes/EtOAc) to give 146 mg of 7a [23] (78% yield) as a mixture of two diastereomers (78:22 dr). A solution of 7a (146 mg) and PPTS (10 mg) in toluene (10 mL) was refluxed using the Dean–Stark apparatus under nitrogen atmosphere for 1 h. After removal of the

• solvent in vacuo, the residue was purified by column chromatography on silica gel (hexanes/EtOAc) to give 95 mg of 3a [8][23] (56% yield in two steps). Electroreductive coupling of phthalic anhydrides with α,β-unsaturated carbonyl compounds and subsequent treatment with 1 M HCl (previous work

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

• previously reported [13], the separation (by any mean) of the 2-hydroxypyrazine isomers 3 and 4 is challenging. To overcome this, we used water-heated columns and preheated eluent mixtures (see the experimental part) which allowed to run chromatography over silica gel at 60 °C. At this temperature and using

• tetraalkylammonium hydroxides as bases does improve the reaction yield, especially when starting from phenylalanine amide (2{2}). Moreover, the recourse to chromatography over silica gel at 60 °C was a crucial experimental setting to properly separate and characterize the two isomers occurring. Mechanism-wise the

• , respectively. Shifts (δ) are given in ppm with respect to the TMS signal and cross-coupling constants (J) are given in hertz. Column chromatography was performed either on Merck silica gel 60 (0.035–0.070 mm) or neutral alumina containing 1.5% of added water using a solvent pump and an automated collecting

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• solvent signals, and coupling constants (J) were in Hz. HRESIMS spectra were recorded on an Agilent G6520 Q-TOF mass spectrometer, while HREIMS spectra were recorded on a Finnigan-MAT-95 mass spectrometer (Thermo Fisher Scientific, Waltham, USA). Commercial silica gel (Qingdao Haiyang Chemical Group Co

• (80.1 mg) was purified by RP-HPLC (65% MeOH in H2O, 3.0 mL/min) to give 4 (2.7 mg, tR = 16.2 min). The subfraction C2 (66.5 mg) was successively separated by silica gel CC (PE/Et2O 5:1 to 1:1) and RP-HPLC (75% MeCN in H2O, 3.0 mL/min) to give 3 (3.6 mg, tR = 9.8 min). The subfraction E (34.9 mg) was

Synthesis and HDAC inhibitory activity of pyrimidine-based hydroxamic acids

• Virginija Jakubkiene,
• Gabrielius Ernis Valiulis,
• Markus Schweipert,
• Asta Zubriene,
• Daumantas Matulis,
• Franz-Josef Meyer-Almes and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 837–844, doi:10.3762/bjoc.18.84

• Melting points were determined in open capillaries with a digital melting point IA9100series apparatus (ThermoFisher Scientific). All reactions and purity of the synthesized compounds were monitored by TLC using silica gel 60 F254 aluminum plates (Merck). Visualization was accomplished by UV light. Column

• chromatography was performed using silica gel 60 (0.040–0.063 mm) (Merck). NMR spectra were recorded on a Bruker Ascend 400 spectrometer (400 MHz and 100 MHz for 1H and 13C, respectively). 1H NMR and 13C NMR were referenced to residual solvent peaks. High-resolution mass spectrometry (HRMS) analyses were carried

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• ]. Column chromatography was carried out on silica gel (300–400 mesh). Analytical thin-layer chromatography was performed on glass plates of silica gel GF-254 with detection by UV. Standard techniques for synthesis under inert atmosphere and Schlenk glassware equipped with an 8 mm PTFE vacuum stopcock, were

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• employed Stewart–Grubbs catalyst 71 is completely decomposed but its decomposition products could efficiently be removed by passing the reaction mixture through a cartridge containing a mixture of silica and charcoal providing 72 in 32% yield at a productivity of 0.2 g/h. The macrocycle 72 was already