Design and synthesis of a bis-macrocyclic host and guests as building blocks for small molecular knots

• Elizabeth A. Margolis,
• Rebecca J. Keyes,
• Stephen D. Lockey IV and
• Edward E. Fenlon

Beilstein J. Org. Chem. 2020, 16, 2314–2321, doi:10.3762/bjoc.16.192

• appeared to hinder the formation of crystals suitable for X-ray diffraction to prove the topology of the product. The second-generation TLC approach to trefoil knots is presented here. It involves the binding of an electron-poor guest (2 or 3) in an electron-rich host (1) to promote the threading step, an

• were formed (see Scheme S1 in Supporting Information File 1). Repeated attempts to grow X-ray crystals of the product failed. To test for topological chirality, a europium chiral shift reagent was added, but the 1H NMR spectrum was too noisy to discern any peak doubling. Additional experiments, such as

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• , after which the medium-containing MTT was discarded and formazan crystals were dissolved in 150 µL DMSO. The absorbance at 550 nm (with automatic discount of reference wavelength 630 nm) of the resulting solution was measured in a 96-well spectrophotometer microplate reader. The percentage of cell

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• colorless crystals of 128. Along similar lines the crystals of 127 were achieved by following the same procedure. On the other hand, the groups of Amaya and Hirao have reported the synthesis of sumanenyl mono- and trihafnocene complexes 129 and 130, respectively, along with the catalytic activity of 129 for

Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and ⁶Li/¹³C NMR spectroscopic data

• Jürgen Vollhardt,
• Hans Jörg Lindner and
• Hans-Joachim Gais

Beilstein J. Org. Chem. 2020, 16, 2057–2063, doi:10.3762/bjoc.16.172

• and sulfonyl-substituted dilithio methandiide 2a [14][15]. The use of n-BuLi, inadvertently containing Li2O, had yielded prismatic crystals of 2a. An X-ray crystal structure analysis had shown a Ci symmetric hexamer, (2a)6·Li2O·(THF)6, the dianionic C atoms of which are each coordinated by two Li

• mixture of THF and n-hexane with Li2O-free n-BuLi (1.88 equiv) in n-hexane at −90 °C followed by warming the solution to room temperature gave octahedral crystals of 2a. The use of two equivalents of the base led two a slower crystal growth. The X-ray crystal structure analysis showed a chiral C2

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

• Yuqing Wang,
• Gaigai Wang,
• Anatoly A. Peshkov,
• Ruwei Yao,
• Muhammad Hasan,
• Manzoor Zaman,
• Chao Liu,
• Stepan Kashtanov,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

• were able to obtain crystals suitable for the structure determination via X-ray crystallographic analysis. It was found that a part of the substance crystallized in a racemic form while the rest crystallized in an enantiopure form. By resolving both types of crystals [90], the configuration of the

Selective preparation of tetrasubstituted fluoroalkenes by fluorine-directed oxetane ring-opening reactions

• Clément Q. Fontenelle,
• Thibault Thierry,
• Romain Laporte,
• Emmanuel Pfund and
• Thierry Lequeux

Beilstein J. Org. Chem. 2020, 16, 1936–1946, doi:10.3762/bjoc.16.160

• investigated with hydrobromic acid (HBr 33 wt % in AcOH, 2.3 equiv) in diethyl ether (Table 1, entry 4). This reaction proved faster and reached completion after 45 min at 20 °C, giving product 1d with an excellent yield of 94% and an E/Z selectivity of 89:11. The isomers could be separated and crystals of the

• following this two-step method, pure E-1c could be obtained while direct ring opening of 1 with BTSH and CSA resulted in a 25:75 mixture of E/Z-1c. A crystallographic analysis of crystals of Z-25 confirmed the nature and geometry of the obtained product (see Supporting Information File 2). Addition of

