A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• -acetyl-ʟ-Tyr-ʟ-Pro-ʟ-Trp, was determined by a combination of spectroscopic analyses, chemical derivatization, ECD calculation, and DFT-based theoretical chemical shift calculation, revealing the presence of an (Sa)-axial chirality around the biaryl bond. Compounds 2–4 lacked hydroxylation on the side

• comparison of experimental and simulated ECD spectra [26][27]. Quite interestingly, the DFT calculation suggested that 1a and 1b would possess the opposite axial chirality around the biaryl bond between C-6 and C-7'': Ra for 1a and Sa for 1b as dominant atropisomers (Figure 4). This conformational difference

• around the biaryl axis was likely caused by the steric repulsion between the acetamido group at C-2 and the H-5' methylene protons, by which the H-2 methine proton was directed in close proximity toward the H-5' protons. The experimental ECD spectrum of 1 displayed intense negative and positive Cotton

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

• Ken-ichi Nakashima,
• Junko Tomida,
• Takao Hirai,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

• planar structures of 1 and 2 were elucidated by extensive spectroscopic analyses. Furthermore, the absolute configurations of 1–4 were determined by single-crystal X-ray diffraction and electronic circular dichroism spectroscopy (ECD). In addition, the crystallographic data for 5 were updated for the

• determination of the absolute configuration of 1–4 by single-crystal X-ray diffraction and ECD spectroscopy. In addition, we also updated the crystallographic data for glauconic acid (5), a known nonadride. Results and Discussion Talaromyces sp. ECN211 was isolated from healthy leaves of Selaginella tamariscana

• ); δC 64.2) instead of the aromatic methyl signals observed for 1 (Table 1). Therefore, C-11 was proposed to be an oxymethylene group, which was also confirmed by HMBC correlations (Figure 2) from the oxymethylene unit to C-2 (δC 109.3), C-3 (δC 150.7), and C-4 (δC 104.3). Since the ECD data of 2 were

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• -forming S. aureus. The structure elucidation and determination of the absolute configuration were accomplished using a combination of spectroscopy, including 1D and 2D NMR, HRMS, Mosher ester analysis, and comparison of calculated/experimental ECD spectra. A chemotaxonomic investigation of the secondary

• ) were not elucidated previously. Therefore, electronic circular dichroism (ECD) measurements combined with time-dependent density functional theory (TDDFT) calculations of ECD data of compound 1 in MeOH at the B3LYP/6-311+G* level of theory were carried out. The CD spectrum of 1 showed strong Cotton

• effects: a first negative at 274 nm (Δε −196) and a positive second one at 252 nm (Δε +203), indicating the helicity of the 6-6′ axis as aR, according to the exciton chirality method [13]. Furthermore, the TDDFT-ECD calculations were performed on three isomers, namely (3R,3′R,6R)-1, (3S,3′S,6S)-1, and (3S

Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• stacking interactions, in addition to hydrogen bonding, with the aromatic rings adopting a high degree of parallelism, as seen in crystal packings and ECD data. Furthermore, π–bromine interactions between the bromine atom of the aryl substituents and the triazole units might also contribute to an overall

• hydroxymethyl group in position 6 in the gg rotamer, likely linked through hydrogen bonds. Electronic circular dichroism (ECD) is a powerful technique to study supramolecular systems [20][21], since many interactions responsible for the presence of CD Cotton effects occur through space, such as the well-known

• ECD exciton chirality method [22][23][24]. ECD of compound 10 in a DMSO/H2O (1:2, v/v) solution and in gel form were successfully measured (Figure 6). ECD of the solution exhibited negative first/positive second exciton Cotton effects at 262 (Δε = −8.6) and 242 nm (Δε = +3.3), respectively (Figure 6

