Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• cameroonensis, isolated from the root of Trema guineensis, a Cameroonian medicinal plant from the family Ulmaceae [11]. Results Structural elucidation Diaporthe cameroonensis, which showed an interesting high-performance liquid chromatography–diode array detector–high-resolution mass spectrometry (HPLC–DAD–HRMS

• ) profile, was scale up fermented to give 12 g of culture extract. This extract was subjected to a silica gel column chromatography to give several fractions, which were further purified over normal and reversed-phase HPLC to yield 2-ethyl-2,6-dihydroxy-5,7-dimethylbenzofuran-3-one (1), 3,9

• . Experimental General experimental procedures Column chromatography (60.4 cm length × 5.5 cm inner diameter) was carried out on silica gel 230–400 mesh (Merck). Analytical TLC was performed on Merck pre-coated silica gel 60 F254 plates, and spots were detected using ceric sulfate spray reagent and/or diluted

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• -difluoroalkenes and the co-elution of the aniline byproducts during column chromatography with the desired products affected the overall yield of the reaction. For a complete optimization list with all conditions that were screened, see Supporting Information File 1. With the optimized conditions in hand, we

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• elution buffer used for protein purification through Ni2+-NTA affinity chromatography. While domain B alone showed a substantial enzyme precipitation after 12 h at 4 °C, full length 2MIBS did not (Figure 1B), suggesting that the A domain increases enzyme solubility and long-term stability. This effect

• (Karlsruhe, Germany) and used without purification. Solvents for column chromatography were purchased in p.a. grade and purified by distillation. Thin-layer chromatography was performed with 0.2 mm precoated plastic sheets Polygram Sil G/UV254 purchased from Machery-Nagel (Düren, Germany). Column

• chromatography was performed using silica gel 60 (0.040–0.060 nm) purchased from Merck (Darmstadt, Germany). NMR spectra were recorded on a Bruker Avance I 500 MHz spectrometer and a Bruker Avance III HD 700 MHz Cryo spectrometer. Chemical shifts were referenced to the residual proton signal of C6D6 (δ = 7.16

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• reduced pressure to provide the crude product which was then purified by column chromatography on silica gel. 2. Procedure for the air-promoted 1,4-addition of dialkylzinc reagents to α-(aminomethyl)acrylates (preparation of compounds 11–13, 14a–c, and 15a). In a Schlenk-tube under argon, the appropriate

• (MgSO4), and concentrated under reduced pressure to provide the crude product which was then purified by column chromatography on silica gel. 3. Procedure for the air-promoted tandem 1,4-addition–aldol reaction between dialkylzinc reagents, α-(aminomethyl)acrylates and carbonyl derivatives (preparation

• aq NH4Cl (5 mL) at 0 °C. The aqueous layer was extracted with CH2Cl2 (2×). The combined organic layer was washed (brine), dried (MgSO4), and concentrated under reduced pressure to provide the crude product which was then purified by column chromatography on silica gel. Air-promoted radical chain

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• removed under vacuo. The residue was purified by chromatography on silica gel (n-hexane/ethyl acetate 100:1 to 5:1) to give pure compound 5d (243 mg, 69%) as a beige solid. Mp 118.2 °C; Rf 0.50 (n-hexane/ethyl acetate 10:1); 1H NMR (600 MHz, CDCl3) δ 3.68 (s, 3H), 7.02–7.07 (m, 1H), 7.17–7.20 (m, 1H

• organic phases were dried with anhydrous sodium sulfate, filtered, and the solvent was removed under reduced pressure. The residue was purified by chromatography on silica gel (n-hexane/ethyl acetate 20:1 to 5:1) to give compound 6 (184 mg, 42%) as a colorless solid. Mp 204.5 °C; Rf 0.35 (n-hexane/ethyl

• combined organic phases were dried (anhydrous sodium sulfate), filtered, and the solvent was removed under vacuo. The residue was purified by chromatography on silica gel (n-hexane/ethyl acetate 20:1 to 5:1) to give compound 8b (105 mg, 71%) as a colorless solid. Mp 150.8 °C (lit.: 157 °C [38]); Rf 0.58 (n

