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

• . Cook et al. [85] presented the first report of volumetric additive manufacturing-printed thiol–ene resins and showed the potential of the thiol–ene system. In addition to thiol–ene chemistry, radical hydrosilylation was also used to prepare linear, branched, or cross-linked polymers via a step-growth

Linker, loading, and reaction scale influence automated glycan assembly

• Marlene C. S. Dal Colle,
• Manuel G. Ricardo,
• Nives Hribernik,
• José Danglad-Flores,
• Peter H. Seeberger and
• Martina Delbianco

Beilstein J. Org. Chem. 2023, 19, 1015–1020, doi:10.3762/bjoc.19.77

• mostly performed on cross-linked polystyrene resins equipped with photocleavable linkers [3], offering orthogonality to all the synthetic steps of the assembly, while selectively releasing the glycan at the end of the synthesis. In recent years, the implementation of new synthetic strategies [4][5][6][7

• cleavage is probably influenced by glycan structure, solubility, and aggregation tendency [26]. Lastly, purification of the protected glycan upon cleavage could be affected by the presence or absence of a linker. L1 or L2 were conjugated to Merrifield resins with initial loadings of 0.5 mmol/g and 1.0 mmol

• -1,6-linked dimannosides 1 and 2 (Figure 2A) were successful on all resins tested, affording the desired product in complete purity regardless of linker type, loading or reaction scale (Figure 3A, and Figures S2 and S3 in Supporting Information File 1). Isolated yields of 49–59% were obtained in all

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

• reason for the low yield of compound 1 was eventually understood after it was determined to be a monoacylglycerol, which has a surface-active property and should have deteriorated the separation capacity of the chromatographic resins. The molecular formula of compound 1 was established to be C19H34O4

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• heterogeneous fashion. This oftentimes leads to improved green credentials, safety, and sometimes efficiency, especially when it is applied to the downstream process. Commercially available resins, activated charcoal, polymer-supported species that trap spent reagents or side-products as well as related

• /catalyst/byproduct to telescope several reactions before performing the final purification step offline (Scheme 8) [80][81][82][83]. Notable applications of metal scavengers such as QuadraPure® resins involve the removal of leached metals as well as catalytic amounts of homogeneous metal catalysts as

• ). In another case, the authors opt to use stoichiometric quantities of reagents to avoid the use of cartridges, even if the performance is worse, to reduce cost and time [93]. Catch and release strategy An interesting approach regarding the use of resins is their application in catch and release

Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes

• Mana Kitano,
• Tsuyoshi Saitoh,
• Shigeru Nishiyama,
• Yasuaki Einaga and
• Takashi Yamamoto

Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119

• -doped diamond electrode; electrosynthesis; oxidation; Introduction Selective oxidation of aromatic alkyl side chains is an important molecular transformation process to obtain various rubbers, resins, fine chemicals, and other industrial products [1][2]: terephthalic acid from p-xylene, cumene

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• such as the Egyptian around 5000 BC where resins of incense, opoponax, and myrrh were burnt for religious purposes [1]. Today, “the art of perfumery is closely connected to [synthetic] chemistry“, as outlined by Jean-Claude Ellena, the former master perfumer of Hermès [2]. In fact, the development of

• before the aldol condensation is initiated at 240 °C. While at lower temperatures, the aldol condensation proceeded incompletely, increasing the temperature to 250 °C lead to clogging of the reactor probably due to formation of phenolic resins as byproducts. In contrast, when the reaction is performed at

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

• (60–70%) [119]. By using ion-exchange resins such as Amberlyst® A26 (OH form) as a heterogeneous base in a fixed-bed reactor, the α,β-unsaturated compound 80 was obtained and with a stable performance over more than 15 hours of continuous operation (Scheme 14). In 2019, the group of Kobayashi

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• production of biodiesel [5][80], intermediates for triazine synthesis [48], etc. Some derivatives were grafted onto polystyrene resins for catalytic uses [5]. Various solvents and temperatures were used such as hot DMF [5], neat [79], toluene or hexane at 25–100 °C [79]. Generally, higher temperatures seem

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

• role of butoxide was postulated to be the activation of the heterogeneous splitting of dihydrogen. BDM is an important building block for the production of resins and polyesters other than PET [186][187]. Analogously, a similar Milstein-type ruthenium–PNN complex, generated in situ by treatment of the