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• (Sterlitech corp., Kent, WA). The device is sealed by six hex bolts size M3. General experimental procedures Optical rotations were measured with a Jasco DIP 140 polarimeter. ECD spectra were taken on a Jasco J-810 CD spectropolarimeter. UV and IR spectra were obtained using Perkin-Elmer Lambda 40 and Perkin

α-Photooxygenation of chiral aldehydes with singlet oxygen

• Dominika J. Walaszek,
• Magdalena Jawiczuk,
• Jakub Durka,
• Olga Drapała and
• Dorota Gryko

Beilstein J. Org. Chem. 2019, 15, 2076–2084, doi:10.3762/bjoc.15.205

• dichroism (ECD) and TD-DFT methods. Keywords: 1,2-diols; ECD; enamines; organocatalysis; porphyrins; silyl ethers of diarylprolinols; singlet oxygen; Introduction Carbonyl compounds are one of the most important building blocks in organic synthesis. As a consequence, there is a constant need for new

• anti’-6 obtained from the reaction with diarylprolinol silyl ether (R)-18 (Table 1, entry 5) were analyzed using electronic circular dichroism spectroscopy (ECD) and TD-DFT methods. So-called in situ methodology with dimolybdenum tetraacetate (19) acting as auxiliary chromophores which proved a very

• useful tool in solving stereochemical problems [24][25][26], allowed to determine the absolute configuration at the C2 carbon atom of obtained diols (Scheme 5) [27][28]. In this method the achiral Mo complex 19 forms optically active complexes with chiral vic-diols allowing the application of ECD to

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• -13 were α-oriented. The absolute configuration of 1 was determined to be 1R,3R,6S,7R,13S by comparison of the experimental electronic circular dichroism (ECD) spectrum with time-dependent density functional theory (TDDFT)-calculated ECD spectra of the two possible enantiomers of 1 (Figure 4

• investigation of the proton coupling constants (Table 1), NOESY correlations (Figure 3) and ECD spectra (Figure 4). The configuration at C-9 was not determined. Hence, structure 2 was determined as shown in Figure 1. Bipolenin M (3) was purified as a colourless oil. The molecular formula C15H22O3 was based on a

• coupling constants (Table 1), NOESY correlations (Figure 3) and ECD spectra (Figure 4). Bipolenin N (4) was acquired as a colourless oil. Its molecular formula was determined to be C15H28O4 from the HRESIMS [M + H − 2H2O]+ ion at m/z 237.1859 (calcd for C15H25O2+, 237.1849). The UV–vis spectra of 1–3

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• , respectively. Other parameters include the following: a sweep width of 12 000 Hz, 32 K data points. The data were processed using Varian DOSY software [26]. ECD spectra were recorded on ECD Jasco J-715 spectropolarimeter. 2,8,14,20–Tetraisobutylresorcin[4]arene was obtained according to a literature procedure

Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

• Sven Götz,
• Andreas Schneider and
• Arne Lützen

Beilstein J. Org. Chem. 2019, 15, 1339–1346, doi:10.3762/bjoc.15.133

• phase (Figure 1). This simple procedure was successfully used for the semi-preparative separation of 156 mg of (rac)-1. It was possible to separate more than 25 mg substance per injection giving both enantiomers of 1 in an enantiomeric excess of >99%. Electronic circular dichroism spectra (ECD) were

• from a couple of days at 40 °C to only a few hours at 70 °C in ethanol which sets the limits for further derivatization. a) Chromatogram of an analytical separation of (rac)-1 on a CHIRALPAK IB column as the stationary phase and MeOH as the mobile phase, 298 K, flow rate: 0.5 mL min−1; b) ECD-spectra

Correction: Varioloid A, a new indolyl-6,10b-dihydro-5aH-[1]benzofuro[2,3-b]indole derivative from the marine alga-derived endophytic fungus Paecilomyces variotii EN-291

• Peng Zhang,
• Xiao-Ming Li,
• Xin-Xin Mao,
• Attila Mándi,
• Tibor Kurtán and
• Bin-Gui Wang