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• column chromatography to give the coupling product 3. Selected natural products and pharmaceuticals bearing acyloins. Proposed reaction mechanism. Strategies for the synthesis of α-trifluoromethyl acyloins. Substrate scope. Standard conditions: a solution of alkyl carboxylic acid 1 (0.4 mmol), 2 (0.6

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• chromatography. Because 4.6 was obtained in better yields and in only 3 steps, the epimerization of 4.6 to 4.10 was also reported (Figure 4B). This epimerization is achieved in three-step sequence that starts with the double tosylation of 4.6 to produce 4.11. Then, the SN2 reaction with potassium acetate in DMSO

• alcohol. This step was achieved by the deprotonation of 21.3 followed by the reaction with 1-bromooctadecane. Compound 21.4 was purified by chromatography on silica gel followed by a recrystallization in acetone. Deprotonation of the secondary alcohol present in 21.4 followed by the addition of

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• reaction mixture was dried under vacuum to remove DMF. The crude product was extracted with DCM and washed with water. The organic phase was collected and dried with MgSO4, filtered and concentrated under vacuo. The product was further purified by column chromatography (ethyl acetate/hexane 1:4) to give

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• under reflux (for 5a) or in a Dean–Stark apparatus (for 4a). After completion (TLC), the reaction mixture was cooled, washed with brine, and dried. The toluene was removed and the residue was purified by column chromatography on silica gel (acetone/ether 8:2) to give the pure N-substituted imidazole 6a

• mL) was added. The mixture was washed with brine and dried. Finally, the solvent was removed and the residue was purified by column chromatography on silica gel, using acetone/ether as eluent, to give the pure imidazole derivative 8. Medicines containing an imidazole nucleus. Synthesis of N

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• simple flash chromatography. Conclusion An unprecedented methodology for the synthesis of 4,6-disubstituted 5-nitrocyclohexene carbaldehydes with three contiguous stereogenic centers using acetaldehyde as one of the reaction components of an Enders cascade reaction has been developed. The masked form of

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• solvent by rotatory evaporation at reduced pressure, the residue was subjected to column chromatography (silicon gel, 300–400 mesh) with petroleum ether and ethyl acetate (v/v = 1:1) to give the pure product for analysis. Ethyl rel-(3R,3'S,4'R)-1,1''-dibenzyl-5,5''-dichloro-7',7'-dimethyl-2,2'',5'-trioxo

• mixture was heated at 50 °C for seven hours. After removing the solvent by rotatory evaporation at reduced pressure, the residue was subjected to column chromatography (silicon gel, 300–400 mesh) with petroleum ether and ethyl acetate (v/v = 4:1) to give the pure product for analysis. rel-(3R,3'S,4'R)-1,1

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• Varian Cary Eclipse fluorescence spectrophotometer, respectively. The mass spectra were recorded on an Agilent G 6530 AA LC-HRMS QTOF system in positive mode. Spectroscopic grade chloroform was used to measure UV–visible and emission spectra of the samples. Thin-layer chromatography (TLC) was performed

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• chromatography (silica gel, DCM/PE 1:5, v:v). Compound NI-PTZ-F was obtained as orange solid. Yield: 40 mg (15%); mp 136.2–137.2 °C; 1H NMR (CDCl3, 400 MHz) δ 8.87 (d, J = 7.63 Hz, 1H), 8.70 (d, J = 7.25 Hz, 1H), 8.60 (d, J = 8.51 Hz, 1H), 8.00 (d, J = 7.63 Hz, 1H), 7.77–7.81 (m, 1H), 7.29–7.35 (m, 4H), 7.11 (d

• . Synthesis of NI-PTZ-Ph NI-PTZ-Ph was synthesized by a reported method [11][71] similar to that of NI-PTZ-F. The crude product was purified by column chromatography (silica gel, DCM/PE 1:3, v:v). Compound NI-PTZ-Ph was obtained as orange solid. Yield: 243 mg (52%); mp 126.2–127.2 °C; 1H NMR (CDCl3, 400 MHz

