The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• stereoselective labelling experiments using (E)-(4-13C,4-2H)IPP (blue H = 2H) and (Z)-(4-13C,4-2H)IPP (red H = 2H), and (R)-(1-13C,1-2H)IPP (blue H = 2H) and (S)-(1-13C,1-2H)IPP (red H = 2H). Black dots indicate 13C-labelled carbons. Labelling experiments on the biosynthesis of patchoulol (3, part 1). Black dots

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• Supporting Information File 1, Tables S4 and S5 for details). A plausible mechanism for the aldehyde arylation is presented in Scheme 3 based on previous literature reports [19][26][33][34] and our mechanistic investigation experiments. Upon blue light irradiation, the photocatalyst is excited generating the

•  3. The energy profiles also show that when the solvent effect is included (blue lines), the RC and RP structures become less stable relative to the isolated reactants and products. As a result, for the DABCO cation radical, the reaction barrier relative to the RC structure is 14.07 kcal·mol−1, lower

• results while the blue lines are for the PCM single points from the gas phase optimized geometry. RC – reactants complex; PC – product complexes. On both graphs the structure shown on the left represents the RC, on the right, PC and the top centre structure is for the TS between DABCO and the aldehyde. TS

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• addition, the UV–vis spectrum in Figure 4a shows that the absorbance of TBT keeps on the decrease (ΔA = 0.623) without red shift or blue shift in the presence of Q[8]. Both of the above phenomena show that Q[8] interacted with the “arm” of TBT and produced precipitation due to aggregation, which is also

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• %, with Commission Internationale de l’Éclairage coordinate of (0.22, 0.47), at 1 mA cm−2. Keywords: blue emitters; dimer; indolocarbazole; orientation; outcoupling effect; solution-processed OLEDs; TADF emitters; triazine; Introduction Organic thermally activated delayed fluorescence (TADF) materials

• mA cm−2. The 20 wt % ICzTRZ-based OLEDs exhibited a slightly higher EQEmax of 11.6% and blue-shifted emission with λEL of 485 nm. This result is consistent with that of the photophysical measurements for 20 wt % TADF emitter:CzSi films (ΦPL = 57% and λPL = 488 nm for DICzTRZ, ΦPL = 63% and λPL = 475

• % doped CzSi film of DICzTRZ emits in the blue at 488 nm and shows a photoluminescence quantum yield of 57.1%. The ΦPL of DICzTRZ is slightly lower than that of ICzTRZ (63% under N2 [14]), in line with its lower computed oscillator strength. DICzTRZ shows both prompt and delayed fluorescence, with a τp

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• ) nickel- and (C) palladium complexes. Blue and yellow surfaces represent the solvent accessible surface of ligands with a probe radius of 1.4 Å. Hydrogen atoms are omitted for clarity. Main geometrical features and the relative energies (in kcal mol–1) of (A) ligand L3, (B) nickel- and (C) palladium

• complexes. Blue and yellow surfaces represent the solvent accessible surface of ligands with a probe radius of 1.4 Å. Hydrogen atoms not involved on hydrogen–bonding interactions are omitted for clarity. Synthetic route for the preparation of L1-M, L2-M and L3-M complexes. Antibacterial and antituberculosis

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• electron-donating groups (push–pull system). As in the aminoquinolines described in the literature [14], the Schiff base derivatives present emission spectra in a different region to the amino derivatives (blue to green region), but with higher quantum fluorescence yields and Stokes shifts, a fact

• was studied in DMSO solution using a 1,3-diphenylisobenzofuran (DPBF) photooxidation assay and the adequate equation as described by Pivetta and co-workers [33]. In this study, the methylene blue dye (MB) was used as a reference. The photooxidation rate constants (k) and 1O2 yield of derivatives (ΦΔ

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• data on structure–activity relationship are still rare. First, we assessed the antiproliferative activity of the benzylisoquinolines 2a–f, 3a–c and 4 by CellTiter Blue cell viability assay and used tetrandrine as reference compound. In the cervical cancer cell line HeLa, none of the newly tested