Beilstein J. Org. Chem. 2018, 14, 2394–2395, doi:10.3762/bjoc.14.215

• benzenoid derivatives; cytotoxicity; marine alga-derived fungus; Paecilomyces variotii; TDDFT-ECD calculation; The authors wish to rename compounds 1 and 2 (shown in Figure 1 of the original article [1]) as varioloids C and D, respectively (Figure 1), as the synonyms varioloids A and B have already been

Synthesis and in vitro biochemical evaluation of oxime bond-linked daunorubicin–GnRH-III conjugates developed for targeted drug delivery

• Sabine Schuster,
• Beáta Biri-Kovács,
• Bálint Szeder,
• Viktor Farkas,
• László Buday,
• Zsuzsanna Szabó,
• Gábor Halmos and
• Gábor Mező

Beilstein J. Org. Chem. 2018, 14, 756–771, doi:10.3762/bjoc.14.64

• formaldehyde (e.g., from the softeners of the plastic tubes) not only during the reaction steps (cleavage, ligation) but also under the HPLC purification conditions which has a high impact on the yield [35]. Secondary structure determination by electronic circular dichroism spectroscopy ECD spectra of GnRH-III

• influence of ECD spectra from the exchange of D-Asp to D-Glu. The ECD spectra of all four GnRH-III peptide conjugates reveal two distinct bands: one negative at 200 nm and one positive at 235 nm (Figure 1, Supporting Information File 1, Figures S15 and S16). The negative band is also present in the GnRH-III

• peptide without the daunorubicin (Dau) part. This indicates that the main conformational preferences are not changed by the conjugation. The shapes of the ECD curves show a highly dynamic peptide structure in water. This is in agreement with the NMR study made by Pappa et al. that presented an extended

Polarization spectroscopy methods in the determination of interactions of small molecules with nucleic acids – tutorial

• Tamara Šmidlehner,
• Ivo Piantanida and
• Gennaro Pescitelli

Beilstein J. Org. Chem. 2018, 14, 84–105, doi:10.3762/bjoc.14.5

• compatible conditions and are extensively time consuming. Therefore, in search for faster methods which can be applied to conditions that are at least similar to the naturally occurring ones, a set of polarization spectroscopy methods has shown highly promising results. Electronic circular dichroism (ECD) is

• the most commonly used method for the characterization of the helical structure of DNA and RNA and their complexes with ligands. Less common but complementary to ECD, is flow-oriented linear dichroism (LD). Other methods such as vibrational CD (VCD) and emission-based methods (FDCD, CPL), can also be

• of these methods are found in structural studies of biomacromolecules [3]. For instance electronic circular dichroism (ECD), the most commonly used method, is indispensable in the structural studies of proteins and also intensively used in the characterization of the helical structure of DNA and RNA

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydroanhydrocycloheximides

• Li Yang,
• Ping Wu,
• Jinghua Xue,
• Huitong Tan,
• Zheng Zhang and
• Xiaoyi Wei

Beilstein J. Org. Chem. 2017, 13, 1039–1049, doi:10.3762/bjoc.13.103

• , anhydroisoheximide (4), cycloheximide (5), and isocycloheximide (6), were obtained from the cultures of Streptomyces sp. SC0581. Their structures were elucidated by extensive spectroscopic analysis in combination with theoretical conformational analysis and ECD computations. The photoinduced interconversion between

• , anhydroisoheximide (4) [6], together with cycloheximide (5) and isocycloheximide (6) [10]. Their structures were elucidated by spectroscopic analysis, theoretical conformational analysis, and ECD/TDDFT calculations. The photoinduced interconversion between 2 and 3 was observed and verified, and the possible reaction

• conformers of both stereoisomers were subjected to TDDFT calculations of the electronic circular dichroism (ECD) spectra. As shown in Figure 3, the calculated ECD spectra of (4R,6R,αS)-1 and (4R,6R,αR)-1 were similar to one another and both in good agreement with the measured spectrum of 1, which indicated a