• product was purified by column chromatography (silica gel, DCM/PE 1:3, v:v). The product was obtained as orange solid. Yield: 230 mg (80%); mp 100.2–101.5 °C; 1H NMR (CDCl3, 400 MHz) δ 8.87 (d, J = 7.63 Hz, 1H), 8.69 (d, J = 8.38 Hz, 1H), 8.58 (d, J = 8.50 Hz, 1H), 7.98 (d, J = 7.76 Hz, 1H), 7.75–7.79 (m

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• methods were used to purify the extract, such as MCI gel CHP 20, silica gel column, vacuum liquid chromatography, and semi-preparative HPLC purification, to obtain pure compounds. A total of ten compounds, including five new eudesmane-type sesquiterpenoids (1–5), and five known compounds were identified

• Marine Chemical Inc., Qingdao, China), RP-18 silica gel (40–60 µm; Daiso Co., Tokyo, Japan), and MCI gel CHP 20P (75–150 µm, Mitsubishi Chemical Industries, Tokyo, Japan) were used for column chromatography. Optical rotations were measured on an Anton Paar MCP-100 digital polarimeter. UV and CD spectra

• .6.3.1–Fr.6.3.4) by a vacuum liquid chromatography (VLC) on a silica gel column with petroleum ether/acetone (50:1–3:7) as solvents. Fr.6.3.1 (808.5 mg) was subjected to preparative thin-layer chromatography (PTLC) (dichloromethane) to give Fr.6.3.1.1–Fr.6.3.1.7, of which Fr.6.3.1.4 (255.9 mg) was

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• of the desired product by column chromatography, as well as upon recrystallization from ethyl acetate, 1,4-diketone 5а undergoes Paal–Knorr cyclization with the formation of the starting tetrahydrofuro[3,2-c]pyridine 4а, which ultimately leads to mixtures of compounds 4а and 5а with different ratios

The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

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

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• temperature for two hours. After removing the solvent by rotatory evaporation at reduced pressure, the residue was subjected to column chromatography with petroleum ether and ethyl acetate (v/v = 5:1) as eluent to give the pure product for analysis. Trimethyl 4-benzyl-3-methyl-1-phenyl-4,4a,13b,13c-tetrahydro

• acetylenedicarboxylate (0.9 mmol), 5,6-unsubstituted 1,4-dihydropyridine (0.3 mmol) in acetonitrile (5.0 mL) was heated a reflux for three hours. After removing the solvent by rotatory evaporation at reduced pressure, the residue was subjected to column chromatography with petroleum ether and ethyl acetate (v/v = 6:1

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• nitriles 3ba–da in excellent yields. Interestingly, when the loading of CH3COOK was reduced to 2 equivalents, we obtained a mixture of unsaturated nitrile 3aa and saturated nitrile 4 after column chromatography (Scheme 4). We speculated that the reduction of the base equivalent may induce the ionization of

• was not accomplished either by NMR analysis or chromatography. Conclusion In conclusion, we have developed an SO2F2-mediated ring-opening cross-coupling reaction of cyclobutanone oxime derivatives with alkenes for the synthesis of a class of novel elongated nitriles. The newly constructed δ-olefin

First synthesis of acylated nitrocyclopropanes

• Kento Iwai,
• Rikiya Kamidate,
• Khimiya Wada,
• Haruyasu Asahara and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2023, 19, 892–900, doi:10.3762/bjoc.19.67

• mixture by silica gel column chromatography (Scheme 3). In the subsequent reaction of the α-brominated product 6c with nitrostyrene 2a in the presence of triethylamine, the complete consumption of 2a was confirmed, however, the reaction mixture was complicated, and the desired cyclopropane 1c was not

• substrates, almost equal amounts of diastereomers were formed. Whereas 4b was isolated by recrystallization of the reaction mixture from ethanol, the other adducts 4c–g were easily isolated by column chromatography. For comparison with previously reported results, adduct 4b, derived from acetylacetone (3b

• , compound 8b was isolated after column chromatography with 21% yield instead of the desired cyclopropane 1b (Scheme 4). The NMR data for the ring protons of product 8b and compound 1b’ are listed in Table 2. Although the benzene ring in compound 8b is methyl-substituted, a 1H NMR spectrum similar to those

