Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• )-1,1,1,4,4,4-hexafluorobut-2-ene (1a) under UV irradiation leads to the formation of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2) [1]. Subsequent dehydrobromination of compound 2 by treatment with alcoholic potassium hydroxide formed a mixture of isomers 2-bromo-1,1,1,4,4,4-hexafluorobut-2-ene (3a,b) with a

• bromine in the same manner under the influence of ultraviolet irradiation or sunlight with the formation of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2) in 95% yield (Scheme 1). The only difference was that under UV irradiation, the reaction proceeded faster. In both cases, product 2 represented a mixture

• presence of SbCl5, AlCl3, Bu4NOH/MeOH and under UV irradiation. We found that under UV irradiation for several hours, the (E)-isomer 3a completely transformed into (Z)-isomer 3b in quantitative yield (Scheme 3). Next, our attention was directed toward the reaction of (E)- and (Z)-butenes 1a,b with iodine

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• derivatives can penetrate cells and interact with A-domains in live bacterial cells, resulting in the competitive inhibition of the labeling by ʟ-Phe-AMS-BPyne. The substituent group (R; gray) of ʟ-Phe-AMS derivatives could facilitate their cell penetration. After UV irradiation (365 nm), the labeled proteins

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• photosensitizer in an energy-transfer (EnT) mechanism. This proposal was supported by fluorescence quenching measurements, as well as the direct excitation of 44 by UV irradiation, resulting in the formation of 45 in a 45% yield. According to this hypothesis, NHPI ester 44 would adopt a favorable conformation (46

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• potentials of the halides that can be reduced in this way, quantum-chemical calculations, and steady-state and transient absorption spectroscopy suggest that UV irradiation accelerates the reactions via cleavage of the dimers to the corresponding radical monomers. Keywords: dehalogenation; n-dopant

• example, see ref. [32]), and were synthesized as described in Supporting Information File 1. More complete data are shown in Supporting Information File 1, Tables S1 and S2. As in the case of 1a, conversions and yields under UV irradiation in the absence of reductant are low on a 2 h timescale (≤10%) and

• the main products are those in which the halide is replaced by a hydrogen atom. The more easily reduced benzyl halides examined (1b and 1c) are dehalogenated by (N-DMBI)2 in the dark, and with (N-DMBI)2 and UV irradiation are quantitatively dehalogenated in 2–6 h with the corresponding substituted

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• and visualized by UV irradiation at 254 nm. Preparative column chromatography was carried out using silica gel 60 (0.040–0.063 mm) from Merck. The NMR spectra were recorded on Bruker Avance 400 MHz or Bruker Avance 600 MHz spectrometers. Chemical shifts (δ) are reported in parts per million (ppm

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• UV irradiation without a photoinitiator [176][177]. Grafted polymers and untethered polymers are generated simultaneously in the presence of a monomer. Ionizing radiation including high-energy photons (X-rays and γ-rays) and charged α- or β-particles generate charged particles, especially electrons

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• two directions resulting in the formation of a mixture of the corresponding dihydrobenzo[h]pyrano[2,3-f]quinazolines and polyaromatic products. The obtained dihydro derivatives are stable compounds and do not undergo aromatization upon further UV irradiation. The structures of two of the dihydrobenzo

• ]. Among them, photoreactions of compounds containing the 3-hydroxypyran-4-one (allomaltol) fragment attract considerable attention due to the unique photochemical properties of compounds of this class. Previously it was shown that allomaltol derivatives under UV irradiation undergo contraction of the

• investigated. It should be noted that we have previously studied the photochemical properties of various terarylenes with a 3-hydroxy-4-pyranone moiety [21][22][23][24][25]. It was shown that UV irradiation of such systems leads to a complex mixture of products, apparently due to the simultaneous occurrence of

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• powders of CS-TPE exhibit a pale-yellow appearance under normal daylight conditions and emit intense green-blue light when exposed to UV irradiation (365 nm). This phenomenon differs greatly from the fluorescence properties of conventional ACQ fluorophores, which are typically nonfluorescent under UV

• spectra of TBTQ-C6/CS-TPE with different Rf in aqueous solutions at pH 5.3 and 10.4. Inset: the fluorescent images of the corresponding measured solutions taken under UV irradiation. ([TBTQ-C6] = 0.10 mM, [CS-TPE-2%] = 32 μg/mL), [CS-TPE-10%] = 34 μg/mL, [CS-TPE-20%] = 35 μg/mL, [TBTQ-C6/CS-TPE-2%] = 48