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• heterocyclic aldehydes or ketones with methylene succinates followed by subsequent hydrolysis and dehydration processes. Under exposure of solutions or crystals of thus prepared hetaryl(aryl)-substituted dihydrofuran-2,5-diones to UV light, those bearing an isopropylidene fragment attached to the furandione

• : The X-ray diffraction studies of crystals of 3Z, 3E and 9 were performed with a Bruker XSCANS device (λ(Мо Кα) = 0.71073 Å, \w scans). Bond lengths and valence angles of 3Z, 3E and 9 are presented in Tables S1–S3 (Supporting Information File 1). The main crystallographic data and characteristics are

Microwave-assisted efficient one-pot synthesis of N²-(tetrazol-5-yl)-6-aryl/heteroaryl-5,6-dihydro-1,3,5-triazine-2,4-diamines

• Moustafa Sherief Moustafa,
• Ramadan Ahmed Mekheimer,
• Saleh Mohammed Al-Mousawi,
• Mohamed Abd-Elmonem,
• Hesham El-Zorba,
• Afaf Mohamed Abdel Hameed,
• Tahany Mahmoud Mohamed and
• Kamal Usef Sadek

Beilstein J. Org. Chem. 2020, 16, 1706–1712, doi:10.3762/bjoc.16.142

• Labstation at 120 °C for 12 min. The solvent was removed under reduced pressure and the solid product was isolated by filtration and recrystallized from DMF. 6-(4-Chlorophenyl)-N2-(5H-tetrazol-5-yl)-5,6-dihydro-1,3,5-triazine-2,4-diamine (4a). Colorless crystals; mp 320–322 °C; yield 0.268 g, 92%; Rf 0.55 (1

• . calcd for C10H10ClN9: C, 41.17; H, 3.46; Cl, 12.15; N, 43.22; found: C, 41.22; H, 3.42; Cl, 12.11; N, 43.24; EIMS (m/z): 290.1 [M − 1]+. 6-(4-Methoxyphenyl)-N2-(5H-tetrazol-5-yl)-5,6-dihydro-1,3,5-triazine-2,4-diamine (4b). Colorless crystals; mp 306–308 °C; yield 0.255 g, 89%; 1H NMR (600 MHz, DMSO-d6

• ; N, 43.88; found: C, 45.89; H, 4.52; N, 43.90; EIMS (m/z): 286.1 [M − 1]+. 6-Phenyl-N2-(5H-tetrazol-5-yl)-5,6-dihydro-1,3,5-triazine-2,4-diamine (4c). Colorless crystals; mp 317–319 °C; yield 0.277 g, 93%; 1H NMR (600 MHz, DMSO-d6) δ 6.15 (s, 1H), 7.22 (s, 1H), 7.40–7.46 (m, 5H), 8.50 (br s, 1H

Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study

• Csilla Hargitai,
• Györgyi Koványi-Lax,
• Tamás Nagy,
• Péter Ábrányi-Balogh,
• András Dancsó,
• Gábor Tóth,
• Judit Halász,
• Angéla Pandur,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2020, 16, 1636–1648, doi:10.3762/bjoc.16.136

• crystals from derivative 8a were unsuccessful. It has to be emphasized that theoretically, the formation of four dimer-like regioisomers could be expected from aldehydes 1a–d, each of them as the mixture of two diastereomeric racemates. Although HPLC–MS measurements indeed indicated the presence of

Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts

• Soundararajan Karthikeyan,
• Radha Krishnan Shobana,
• Kamarajapurathu Raju Subimol,
• J. Helen Ratna Monica and
• Ayyanoth Karthik Krishna Kumar

Beilstein J. Org. Chem. 2020, 16, 1579–1587, doi:10.3762/bjoc.16.130

• layer was washed with brine and dried over anhydrous MgSO4. The removal of the solvent in vacuo afforded the crude product, which was purified over silica gel (using hexane/EtOAc) to acquire 4a as colorless crystals. Proposed mechanism for the synthesis of 1,4-disubstituted triazoles. Proposed mechanism