• , polyurethanes, polyisocyanurates and resins [43]. Among the various glycols, EG is the most popular, resulting in the formation of BHET, formally through a (reversible) transesterification reaction (Scheme 5) [198]. Drawbacks of this method are the difficulty of purification of BHET, the need of an excess of EG

Coupling biocatalysis with high-energy flow reactions for the synthesis of carbamates and β-amino acid derivatives

• Alexander Leslie,
• Thomas S. Moody,
• Megan Smyth,
• Scott Wharry and
• Marcus Baumann

Beilstein J. Org. Chem. 2021, 17, 379–384, doi:10.3762/bjoc.17.33

• equiv) resins packed into an Omnifit glass column (10 cm length, 10 mm i.d., rt). This approach facilitated the removal of triethylamine, residual acid substrate, and diphenylphosphonic acid (generated from DPPA) and rendered a solution of the carbamate product containing only unreacted benzyl alcohol

Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes

• Dmitrii A. Aksenov,
• Nikolai A. Arutiunov,
• Vladimir V. Maliuga,
• Alexander V. Aksenov and
• Michael Rubin

Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239

• , the yield of 16a improved to 62% (Table 1, entry 8), while at 160 °C, it reached 77% (Table 1, entry 9). It should be pointed out that the reported yield of 77% is the isolated yield given complete conversion, with no detected side products aside from easily removable polymeric resins. With optimized

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 GSP-7, Moscow B-437, Russian Federation 10.3762/bjoc.16.212 Abstract In the present work, we suggested anion exchange resins in the phosphate form as a source of phosphate, one of the

• were tested in the synthesis of nelarabine, kinetin riboside, and cladribine with good to excellent yields (52–93%). Keywords: anion exchange resins; N6-benzyladenosine; cladribine; enzymatic glycosylation; kinetin riboside; nelarabine; α-ᴅ-pentofuranose-1-phosphates; phosphorolysis of nucleosides

• MeCN; 99.0% purity according to HPLC; for NMR data, see Supporting Information File 1, SI-1, SI-2 and SI-4). The capacity of the anion exchange resins to bind PF-1Pi As noted above, when studying Ara-U phosphorolysis catalyzed by E. coli UP in the presence of Dowex-nPi, we found that (1) about 10% of

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• obtained for AuNPs-SILLPs indicated that for the macroporous resins the NP size decreased when the size of the aliphatic residue of the imidazolium units increased with decyl N-substitution leading to smaller particle sizes [39]. The analysis of the polymeric samples revealed similar trends for the case of

Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies

• Giovanni Picca,
• Markus Probst,
• Simon M. Langenegger,
• Oleg Khorev,
• Peter Bütikofer,
• Anant K. Menon and
• Robert Häner

Beilstein J. Org. Chem. 2020, 16, 1732–1739, doi:10.3762/bjoc.16.145

• moiety for photocrosslinking to MPD-recognizing proteins. The presence of an additional propargyl group provides a way to further derivatize the probe with biotin azide via click-type chemistry [16] for the isolation of protein–lipid adducts using streptavidin resins [10]. To synthesize such molecular

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• -isosorbide) terephthalate, can replace polyethylene terephthalate (PET) [7]. In the production of polycarbonate and epoxy resins, the physicochemical properties of isosorbide allow the replacement of bisphenol A by this bio-based molecule [8][9]. At an industrial level, isosorbide is produced from the double

• Solid acid catalysts such as ion exchange resins exhibiting sulfonic groups on their external surface resembling to some extent p-toluenesulfonic acid (p-TSA) can be used in combination with supported metal catalyst (Scheme 6). Yamaguchi et al. used a combination of Ru/C and Pt/C with Amberlyst 70, an

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

• still trapped in the resins after the extraction, which led to a dramatic loss in photosensitisation efficiency over multiple recycles as it was progressively washed out. The flow-purified resins displayed no loss of efficiency over the recycles, indicating the flow purification had effectively removed

• the homogeneous photocatalyst. The flow synthesis also prevented the formation of a chlorinated byproduct identified on the batch resins as an intermediate, and purification could be applied to wash out reactants from the first step of the one-pot synthesis, a potentially useful synthetic advantage of