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• % yield (Table 1, entry 6). In addition, in a catalyst-free reaction under UV irradiation, no reaction occurred and the starting diazo compound 5 was recovered (Table 1, entry 7). Having identified the optimal catalyst and conditions, we then examined the scope of the cyclopropanation reaction by reacting

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

• ). Interestingly, the reaction was carried out under UV irradiation and in the presence of catalytic nickel diiodide allowing formation of the expected compound in 63% yield [67]. 4.2 SmI2-mediated ketyl addition: discussion around pleuromutilin scaffold access Despite the promising results of the SmI2-mediated

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• substantial decrease of the product yield. FGI, followed by methylenation provided the common scaffold 88. Further elaboration of 88 to natural products 90 and 89 was accomplished by UV irradiation at 365 nm in MeOH and by utilizing singlet oxygen (using rose Bengal) in MeCN/pyridine, 40:1, respectively

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• host against oxidative radicals generated by UV irradiation [25][32]. To verify the antioxidative effect of the isoflavone dimers, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)-based antioxidant activity was performed [33]. The results showed that while 2 and 3 had an activity roughly

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

• -induced processes are of considerable interest in the context of green chemistry [8][9]. At the same time in some cases UV irradiation of organic compounds leads to the formation of highly reactive intermediates. Such objects may, possessing a specific reactivity, which define their further application in

• of photoreactions can occur under UV irradiation: the classical photocyclization of the 1,3,5-hexatriene system and excited state intramolecular proton transfer (ESIPT) – promoted photoprocesses typical for a 3-hydroxypyran-4-one core. For the ESIPT-induced reactions the general direction is the

• processes can be complicated if additional photosensitive fragments are presented in the structure. For example, we previously studied the photochemical behavior of oxazolone terarylenes 9 containing the allomaltol fragment (Scheme 1C) [26]. It has been shown that UV irradiation of such systems leads to a

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• ) and compounds were visualised by UV irradiation (λ = 254 nm) and/or dipping in ethanol/sulfuric acid (95:5 v/v) followed by heating. A Biotage SP4 flash chromatography system was used for purification of the protected sugars with normal phase silica (pre-packed SNAP Ultra cartridges). Deprotected

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• synthesis of trisphaeridine to afford the product in four linear steps in an overall yield of 6.5% from 1-bromo-2,4,5-trimethoxybenzene. Keywords: aromatic compounds; cyclization; iminyl radical; phenanthridines; radical cation; synthesis; UV irradiation; Introduction Phenanthridine derivatives have

• reported by Rodrıguez and Walton we envisaged that under these photochemcial conditions, intermediate 8 would be formed. Contrary to the expected results, in our labs exposure of oxime 7 to UV irradiation yielded phenanthridine 9 as the main product alongside the nitrile 10 in lower yields [13]. We

• hydrochloride and then acetyl chloride afforded oxime 22. Next was the key photochemical step. Exposure of 22 to UV irradiation resulted in the formation of the desired phenanthridine 23 in a disappointing yield of 41%, together with the benzonitrile 24. Phenanthridine 23 was then treated with CAN followed by

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• the products that absorbed UV light were detected by UV irradiation. The melting points were measured using a Yanaco MP-S3 apparatus and are uncorrected. IR spectra were recorded on a Perkin–Elmer Frontier FTIR in the ATR mode. NMR spectra were recorded in CDCl3 solutions using a JEOL JNM-LA 300, JEOL

Manganese/bipyridine-catalyzed non-directed C(sp³)–H bromination using NBS and TMSN₃

• Kumar Sneh,
• Takeru Torigoe and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

• radical C(sp3)−H halogenation at the benzylic and allylic position using N-halosuccinimide with azobisisobutyronitrile or benzoyl peroxide as a radical initiator is known as the Wohl–Ziegler bromination reaction, which requires heating, acidic/basic conditions, and/or UV irradiation (Scheme 1a) [17][18

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• ethereal solution of diazomethane in toluene at 0 °C resulted in pyrazoline derivative C [81]. The adduct isolated chromatographically was exposed to ultraviolet (UV) irradiation for 25 min at 25 °C in a quartz tube. The resulting isomers 3 and 4 were separated by reversed-phase high-performance liquid

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• crystallinity, reduced chain mobility and hydrophobicity of polymers [114][115], which makes biodegradation often ineffective and time-consuming, particularly for polyolefins, such as polyethylene, polyvinyl chloride (PVC), polystyrene or PET [116][117]. Thus, abiotic pretreatments may be required, including UV

• irradiation [118], oxidation [119] or acidic degradation [120]. It is worth mentioning that organocatalytic depolymerisation methods have also been reported [121][122]. Despite these systems represent promising “greener” options, they still are in an early development stage. Uses are mainly limited to

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32