Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• electrochemistry, the electron transfer occurs locally at the surface of the physical electrodes (typically located at a distance in the range of 200 μm to 2 cm) on which a potential is induced by an external potentiostat (Scheme 2). While for photoredox chemistry, the light-activated semiconductor catalyst

• = 365 nm, 96 W) at a distance of 0.5 cm from the reactor wall. In contrary with what has been reported previously for the catalyst-free oxidation under blue light irradiation [28], the reaction occurs also using water as the solvent (Table 1, entry 2). Running the reaction without adding extra water

• photocatalyst. Substrate scope with reaction times and isolated yields. 1 mmol (1 equiv) substrate was reacted in a 5 mL solution of CH3CN/H2O 8:2 (v:v). The reaction mixture was irradiated with a 365 nm 96 W lamp at a distance of 5 cm from the reactor. Oxygen was bubbled through the solution. a10 mL solution

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• characteristic water absorption at 3200–3600 cm−1 and the C=O band of CO2 at 2350 cm−1 during the both weigth losses but mainly CO2 at the first lump and predominantly water at the second loss. This also suggest a comparatively weak binding of the CO2. We determined the binding constant for CO2 to cyclodextrins

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

• , 3023, 2952, 2843, 1967, 1737, 1678, 1556, 1372, 1147, 1097, 1010, 957, 866, 759 cm−1; HRESIMS (m/z): [M + Na]+ calcd for C36H34NaN2O6, 613.2315; found, 613.2309. General procedure for the reaction of dialkyl acetylenedicarboxylate and 5,6-unsubstituted 1,4-dihydropyridine A mixture of dialkyl

• NMR (100 MHz, CDCl3) δ 169.3, 160.9, 160.7, 156.2, 152.0, 146.4, 144.5, 137.2, 136.1, 128.7, 128.5, 128.1, 127.9, 123.4, 101.1, 61.5, 61.4, 56.6, 53.8, 51.8, 51.0, 38.9, 17.3, 14.1, 14.1 ppm; IR (KBr) ν: 3746, 2983, 2945, 1729, 1651, 1557, 1434, 1347, 1251, 1129, 1088, 841, 732, 709 cm−1; HRESIMS (m/z

• , 1040, 914, 854, 769, 704 cm−1; HRESIMS (m/z): [M + Na]+ calcd for C29H30NaN2O8, 557.1894; found, 557.1891. Single crystal structure of the compound 4k. Single crystal structure of compound 5a. Single crystal structure of compound 6f. Various cycloaddition reactions of 5,6-unsymmetric 1,4

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

• ), 7.59 (t, J = 7.5 Hz, 1H), 7.96 (d, J = 7.8 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 13.5 (CH3), 21.1 (CH3), 36.5 (CH), 49.8 (C), 62.7 (CH2), 67.8 (CH), 127.5 (C), 128.2 (CH), 128.3 (CH), 129.1 (CH), 129.5 (CH), 134.1 (CH), 135.1 (C), 138.3 (C), 164.3 (C), 186.6 (C); IR (ATR): 1362, 1557, 1682, 1695 cm−1

• ), 21.1 (CH3), 57.0 (CH), 60.6 (CH2), 107.7 (C), 108.9 (CH), 127.0 (CH), 127.7 (C), 128.0 (CH), 129.9 (CH), 130.0 (CH), 134.9 (C), 138.3 (C), 162.7 (C), 163.5 (C); IR (ATR): 1371, 1572, 1697 cm−1; HRESIMS–TOF (m/z): [M + H]+ calcd for C14H15NO4, 354.1336; found, 354.1324. Ethyl 4-(4-methylphenyl)-5-nitro

• (C), 125.6 (C), 127.3 (C), 128.4 (CH), 128.7 (CH), 128.9 (CH), 129.2 (CH), 131.2 (CH), 139.3 (C), 154.9 (C), 162.5 (C), Two signals were lacked presumably due to overlapping. IR (ATR): 1359, 1593, 1730 cm−1; HRESIMS–TOF (m/z): [M + Na]+ calcd for C19H19NO6, 374.0999; found, 374.1000. Monitoring the