• stimulated as indicated for 72 h. Two hours before termination, CellTiter Blue reagent (Promega) was added according to manufacturer’s instructions. Fluorescence intensity was measured at 590 nm on a Sunrise ELISA reader (TECAN) and is proportional to the cell number. Relative proliferation was calculated

• and B) VCR-R CEM cells. Cells were treated with the respective compound (50 µM) for 72 h and relative proliferation was assessed by CellTiter Blue assay. Statistical significance was determined by ordinary one-way ANOVA and Dunnett’s post test. *p < 0.05; ****p < 0.0001. C) Influence of

Adjusting the length of supramolecular polymer bottlebrushes by top-down approaches

• Tobias Klein,
• Franka V. Gruschwitz,
• Maren T. Kuchenbrod,
• Ivo Nischang,
• Stephanie Hoeppener and
• Johannes C. Brendel

Beilstein J. Org. Chem. 2021, 17, 2621–2628, doi:10.3762/bjoc.17.175

• s (blue), 10 s (magenta), 30 s (green), and 50 s (yellow) for BTU (A) and BTP (C). The injection peaks were omitted for clarity. cryoTEM images of BTU (B) and BTP (D) after 30 s of US exposure (c = 1 mg⋅mL−1). Supporting Information Supporting Information File 316: Synthesis, procedures, and

Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• . Under optimized conditions, the substrate scope was examined and determined to include activated olefins, unactivated olefins, and arylalkynes. In parallel, Hu and co-workers [51] reported the photoinduced, copper-catalyzed chlorosulfonylation of alkenes and alkynes under irradiation with blue LEDs

• proposed mechanism is shown in Scheme 15. Under blue visible light, the haloalkane is reduced by the copper acetylide to form the alkyl radical intermediate R2•. If aryl halide is the haloalkane, the copper acetylide is attacked by the aryl halide to form transition-state intermediate A. The copper

• (sp2)–H bonds of azoles was developed by Zhang [89]. A 2,2’-bipyridine copper coordination compound served as the photoredox catalyst and accomplished the azole C–H arylations. Under irradiation with blue LED, the photoexcited state [LnCuI-benzoxazole]* (C) engages in a double electron-transfer process

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• broad bands ranging from 365 to 500 nm (Figure 3). The emission spectrum of 4a appeared as a blue emission at 393 nm. Trifluoromethoxy derivative 4c exhibited a red shift of 10 nm as compared to 4a. Methoxy derivatives 4b and 4d showed similar emission bands at around 410 nm and gave larger red shifts

• giving an energy gap of 4.02 eV. The HOMO energy of derivative 4b was the highest and as a result it exhibited the lowest value of Egap and its electron conductivity was the best. The molecular electrostatic potential maps for tetrahydroacridines 4a–d are shown in Figure 10. The red and blue colors

• visualize the region of the attractive and repulsive potential, respectively. For the phenyl-substituted derivative 4a, the blue-colored surface, located mainly at the cyclohexane ring, visualizes the electron deficiency (high electrostatic potential). The red regions, localized essentially at the nitrogen

Targeting active site residues and structural anchoring positions in terpene synthases

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 2441–2449, doi:10.3762/bjoc.17.161

• incubation of GGPP with the SmTS1 A222V variant. Relative activities of SmTS1 and its variants towards GFPP (blue bars) and GGPP (yellow bars), and the production of compounds 8 (red bars) and 9 (grey bars). Wildtype activity towards GFPP was set to 100%. Means from triplicates, for standard deviations cf

• of cross peaks in blue and in red refers to the hydrogens in Scheme 1 of same colour. Determination of the enantiomeric composition of 8 and 9 obtained from GGPP with SmTS1 enzyme variants through enantioselective labelling with (R)- and (S)-(1-13C,1-2H)GGPP. Compound 8 is obtained with different

Synthesis and antimicrobial activity of 1H-1,2,3-triazole and carboxylate analogues of metronidazole

• Satya Kumar Avula,
• Syed Raza Shah,
• Khdija Al-Hosni,
• Muhammad U. Anwar,
• Rene Csuk,
• Biswanath Das and
• Ahmed Al-Harrasi