The effect of cyclodextrin complexation on the solubility and photostability of nerolidol as pure compound and as main constituent of cabreuva essential oil

• Joyce Azzi,
• Pierre-Edouard Danjou,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2017, 13, 835–844, doi:10.3762/bjoc.13.84

• ). The total energy difference (ΔE, kJ/mol) between the inclusion complex and the sum of their individual components in their optimized fundamental states was calculated (ΔE = ECD/Ner – (ECD + ENer)) and used as the theoretical parameter to evaluate the complexation energy of the inclusion complex. NMR

Secondary metabolome and its defensive role in the aeolidoidean Phyllodesmium longicirrum, (Gastropoda, Heterobranchia, Nudibranchia)

• Alexander Bogdanov,
• Cora Hertzer,
• Stefan Kehraus,
• Samuel Nietzer,
• Sven Rohde,
• Peter J. Schupp,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2017, 13, 502–519, doi:10.3762/bjoc.13.50

• protection strategy within the scarcely investigated aeolidoidean genus Phyllodesmium. Experimental General experimental procedures Optical rotations were measured with a Jasco DIP 140 polarimeter. ECD spectra were taken on a Jasco J-810 CD spectropolarimeter. UV and IR spectra were obtained using Perkin

Characterization of the synthetic cannabinoid MDMB-CHMCZCA

• Carina Weber,
• Stefan Pusch,
• Dieter Schollmeyer,
• Sascha Münster-Müller,
• Michael Pütz and
• Till Opatz

Beilstein J. Org. Chem. 2016, 12, 2808–2815, doi:10.3762/bjoc.12.279

• and comparison of the data with DFT calculations, while ECD spectroscopy was found to be inconclusive in this case. The enantiomeric purity of samples from test purchases and police seizures was assessed by a self-developed chiral HPLC method. Keywords: chiral HPLC; ECD spectroscopy; NPS; synthetic

• samples. For this purpose, we used analytical methods such as NMR, tandem mass spectrometry, vibrational and electronic circular dichroism spectroscopy (VCD and ECD), as well as chiral HPLC. Results and Discussion Pure MDMB-CHMCZCA (3) was obtained as a so-called “research chemical” (RC) from an online RC

• CO and/or a cyclohexyl radical or methylenecyclohexane. As MDMB-CHMCZCA bears a stereogenic center at C-1', the elucidation of the absolute configuration of the sample was attempted by ECD spectroscopy. While the UV spectra can be adequately predicted by TD-DFT calculations (time-dependent density

Biomimetic synthesis and HPLC–ECD analysis of the isomers of dracocephins A and B

• Viktor Ilkei,
• András Spaits,
• Anita Prechl,
• Áron Szigetvári,
• Zoltán Béni,
• Miklós Dékány,
• Csaba Szántay Jr,
• Judit Müller,
• Árpád Könczöl,
• Ádám Szappanos,
• Attila Mándi,
• Sándor Antus,
• Ana Martins,
• Attila Hunyadi,
• György Tibor Balogh,
• György Kalaus (†),
• Hedvig Bölcskei,
• László Hazai and
• Tibor Kurtán

Beilstein J. Org. Chem. 2016, 12, 2523–2534, doi:10.3762/bjoc.12.247

• Dracocephalum rupestre, have been synthesized in a one-pot reaction. The separation of 2a–d and 3a–d was achieved by preparative HPLC. The four stereoisomers of each natural product were separated by analytical chiral HPLC and their absolute configuration was studied by the combination of HPLC–ECD measurements

• and TDDFT–ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies. Keywords: absolute configuration; Dracocephalum rupestre; dracocephins A–B; ECD calculation; flavonoid alkaloids; HPLC–ECD; Introduction Flavonoid