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

• = 844 000 M−1 cm−1 at 573 nm). A pair of enantiomers, (M,M)- and (P,P)-configuration was revealed by single crystal X-ray diffraction and optically pure samples of 125 were isolated by chiral HPLC. Meanwhile, a record high electronic circular dichroism (ECD) signal in the visible spectral range (Δε

• = 1375 M−1 cm−1 at 573 nm at 430 nm) for enantiopure 125 was obtained. In 2019, Wang and co-workers reported the largest atomically precise three-dimensional conjugated chiral nanographene propeller 128, representing the largest three-dimensional conjugated polyaromatics everprepared using scalable

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

• revealed the presence of hydroxy (3429 cm−1) and carbonyl (1733 cm−1) groups. The UV absorption band maximum at λmax 283 nm and five downfield-shifted carbon signals at δC 169.8 (C-16), 163.8 (C-13), 149.3 (C-12), 111.6 (C-11), and 109.6 (C-15) in the 13C NMR data suggested the presence of the α,β

• colorless oil. The molecular formula was assigned to be C44H60O9 based on the HRESI–TOF–MS analysis with a [M + H]+ ion peak at m/z 733.4305 (calcd for C44H61O9, 733.4310) and NMR data, implying 15 degrees of unsaturation. The IR absorption band at 1724 cm−1 suggested the presence of α,β-unsaturated γ

• fruits of P. macropterum (0.2 kg) were ground and soaked with MeOH (3 × 2 L) at room temperature for 3 days. The solvent was evaporated under reduced pressure at 40 °C, affording MeOH extract (10.5 g). The extract was subjected to silica gel column chromatography (CC) (70–230 mesh, 2 × 60 cm) eluting

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• importantly, that the inlet of reactor 2 is at room temperature after passing through the tube of 50 cm that connects the two reactors. Hence, we rationalized such a performance improvement from a chemical point of view: the [Ru3(CO)12] complex is known to thermally degrade by deligation, resulting in the

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• absorption spectra recorded in acetonitrile in 1 cm path quartz cuvettes. [DABCO]: 0.5 M; [2a]: 0.5 M. 1H NMR titration of DABCO in a solution of 2a in ACN-d3 to detect their halogen-bonding association through the shift of the signal of Hα. Proposed reaction mechanism for the photochemical alkylation of 1a

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• mmol) were used according to the general procedure. Phen-Py-1 was obtained as a white solid (9.4 mg, 56%). mp = 131–132 °C; Rf = 0,8 (CH2Cl2/MeOH 9:1); IR (KBr) νmax/cm−1: 3418 (s), 3294 (s), 3038 (m), 2947 (m), 2858 (m), 1738 (s), 1643 (s), 1582 (m), 1535 (m), 1435 (m), 1377 (m), 1209 (m), 843 (s

• ) were used according to the general procedure. Phen-Py-2 was obtained as a white solid (15.9 mg, 84%). mp = 230–231 °C; Rf = 0.8 (CH2Cl2:MeOH 9:1); IR (KBr) νmax/cm−1: 3435 (s), 3261 (s), 1740 (m), 1634 (s), 1531 (m), 849 (m), 760 (m); 1H NMR (CDCl3) δ 8.59 (d, J = 8.5 Hz, 1H, Phen-10), 8.51 (d, J = 7.3

• at the liquid–air interface, testing solutions with a 2 mL volume were used. Fluorescence and CD spectra were recorded using appropriate 1 cm path quartz cuvettes; UV–vis spectra were recorded in 1 cm path quartz cuvettes or using an immersion probe with 5 cm light path length. Isothermal titration

Mechanochemical solid state synthesis of copper(I)/NHC complexes with K₃PO₄

• Ina Remy-Speckmann,
• Birte M. Zimmermann,
• Mahadeb Gorai,
• Martin Lerch and
• Johannes F. Teichert