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• quenched by the addition of 1 M HCl (6 mL) and EtOAc (6 mL). Then, the organic phase was washed with a sat. aq. solution of NaHCO3 (6 mL), brine (6 mL), dried over MgSO4, and concentrated under vacuum. The residue was purified by flash chromatography on SiO2 (hexane/EtOAc 15:1). Comparison of DFT

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• . Elemental analyses were performed on a Flash 2000 Organic Elemental Analyser (Thermofisher). For samples containing chlorine, mercurimetric titration was used. IR spectra were recorded on a Nicolet iS50 equipped with an ATR diamond crystal (neat solid samples). Flash chromatography was performed using a

• Büchi Reveleris® X2 flash chromatography system equipped with a UV–vis/ELSD detector and Reveleris Flash pure cartridges (12–40 g, 35–45 μm, 53–80 Å) or puriFlash® Alumine N 32/63 µm cartridges (12 g). The reaction pathways were calculated [41] with the Gaussian 16 rev. C.01 program, using the B3LYP

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• chromatography (CC) was performed using macroporous adsorbent resin Amberlite TM XAD 16N (particle size 20–60 mesh, Rohm and Haas Company), MCI gel CHP 20P (particle size 75–150 μm, Mitsubishi Chemical Industries, Japan), RP-18 (particle size 40–60 μm; Daiso Co.), C-18 silica gel (particle size 40–60 μm; Daiso

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• with ortho-substituted anilines is also reported. The key features of the protocol include the use of a green oxidant, a short reaction time (30 min), chromatography-free isolation, scalability, and economical, delivering N-arylsulfonylimines in excellent yields of up to 96%. While the oxidation of N

• -substituted anilines. The key features including the use of a green oxidant, a short reaction time, chromatography-free isolation, and scalability mark a distinction from the contemporary methods. Although we propose a dual role for SO4·− involving both hydrogen atom abstraction (HAT) and single electron

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• octagon-containing carbo[5]helicene was isolated in a 61% yield, which can be further transformed into other chiral hydrocarbon analogues 12 and 13 [35]. Chiral resolution of these helicenes was accomplished by chiral high-performance liquid chromatography (HPLC) and the isomerization barriers were

• via preparative thin-layer chromatography. The P- and M-isomers of the helical conformation of 115 were separated by chiral HPLC, and the thermal racemization barrier was determined as 44.7 kcal/mol at 260 °C. Campaña and co-workers also reported tropone-containing, four HBC-fused NG 117 [59]. The

• 121 in a high yield. Due to the two conformations of cyclooctatetraene saddles, NG 121 is a chiral structure and optically pure enantiomers were separated using chiral high-performance liquid chromatography (HPLC), which featured a perfect mirror-image circular dichroism (CD) for both enantiomers

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• Supporting Information, File 1, Figure S60). The further alkynylation of compounds 7a–e was carried out using trimethylsilylacetylene and the Pd(PPh3)2Cl2/CuI/Et3N/DMSO catalytic system giving rise to dialkynyl derivatives 10a–e in high yields (Scheme 2). Column chromatography of trimethylsilyl derivatives

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

• Sarot Cheenpracha,
• Ratchanaporn Chokchaisiri,
• Lucksagoon Ganranoo,
• Sareeya Bureekaew,
• Thunwadee Limtharakul and
• Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

• P. macropterum were extracted using MeOH to give a crude extract. After removal of the organic solvent, the extract was separated by repeated silica gel column chromatography as well as by Sephadex LH-20 to afford two new and one known cassane diterpenoids, identified as 12α,14β-dihydroxycassa-13(15

• ) in the deuterated solvents (CDCl3) using TMS as an internal standard. An Agilent 1290 infinity II/Q-TOFMS mass spectrometer was employed to acquire HRESI–TOF–MS spectra. Column chromatography (CC) was carried out on silica gel 60 (70–230 mesh, Merck, Darmstadt, Germany), and Sephadex LH-20 (GE

• Healthcare). Thin-layer chromatography (TLC) was performed on silica gel 60 F254 plates (Merck, Darmstadt, Germany) using precoated aluminum plates for analytical purposes. Plant material Fresh fruits of Pterolobium macropterum Kurz were collected from Song Khwae District, Nan Province, Thailand (GPS: 19