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• structure of rotaxane 1a was determined by single crystal X-ray diffraction of crystals obtained by slow evaporation of a dichloromethane solution. The analysis of the X-ray solid-state structure of the rotaxane 1a showed a significant difference to Leigh’s rotaxane I [4]. Rotaxane I only presented two

• ; found, 501.20295. Crystal structure determination Single crystals of rotaxane 1a (C36H42FeN3O3) were obtained by slow evaporation of a dichloromethane solution. A suitable crystal was mounted on a cryoloop with paratone®-N oil on an AFC11 partial Chi goniometer. The data were collected at 120 K on

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• observed that crystals of santonine would shatter when exposed to sunlight [28]. Credit for the pioneering of photochemistry is usually given to Ciamician, the “grandfather of photochemistry”, who reported many interesting transformations of chemical solutions when irradiated by sunlight [29][30]. His

One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• –0.200 mm). High-resolution mass spectra (HRMS) were acquired on a Thermo Scientific, model Q-Exactive high resolution LC–MS/MS with a resolution of up to 150000FWHM at m/z 200. X-ray structure determination: Colorless single crystals of compounds 25 and 26 were obtained from DMSO/H2O. Diffraction data

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• photochemical [2 + 2] cycloaddition reaction was performed both in benzene solution and in the solid state, affording 78% yield with a ratio of syn/trans 8.7:1 and 61% de for syn-isomers at 15 °C in crystals, while no diastereoselectivity could be observed in benzene solution [16] (Scheme 72). In 2001, they

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin

• Margareta Sohora,
• Leo Mandić and
• Nikola Basarić

Beilstein J. Org. Chem. 2020, 16, 1296–1304, doi:10.3762/bjoc.16.110

• '-Hydroxy-5'-oxo-1',2',5',9b'-tetrahydrospiro[cyclohexane-1,3'-pyrrolo[2,1-a]isoindole]-1'-carbonitrile (7): 2 mg (2%), oily crystals; 1H NMR (CD3OD, 600 MHz) δ 7.81 (dd, J = 1.0, 7.6 Hz, 1H), 7.70 (dt, J = 1.3, 7.6 Hz, 1H), 7.65 (dt, J = 1.3, 7.6 Hz, 1H), 7.48 (dd, J = 1.0, 7.6 Hz, 1H), 4.55 (br s, 3H

• ), 3.48–3.42 (m, 1H), 2.65–2.59 (m, 1H), 2.06–2.00 (m, 2H), 1.86–1.78 (m, 2H), 1.53–1.27 (m, 7H); MS m/z (% relative intensity): 282 (100), 283 (18.4), 284 (1.6). 1,3,4,4a,5,11a-Hexahydro-6H-dibenzo[b,e]azepine-6,11(2H)-dione (8): 4 mg (4%), oily crystals; 1H NMR (CD3OD, 300 MHz) δ 7.83–7.77 (m, 1H), 7.71

• , 1C), 30.1 (t, 1C), 26.2 (t, 1C), 23.7 (t, 1C), 21.3 (t, 1C); MS m/z (% relative intensity): 229 (100), 230 (15.1), 231 (1.1). 1,6-Dioxo-1,4,5,6-tetrahydro-2H-spiro[benzo[c]azocine-3,1'-cyclohexane]-5-carbonitrile (9): 3 mg (3%), oily crystals; 1H NMR (CD3OD, 300 MHz) δ 8.19-8.15 (m, 1H), 8.04–8.00 (m

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

• Grzegorz Mlostoń,
• Mateusz Kowalczyk,
• André U. Augustin,
• Peter G. Jones and
• Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

• the slightly more polar one was isolated and identified as the minor isomer of 9d. In the course of crystallization from hexane the less polar fraction gave single crystals suitable for the X-ray diffraction analysis, which unambiguously confirmed that in this molecule the Ph(C-5) and Fc(C-2) groups