• racemates (2a, 2c/2b, 2d; 3a, 3c/3b, 3d) by HPLC–ECD analysis (Figure 1). The planar structure and absolute configuration of the first-eluted stereoisomer of dracocephins A (±)-2a–d was determined by single-crystal X-ray diffraction analysis as (2R,5”S)-2a [2]. The biosynthesis of these flavonoid

Determination of the absolute stereostructure of a cyclic azobenzene from the crystal structure of the precursor containing a heavy element

• Reji Thomas and
• Nobuyuki Tamaoki

Beilstein J. Org. Chem. 2016, 12, 2211–2215, doi:10.3762/bjoc.12.212

• enantiomer formed by the reductive debromination. In the previous study with the combination of density functional theoretical calculations (DFT) and electronic circular dichroism (ECD), we have assigned the first and second eluted enantiomers of (E)-2 as R-(−)-(E)-2 and S-(+)-(E)-2, respectively, on a

New furoisocoumarins and isocoumarins from the mangrove endophytic fungus Aspergillus sp. 085242

• Ze’en Xiao,
• Senhua Chen,
• Runlin Cai,
• Shao’e Lin,
• Kui Hong and
• Zhigang She

Beilstein J. Org. Chem. 2016, 12, 2077–2085, doi:10.3762/bjoc.12.196

• configuration of compound 2 was unambiguously determined by X-ray structure analysis and ECD calculation. Moreover, the absolute configurations of compounds 3–5 were assigned by comparison of their ECD spectra with isocoumarins described in the literature. Asperisocoumarins C and D (3 and 4) were fully

• ) [16][17], which allowed the assignment of the absolute configuration of 2 as (2R,3R,7R) (Figure 3). Moreover, the predicted ECD curves of 2 and its relevant enantiomer were computed at the [B3LYP/6-31 G(2d,p)] level, and the experimental ECD curve of 2 agreed well with the predicted one (Figure 4), in

• at δC 167.2 were observed, whereas two oxygenated methine carbons at δC 94.5 and 71.0 were absent in the spectrum of compound 3. These differences were further supported by the HMBC correlations of olefinic proton H-3 to C-2, C-3a and C-9b (Figure 2). By comparison of the ECD spectrum (Figure 5) and

Varioloid A, a new indolyl-6,10b-dihydro-5aH-[1]benzofuro[2,3-b]indole derivative from the marine alga-derived endophytic fungus Paecilomyces variotii EN-291

• Peng Zhang,
• Xiao-Ming Li,
• Xin-Xin Mao,
• Attila Mándi,
• Tibor Kurtán and
• Bin-Gui Wang

Beilstein J. Org. Chem. 2016, 12, 2012–2018, doi:10.3762/bjoc.12.188

• time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculations. A similar compound, whose planar structure was previously described but the relative and absolute configurations and 13C NMR data were not reported, was also identified and was tentatively named as

• varioloid B (2). Both compounds 1 and 2 exhibited cytotoxicity against A549, HCT116, and HepG2 cell lines, with IC50 values ranging from 2.6 to 8.2 µg/mL. Keywords: bisindolyl benzenoid derivatives; cytotoxicity; marine alga-derived fungus; Paecilomyces variotii; TDDFT-ECD calculation; Introduction The

• NOE correlation between H-2 and 3-OMe led to recognition that these protons adopt cis orientation. In order to elucidate the absolute configuration of 1, solution TDDFT-ECD protocol [14][15] was carried out on the arbitrarily chosen (2R,3R) enantiomer. The preliminary conformational search at MMFF

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• . Similarly, H-13 unveiled the same interactions with H-1 and H-9 while H-14 correlated with H-8 (Figure 4). In order to determine the absolute configuration of the compounds 1–3, ECD spectra prediction was used [36][37]. The absolute configuration of 1 was assigned as 2R, 6S, 7R, 10R, and 11S by ECD analysis