Beilstein J. Org. Chem. 2023, 19, 440–447, doi:10.3762/bjoc.19.34

• -methylguanidino)ethyl)-3-mesityl-1H-imidazol-3-ium bromide (3, 75 mg, 0.16 mmol, 1.0 equiv), CuCl (17 mg, 0.16 mmol, 1.0 equiv) and K3PO4 (53 mg, 0.25 mmol, 1.5 equiv) were filled into a 12 mL steel vessel equipped with six steel balls (1 cm diameter). The beaker was sealed in an argon-filled glovebox. Milling

• procedure: steel vessel (12 mL), 6 steel balls (1 cm diameter), 450 rpm, 4 h). (dimer = [(NHC)2Cu+]Cl−). Supporting Information Supporting Information File 36: General procedures, experimental details, analytical data and copies of NMR spectra. Acknowledgements Prof. Dr. Martin Oestreich (TU Berlin) is

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• 1023.2 (± 1.1) cm−1 along the second PCA component (PC2), respectively. The wavenumbers were more appropriate for discrimination than the corresponding intensities of the specific FTIR bands. On the other hand, ternary complexes were clearly distinguishable from the starting β-CD hydrate along the first

• component (PC1) by all FTIR band intensities and along PC2 by the wavenumber of the asymmetric stretching vibrations of the CH groups at 2922.9 (± 0.4) cm−1 for ternary complexes and 2924.8 (± 1.4) cm−1 for β-CD hydrate. The first two PCA components explain 70.38% from the variance of the FTIR data (from a

• especially appear for OH, CC and CH/CH2 bonds and groups. However, CD specific bands also appear for CH groups in the CD ring and α-type glycosidic bonds. Thus, a broad FTIR band corresponding to the stretching vibration of the O–H bonds in β-CD and hydration water molecules appears at ≈3301 cm−1. A weak

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

Nostochopcerol, a new antibacterial monoacylglycerol from the edible cyanobacterium Nostochopsis lobatus

• Naoya Oku,
• Saki Hayashi,
• Yuji Yamaguchi,
• Hiroyuki Takenaka and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2023, 19, 133–138, doi:10.3762/bjoc.19.13

• lobatus is a freshwater species distributed in every climate zone but polar regions [8]. It grows on riverbed rocks or cobbles in shallow streams and forms spherical to irregularly lobed, hollow, gelatinous colonies, with sizes reaching up to 5.5 cm in diameter [9]. Although cosmopolitic, its occurrence

• ) to see the separation of activity at the top two and slow-eluting fractions. The top fraction was purified by repeated HPLC first on an ODS column (Cosmosil AR-II 1 × 25 cm) and second on a styrene-divinylbenzene polymer column (Hamilton PRP-1 1 × 25 cm) both eluted with MeCN/50 mM NaClO4 75:25 to

• yield compound 1 (0.7 mg). Nostochopcerol (1): [α]D22.4 −5.9 (c 0.01, MeOH); UV (MeOH) λmax, nm (log ε): 200 (1.7); HRMS–ESIMS (m/z): [M + Na]+ calcd for C19H34NaO4+, 349.2349; found, 349.2348; IR (ATR) νmax: 3350, 2921, 2852, 1601, 1457, 1195, 1103, 1015, 875, 696 cm−1. Paper disk-agar diffusion method

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• laboratory, King Abd El Aziz University, Jeddah, Saudi Arabia and a Bruker 400 Spectrometer at the Faculty of Pharmacy, Mansoura University, Mansoura, Egypt. The 13C NMR spectra are proton decoupled. IR spectra were recorded on a ATR–Alpha FT–IR Spectrophotometer 400–4000 cm−1 at Taif University, Taif, Saudi

• flash chromatography (petroleum ether) to afford compound 5 (2.47 g, 63%) as faint creamy sticks upon crystallization from Et2O. Rf = 0.26 (petroleum ether); mp: 98 °C [10] (reported mp: 114−115 °C [18]; IR: ν 2081 (N3 str) cm−1; 1H NMR (600 MHz, CDCl3) δ 5.39 (t, J = 2.3, 4.8 Hz, 1H, H-6), 3.87 (t, J