• -dicarboxylate (cis-9a): Yield: 159 mg (98%); red crystals; mp 192–193°C; 1H NMR δ 2.65 (dd, JH,H = 13.9 Hz, JH,H = 4.3 Hz, 1H, HC(4)), 3.44 (s, 3H, OCH3), 3.46 (s, 3H, OCH3), 3.56 (dd, JH,H = 13.9 Hz, JH,H = 12.7 Hz, 1H, HC(4)), 3.51–3.60 (m, 1H, HC(Fc)), 4.00–4.02 (m, 1HC(Fc)), 4.07 (s, 5HC(Fc)), 4.27–4.29 (m

• , 5.22; S, 5.93; found: C, 66.58; H, 5.24; S, 5.99. Dimethyl 2,2-diferrocenyl-5-phenyl tetrahydrothiophene-3,3-dicarboxylate (9b): Yield: 54 mg (28%); red crystals; mp 170 °C (dec.); 1H NMR δ 2.91 (dd, JH,H = 14.0 Hz, JH,H = 6.2 Hz, 1H, HC(4)), 3.36 (s, 3H, OCH3), 3.41 (dd, JH,H = 15.8 Hz, JH,H = 12.4 Hz

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• . After completion of the reaction, water was added to the mixture until precipitation appeared. The precipitate was collected by filtration and washed with plenty of water to remove excess CuCl2, NH4OAc, and reduced copper salt. Compound Q1 (1.4 g, 78%) was obtained as yellowish crystals. 1H NMR (400 MHz

• ): Quinazoline derivative (Q1, 0.25 g, 0.79 mmol), 3,6-di-tert-butylcarbazole (0.48 g, 1.7 mmol) and sodium hydride (0.50 g, 1.6 mmol) in dry dimethylformamide (DMF) were used for the nucleophilic substitution reaction. The title compound was obtained as yellowish crystals in a yield of 0.25 g, 37%; Tm = 181 °C

• mmol) and sodium hydride (0.50 g, 1.6 mmol) in dry dimethylformamide (DMF) were used for the nucleophilic substitution reaction. The title compound was obtained as yellowish crystals in a yield of 0.10 g, 21%; Tm = 233 °C; 1H NMR (400 MHz, CDCl3) δ 8.93 (s, 2H), 8.11 (s, 2H), 7.89-7.84 (s, 4H), 7.56 (s

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• immediately after vacuum drying suggested that some structural parameters, such as the water content, varied in the two analyses. The final proof that the phase change was due to some water molecules escaping the crystal, and this proof came from the X-ray diffraction analysis of heated crystals of F-1 (with

• of 15–30 μm. SEM imaging of crystals of F-1 in the F-1a phase formed from a DMSO/water system indicated the existence of two types of crystals (Figure 4). Type 1 was a set of platelets with heights of 0.7–1 mm, grown from a common planar base with a diameter of 0.1–0.3 mm. In other words, the

• crystals were a typical druse setup. Type 2 were well-formed, nonisotropic crystals with two parallel planes in varying sizes (0.3 × 0.4 × 1 mm). The thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) of F-1 was conducted to examine its thermal properties. The TGA curve of the bulk

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• universal attenuated total reflectance (UATR) accessory made of thallium bromide-iodide crystals (KRS-5). The 1H, 13C{1H} and 19F NMR spectra were recorded on Bruker Avance-300 and -400 spectrometers (δ in ppm; J in Hz). All spectra were recorded at room temperature in solution, using CDCl3 as deuterated

• emitting diodes (LEDs) were purchased from Topbright. X-ray crystallography Single crystals of 2c and 4a of suitable quality for X-ray diffraction measurements were grown by slow diffusion of n-pentane into CH2Cl2 solutions of the crude product at –18 °C for several weeks. One selected single crystal was

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• . Carbazole (1) was first brominated with N-bromosuccinimide in dimethylformamide [32][33]. This gave a mixture of mono- and dibromo products 2 and 3. Upon crystallisation 3-bromocarbazole (2) was obtained as white crystals in good yield. 3-Bromocarbazole (2) was then alkylated with 1-bromohexane in 50