• similar interactions with H-1 (δ 1.72) and H-9 (δ 1.56, 1.67). The absolute configuration of 2 was determined to be 2R, 3S, 6S, 7R, and 10S by ECD analysis. As compound 1, two Cotton Effects (CE) from the n→π* transition of the α,β-unsaturated lactone were revealed at 225 and 275 nm with alternative signs

• aglycone [39]. The absolute configuration of 3 was assigned as 1R, 6R, 7S, and 10S. Three CE's were observed on the experimental ECD spectrum at 240, 305 and 350 nm due to the n→π* transition of the α,β-unsaturated ketone. The foregoing data led to identify 3 as 6-hydroxyguaiane congener (Figure 2) and the

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• yielded the individual enantiomers (10R,11R)- and (10S,11S)-hydnocarpin D (2a, 2b). We measured optical rotations and ECD and confirmed the proposed structures (see Figures S3 and S4 in Supporting Information File 1). To our knowledge, this is the second case only [22] that these two enantiomers were

Chiroptical properties of 1,3-diphenylallene-anchored tetrathiafulvalene and its polymer synthesis

• Masashi Hasegawa,
• Junta Endo,
• Seiya Iwata,
• Toshiaki Shimasaki and
• Yasuhiro Mazaki

Beilstein J. Org. Chem. 2015, 11, 972–979, doi:10.3762/bjoc.11.109

• undergoes slow photoracemization even in daylight, the present allene is totally configurationally stable under ordinary conditions. Each isomer possesses pronounced chiroptical properties in its ECD spectra reflecting the chiral allene framework. Moreover, the elongation of the chiral main chain was also

• systems having strong chiroptical properties because they have great potential for use in optical devices involving polarized light [1][2][3]. Chiral response, in electronic circular dichroism (ECD) based on an exciton coupling between two adequate π-chromophores, can express a pronounced chiroptical

• orientation of the chromophores [8][9]. We recently introduced 1,3-bis(tetrathiafulvalenyl)allene derivatives 1, as a new class of chiral electrochromic (EC) materials consisting of redox-active chromophores and a non-centrochiral framework (Figure 1) [10]. The intensive Cotton effect on the ECD spectra is

Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

• László Tóth,
• Yan Fu,
• Hai Yan Zhang,
• Attila Mándi,
• Katalin E. Kövér,
• Tünde-Zita Illyés,
• Attila Kiss-Szikszai,
• Balázs Balogh,
• Tibor Kurtán,
• Sándor Antus and
• Péter Mátyus

Beilstein J. Org. Chem. 2014, 10, 2594–2602, doi:10.3762/bjoc.10.272

• . Separated enantiomers of the products were characterized by HPLC-ECD data, which allowed their configurational assignment on the basis of TDDFT-ECD calculation of the solution conformers. Two compounds showed neuroprotective activities against hydrogen peroxide (H2O2) or β-amyloid25–35 (Aβ25–35)-induced

• cellular injuries in human neuroblastoma SH-SY5Y cells in the range of those of positive controls. Keywords: 1,4-benzoxazepine; diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization; neuroprotective; tert-amino effect; TDDFT-ECD calculation; Introduction The 1,4-benzoxazepine structural

• ,b were separated on a Chiralpak IA column using hexane/dichloromethane as eluent and online HPLC-ECD spectra of the separated enantiomers were recorded. Due to their similar chromophoric system, the HPLC-ECD spectra of 7a and 7b were quite similar. The first-eluting enantiomer of 7a had an intense

Effect of cyclodextrin complexation on phenylpropanoids’ solubility and antioxidant activity

• Miriana Kfoury,
• David Landy,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2014, 10, 2322–2331, doi:10.3762/bjoc.10.241

• ) leading to two different orientations of the aromatic ring inside the host cavity. The total energy difference (ΔE, kJ/mol) between inclusion complexes and the sum of their individual components in their optimized fundamental states was calculated (ΔE = ECD/PP – (ECD + EPP)) and used as the theoretical