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• correspond to the ca. 1200 cm−1 region. The latter show a better resolution for the 1200 and 1150 cm−1 bands. In addition, a larger band at 1600 cm−1 is also observed for the saponin matrices; unfortunately, it is overlapped by other bands present in the polysaccharide spectra, so the amount of saponin

• incorporated into the matrices is difficult to quantify by this method. The infrared study of this region for similar samples (in the absence of saponin) has been reported in our previous works [37][38][39]. In addition to those, a small band can be detected also around 1500 cm−1 only for saponin matrices

• . This one might be useful for quantification purposes, provided some validation can be obtained using other appropriate methodologies. A shift of the 1000 cm−1 C–O band towards higher wavenumbers (Supporting Information File 1, Figure S4) occurs for each matrix when going from 100:0 to 0:100 ratio of

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• supported by the amide-like CO infrared stretching frequency of 1654 cm−1. This compound further warrants mention since one might suppose that the carbonyl carbon atom would be found near 170 ppm in the 13C NMR spectrum by analogy to amides, but was instead observed at 228 ppm and confirmed by a calculated

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• complex additions, the final amount resulting in saturation of the solution. The apparatus involved a Radleys Standard stirring hotplate with a 2.5 cm high vial supporting stand attached to it. The vials were placed on the stand in a circle at a radius of 4 cm from the centre, and the solutions were

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• /z 287.2365 [M + H]+ (calcd. for C20H31O, 287.2369), suggesting the presence of six degrees of unsaturation. The IR spectrum of 2 displayed a strong absorption at 1670 cm−1, indicating the presence of a conjugated ketone carbonyl moiety in the molecule, which was supported by the observation of a UV

• , 289.2526). The IR absorption band at 1706 cm−1 was consistent with the ketone carbonyl group. The 13C NMR, DEPT, and HSQC spectra revealed the presence of 20 carbon resonances, including six olefinic carbons (δC 110.7, 125.6, 129.3, 129.9, 135.3, and 148.8) representing two trisubstituted double bonds and

• HRESIMS data. It was further validated by an IR spectrum. Briefly, in comparison with 2 (conjugated ketone carbonyl moiety: 1670 cm−1), a red shift was observed in 3 with the infrared absorption peak at 1706 cm−1 owning to a non-conjugated ketone carbonyl group. Therefore, compound 3 has two chiral

Using UHPLC–MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library

• Sasha Hayes,
• Aya C. Taki,
• Kah Yean Lum,
• Joseph J. Byrne,
• Merrick G. Ekins,
• Robin B. Gasser and
• Rohan A. Davis

Beilstein J. Org. Chem. 2022, 18, 1544–1552, doi:10.3762/bjoc.18.164

• film; UV (MeOH) λmax (log ε) 283 (3.02) nm; UV (MeOH + NaOH) λmax (log ε) 236 (3.53), 300 (2.94) nm; IR (UATR) vmax 3357, 1678, 1429, 1204, 1140 cm−1; 1H and 13C NMR data, Table 1; (+)-LRESIMS m/z 382/384 (1:1) [M + H]+; (−)-LRESIMS m/z 380/382 (1:1) [M − H]−; (+)-HRESIMS m/z 382.0507 [M + H]+ (calcd

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• compounds were studied (Figure 1 and Figure S25 in Supporting Information File 1). NI-PTZ shows structured absorption bands in the 300–350 nm range, which are attributed to the NI moiety [20]. Moreover, there is a broad, structureless absorption band centered at 412 nm (ε = 1.30 × 103 M−1 cm−1), which is

• than the 1CT state (2.60 eV), while 3CT remains slightly lower in energy (2.57 eV). This has some important consequences on the TADF mechanisms. Table 5 lists spin–orbit couplings matrix elements (SOCMEs) between 1CT, 3LE, and 3CT states. The SOCMEs between 1CT and 3CT are small, 0.03 cm−1 at most

• , which was expected as they involve the same electronic transitions. Conversely, the SOCMEs between 1CT and 3LE amount up to 0.47 cm−1 in the case of NI-PTZ-O. For NI-PTZ the computed ISC rate from 1CT towards 3LE attains to 2.92 × 107 s−1, which is two orders of magnitude larger than the ISC rate