Beilstein J. Org. Chem. 2021, 17, 2377–2384, doi:10.3762/bjoc.17.154

• . Crystal structure of compound 3. Colour codes: carbon = grey, mitrogen = blue, oxygen = red, hydrogen = white. Crystal structure of 1H-1,2,3-triazole compound 5c: Colour codes: carbon = grey, nitrogen = blue, oxygen = red, fluorine = yellow, hydrogen = white. Crystal structures of compound 7b. Colour

• codes: carbon = grey, nitrogen = blue, oxygen = red, hydrogen = white. General structural feature of the synthesized molecules 5. The graph representing the antifungal activity of Didymella sp. against compounds 5a–i and 7a–e. The graph representing the antibacterial activity of E. coli against

A visible-light-induced, metal-free bis-arylation of 2,5-dichlorobenzoquinone

• Pieterjan Winant and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 2315–2320, doi:10.3762/bjoc.17.149

• on our findings. The authors reported the arylation of different substrates by irradiating aryldiazonium salts in methanol with blue light in the absence of a catalyst. Radicals are proclaimed to be generated through excitation of an intermediate aryl cation formed in the reaction. Eager to

• investigate the transferability of this concept to our system, the light source was changed to blue LEDs. This change seemed to increase reactivity, observed by significantly more vigorous nitrogen release, resulting in shortening of the reaction time to 2 h. The reaction yield on the other hand was slightly

• lower as compared to when green LEDs were used. Based on the report by Hashmi, we hypothesize that the overlap in wavelengths emitted by both green and blue LEDs cause the reaction to work in both instances. The diminished intensity of shorter wavelengths in the green LED causes a slower, more

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

• Janina-Miriam Noy,
• Fan Chen and
• Martina Stenzel

Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148

• nuclei of SW982 cells. The particles carry fluorescein (green), the mitochondria and lysosomes were stain with Mito and Lyso Tracker, respectively (red) and the nuclei was stained with Hoechst 33342 (blue). Merged images show co-localisation (yellow fluorescence). Cytotoxicity study of PPM-NP4-TPP and

(Phenylamino)pyrimidine-1,2,3-triazole derivatives as analogs of imatinib: searching for novel compounds against chronic myeloid leukemia

• Luiz Claudio Ferreira Pimentel,
• Lucas Villas Boas Hoelz,
• Henayle Fernandes Canzian,
• Frederico Silva Castelo Branco,
• Andressa Paula de Oliveira,
• Vinicius Rangel Campos,
• Floriano Paes Silva Júnior,
• Rafael Ferreira Dantas,
• Jackson Antônio Lamounier Camargos Resende,
• Anna Claudia Cunha,
• Nubia Boechat and
• Mônica Macedo Bastos

Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144

• , 2c, 2d, and 2g with the BCR-Abl-1 structure (PDB code: 3PYY), showing steric interactions (red dotted lines) and hydrogen bonds (blue dotted lines). Synthetic route of the triazole derivatives 1a,b, and 2a–j. Cytotoxic activity, confidence interval, and selectivity index of imatinib and derivatives

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• of aryl chlorides 8 through selective 2-functionalization of 1,3-dioxolane (13) followed by a mild acidic workup (Scheme 9) [61]. Here, the photocatalyst Ir[dF(CF3)ppy]2(dtbbpy)PF6 and nickel catalyst NiCl2·DME with dtbbpy as ligand, along with K3PO4 as base under irradiation with blue LEDs enabled

• perchlorate ([Acr-Mes]+ClO4−) [64]. The reaction was conveniently achieved at room temperature under blue light irradiation. Moreover, as shown in Scheme 13, electron-deficient aryl bromides were efficient in forming the desired products 23 in optimal yields. In contrast, only trace amounts of cross-coupled

• under irradiation of blue LEDs at ambient temperature afforded the desired α-arylation products 32 from secondary amides 31 and (hetero)aryl bromides 3 (Scheme 18) [72]. The method showed a broad substrate scope for both amides and aryl bromides. The authors also realized the enantioselective variant of

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• ). The striking feature of azulene is its permanent dipole moment (1.08 D) and blue color unlike its colorless isomer naphthalene [4]. Azulene possesses an unequal distribution of electron density between its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO

• backbone, resulting in the blue shift of absorption bands (λmax around 350 nm). Interestingly, the ethynyl linker in 17 was assisting the effective delocalization despite the presence of the n-alkyl group at position 6, as evidenced by its large red-shifted absorption at 456 nm compared to 19. The

• resonance signals when compared to free azulenes. The absorption and electrochemical studies conducted on these complexes 40–43 revealed that their properties could be tuned by varying the ruthenium content in the polymer. A higher ruthenium content was inducing a larger blue-shift of the absorption bands

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• dried pristine PCL scaffold. An explanation for this observation might be PHEMA´s ability to absorb water as well as the relative indistinct hydration state of PCL compared to PHEMA when fully hydrated. Toluidine blue staining was used as a rapid, colorimetric readout as it selectively binds to PHEMA

• min (Figure 1E) and the intensity of the blue coloration is proportional to reaction time resulting in a complete coating of the PCL fibers after 30 min. The distance between the UV source and the scaffold was varied from 0.5 cm, 1.0 cm, and 1.5 cm (Figure 1F) and, as the intensity decreases inversely

• ), however, this morphology is highly irregular. A change in wetting behavior could be demonstrated, and toluidine blue staining indicates successful SIPGP of HEMA on PCL scaffolds. However, to prove that this material is indeed PHEMA, we performed confocal Raman microscopy on the samples, which allows a

Enantioenriched α-substituted glutamates/pyroglutamates via enantioselective cyclopropenimine-catalyzed Michael addition of amino ester imines

• Zara M. Seibel,
• Jeffrey S. Bandar and
• Tristan H. Lambert

Beilstein J. Org. Chem. 2021, 17, 2077–2084, doi:10.3762/bjoc.17.134

• carbon, either in a concerted fashion or via subsequent addition of a putative acrylate enolate intermediate, would lead to the cycloaddition byproduct 11 (path b, red and blue dashed lines). It should be noted that cyclopropenimine catalysts do not promote the cyclization of 10 to 11. From this model

Towards new NIR dyes for free radical photopolymerization processes

• Haifaa Mokbel,
• Guillaume Noirbent,
• Didier Gigmes,
• Frédéric Dumur and
• Jacques Lalevée

Beilstein J. Org. Chem. 2021, 17, 2067–2076, doi:10.3762/bjoc.17.133

• conversions. To prevent the use of harmful UV light, different longer-wavelength photoinitiating systems (PISs) were proposed, e.g., blue light in dental materials [1][2]. Many PISs were developed for visible light, but much less studies are focused on the polymerization using near-Infrared (NIR) sources [3

Recent advances in the syntheses of anthracene derivatives

• Giovanni S. Baviera and
• Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

• application of several organic materials, such as organic light-emitting diodes (OLEDs) [5], organic field-effect transistors (OFETs) [6], polymeric materials [7], and other kinds of materials [8][9][10]. For example, OLEDs fabricated with 9,10-diphenylanthracene derivatives 1 and 2 are blue light emitters

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

• Ryan M. Alam and
• John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

• correlation between the C-7a (blue circle) or C-3 (red circle) atom of the indazole ring and the N-n-pentyl CH2 proton pair proximal to N atoms of the indazole nucleus, using (1H–13C) HMBC NMR experiments, permitted the regiochemical assignment of N-1 and N-2 substituted regioisomers 10 and 11, respectively

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• and B) [145]. The authors successfully applied a manganese salt in catalytic amounts, allied with the use of an electrical current in combination with blue LED lights and an organic photocatalyst (DDQ), affording azidated alkyl moieties in excellent yields and chemoselectivity through alkyl C–H bonds

Cationic oligonucleotide derivatives and conjugates: A favorable approach for enhanced DNA and RNA targeting oligonucleotides

• Mathias B. Danielsen and
• Jesper Wengel

Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125

• circles represent unmodified DNA monomers; blue circles represent nucleotide modifications. The gapmer-ASO shown is an example of a so-called 4-8-4 gapmer. The patterns of modified and unmodified nucleotides may vary and only examples are shown. Also, the phosphodiester linkages between the nucleotide