• reduced pressure the crude product was obtained as a brown solid. After crystallisation of the crude product with chloroform, the pure product 2 (692 mg, 47%) was obtained as white crystals. Rf (ethyl acetate/hexane, 1:6 v/v): 0.43; melting point: 200–201°C; 1H NMR (600 MHz, CDCI3) δ (ppm) 8.19 (d, J

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• transition (Tg) was noticed at 86 °C, followed by an exothermic crystallization (Tcr) signal observed at 183 °C to obtain crystals, which melted at 201 °C. The crystalline sample of derivative 3 demonstrated a similar behavior. It melted upon the first heating at 174 °C and exhibited a glass transition at Tg

• (250 mL) with vigorous stirring. After filtration and crystallization from methanol compound 2 was obtained as white crystals. Yield (0.60 g, 80%); mp 83–84 °C; 1H NMR (400 MHz, CDCl3) δ 7.46 (d, J = 2.3 Hz, 2H), 7.30 (dd, J = 8.7, 2.3 Hz, 2H), 6.84 (d, J = 8.7 Hz, 2H), 3.98 (q, J = 7.0 Hz, 2H), 1.48

• and the product extracted with dichloromethane. The obtained crude product was purified by column chromatography using ethyl acetate/n-hexane 1:20 as the eluent, recrystallized from the mixture of eluent to afford the target compound 3 as white crystals (0.15 g, 50%). Mp 170–171 °C; 1H NMR (400 MHz

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• annulation was favorable for the formation of six-membered rings. Nevertheless, the existence of several rotamers of 1 derived from the restricted rotation of the peripheral phenyl ring substituents and its nonplanar geometry prevented the structure elucidation by proton NMR analysis [35]. Single crystals of

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• material was purified via column chromatography using silica gel. The BODIPY dimer 7 was prepared using 6 [38] and was obtained as a fluorescent orange solution or as pink-orange crystals in a 30% yield. Similarly, the Pd-catalyzed Sonogashira cross-coupling reaction [39] was successful for the reaction

• extend this family of triptycene-linked porphyrins from dimers to trimers. Single crystal X-ray analyses To further confirm the structures of the substituted triptycene, we obtained single crystals suitable for analysis of the disubstituted triptycenes 5 and 16. The structure of 5 was solved with one

• the porphyrin rings are both possible. However, due to the sever 74.1(7)° rotation between the two 24-atom mean planes of the porphyrin macrocycles and the space occupied by the triptycene, creating a hetero π-stacking would form larger voids in the crystals structure. This would be less favored than

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• ]. Crystallization of derivative 14c from D2O brought the expected results. The analysis confirmed the structure of the resulting compound 14c. The absolute configuration of 14c is consistent with the stereochemistry we proposed based on NMR studies. The crystals of 14c contained the (1R,2S)-diastereoisomer (Figure

• the calculated positions and refined as ‘riding model’ with the isotropic displacement parameters set at 1.2 (1.5 for methyl and hydroxy groups) times the Ueq value for appropriate non-hydrogen atom. As the crystals were obtained from D2O solution, this solvent was used for final model (although, no

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• the external aromatic ring of the indenopyrene using various types of o-bromo arylaldehydes. Related to our study on buckybowl-containing liquid crystals [19], we planned to introduce alkoxy groups on the 1 framework. Here, we report the synthesis and characterization of dimethoxy derivative 5a and

• dependent on the temperature as shown in Table 1. It is assumed that the ring-rotation process, which generated the regioisomer did not occurred in case of 4a because of two larger methoxy groups than the methylenedioxy group. Crystal structures of 5a–c Single crystals of 5a–c were successfully obtained by

• crystals [19]. Experimental General All experiments with moisture- and air-sensitive compounds were performed in anhydrous solvents under nitrogen atmosphere in flame-dried glassware. All reagents were purchased from commercial sources and used without further purification unless otherwise noted. The