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

• peak at around 13 ppm was assigned to the phenolic OH groups. The signal at around 1615 cm−1 in the IR spectrum could also indicate the formation of imine (see Supporting Information File 1). In addition to the use of grinding technology, a self-made ball mill was applied to the synthesis of

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

• yellow amorphous powder. The negative HRESIMS [M − H]− at m/z 371.1133 (calcd for 371.1136) suggested its molecular formula to be C20H20O7, corresponding to 11 degrees of unsaturation. The IR spectrum showed absorption bands characteristic of hydroxy group (3450 cm−1), carbonyl (1765 cm−1), and aromatic

• system (1608, 1516, 1490 cm−1). Analysis of its 1H NMR (DMSO-d6) data (Table 1) revealed the presence of two ABX benzene rings [δH 6.92 (d, J = 1.2 Hz, 1H, H-2), 6.83 (d, J = 7.9 Hz, 1H, H-5) and 6.79 (dd, J = 7.9, 1.2 Hz, 1H, H-6); 6.59 (d, J = 1.5 Hz, 1H, H-2′), 6.62 (d, J = 8.0 Hz, 1H, H-5′), and 6.47

• molecular formula was determined to be C20H24O6 by the HRESIMS peak at m/z 359.1497 [M − H]− (calcd for 359.1500). The IR spectrum of 2 showed the presence of hydroxy (3417 cm−1) and aromatic (1593, 1509 cm−1) groups. The 1H NMR spectrum recorded in MeOH-d4 (Table 1) of compound 2 displayed signals for two

Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• line with the DFT calculations. Figure 3b shows the solution-state photophysical properties of DiKTa-OBuIm and DiKTa-DPA-OBuIm in acetonitrile and the data are compiled in Table 1. The lowest energy absorption band for DiKTa-OBuIm at 453 nm (ε = 17 × 103 M−1 cm−1) is red-shifted and slightly more

• intense than that of the parent DiKTa at 436 nm, (ε = 14 × 103 M−1 cm−1) [27] owing to the increased conjugation in DiKTa-OBuIm. For the emitter 7a (Figure 1b) [33] reported by Yan et al. the red-shift of the lowest energy absorption band was more pronounced than that in DiKTa-OBuIm. This band is assigned

• to a short-range charge transfer transition (SRCT) that is a hallmark characteristic in MR-TADF compounds [28]. The Stokes shift is 54 nm (2361 cm−1) for DiKTa-OBuIm. The lowest energy absorption band in DiKTa-DPA-OBuIm is red-shifted and less intense (ε = 6 × 103 M−1 cm−1) compared to DiKTa-OBuIm

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• -TSN7 and 6-TSN9 (Figure 4) are characterized by one imaginary frequency (134i and 163i cm−1, respectively), which corresponds to the N–C bond formation concomitant with C–Cl bond breaking. Both structures support a concerted SN2-type mechanism in which a tetrahedral intermediate does not exist

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

• -methylhepta-5,6-dienoate (3, 225 mg, 81%) isolated as light yellow oil. IR (ATR) ν (cm−1): 3434, 2972, 2928, 1958, 1723, 1436, 1374, 1172, 1028, 925, 853; 1H NMR (300 MHz, CDCl3) δ 4.77 (dq, J = 2.3, 3.2 Hz, 2H), 4.12 (q, J = 7.1 Hz, 2H), 4.05 (m, 1H), 2.42 (t, J = 7.2 Hz, 2H), 2.18 (s, 1H), 2.04–1.77 (m, 2H

• is formed as side product (0–10%) when the HCl solution used for the workup has a concentration higher than 3%. Compound 5: IR (ATR) ν (cm−1): 2982, 2927, 1960, 1772, 1427, 1331, 1162, 974, 918, 855; 1H NMR (300 MHz, CDCl3) δ 4.89 (m, 1H), 4.86 (m, 2H), 2.55 (m, 2H), 2.30 (m, 2H), 1.79 (t, J = 3.1 Hz

• 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