• postsynthetic modifications in flow [63]. Poliakoff, George, and co-workers reported a porphyrin photosensitiser ionically immobilised to sulphonate-cross-linked ion exchange polystyrene resins (amberlyst-15) for the synthesis of artemisinin (49). This resulted in a bifunctional material, which acts as a HPCat

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• of years dating back well before biblical times [2][3]. Plants and resins served as source for perfumes after alcoholic extraction. These extracts were not only used as fragrances but also as medicine (aqua mirabilis), aphrodisiac and elixir of life (aquavitae). In 1882 'Fougere Royale' was created

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• in the high-ionic-strength aqueous buffer required for native G4 structures was insufficient. In these cases, ion exchange to bromide (1b, 1ð, 1u, 6a, 7b, 7n) or chloride (1d, 1k–1q, 1t, 1w, 7ð, as well as 8a–12a and 14a–16a) was performed using ion-exchange resins (cf. Supporting Information File 1

Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• ) and the low content required. All these works on PC pave the way for highly reactive photosensitive systems that can be used for high tech applications: functional coatings, smart materials, new 3D printing resins, preparation of composites. Other development of PC can be expected in near future

Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

• Jacqueline Pollini,
• Valentina Bragoni and
• Lukas J. Gooßen

Beilstein J. Org. Chem. 2018, 14, 2737–2744, doi:10.3762/bjoc.14.252

• properties and industrial applications, for instance in surfactants, plasticizers, resins, soft materials and diverse medical applications [7]. Isolated via cold-press or solvent extraction processes, it contains predominantly anacardic acid (1). Upon distillation or any other thermal treatment, anacardic

• ][10]. These include aromatic amines as polymers [11][12], cardanol-based phosphates as modifiers for epoxy resins [13], cardanol grafted natural rubber as rubber plasticizers [14], amine-based surfactants [15] and phenol/cardanol-formaldehyde based adhesives [16]. The chemical valorization of

Novel solid-phase strategy for the synthesis of ligand-targeted fluorescent-labelled chelating peptide conjugates as a theranostic tool for cancer

• Sagnik Sengupta,
• Mena Asha Krishnan,
• Premansh Dudhe,
• Ramesh B. Reddy,
• Bishnubasu Giri,
• Sudeshna Chattopadhyay and
• Venkatesh Chelvam

Beilstein J. Org. Chem. 2018, 14, 2665–2679, doi:10.3762/bjoc.14.244

• differentially protected Fmoc-Lys-(Tfa)-OH plays a vital role in attaching fluorescent tags while growing the peptide chain in an uninterrupted manner. The methodology is versatile for solid-phase resins that are sensitive to mild and strong acidic conditions when acid-sensitive side chain amino protecting

• in commercial resins such as Universal Nova tag or hyperacid labile resins such as Rink acid [26], 4-hydroxymethylphenoxybutyryl (HMPB), chlorotrityl [27], SASRIN [28] and Sieber amide [29]. Even though such resins are very useful, they suffer from several disadvantages. For example, i) they are cost

• commonly available and less expensive cysteine-labelled 2-chlorotrityl resin (Figure 1b). The methodology is general and can be significantly useful for acid-sensitive resins that contain acid-labile orthogonal amino acids with 4-methoxytrityl (Mmt) and 4-methyltrityl (Mtt) protecting groups. Results and

Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

• Bimal Koirala,
• Robert A. Hillman,
• Erin K. Tiwold,
• Michael A. Bertucci and
• Yftah Tal-Gan

Beilstein J. Org. Chem. 2018, 14, 1769–1777, doi:10.3762/bjoc.14.151

• reagents and instrumentation. All chemical reagents and solvents were purchased from Sigma-Aldrich and used without further purification. Water (18 MΩ) was purified using a Millipore Analyzer Feed System. Solid-phase resins were purchased from Chem-Impex or P3 Biosystems. Reversed-phase high-performance

Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis

• Dan Liu,
• Ya-Li Guo,
• Jin Qu and
• Chi Zhang

Beilstein J. Org. Chem. 2018, 14, 1112–1119, doi:10.3762/bjoc.14.97

• equiv of Fmoc-protected amino acids, 3.0 equiv of FPID, 3.0 equiv of (4-MeOC6H4)3P and 3.0 equiv of TEA in DMF. After chain elongation and deprotection of Fmoc, the resulting resins were treated with 0.5% TFA/DCM to give the N,C-unprotected peptides as final products. The peptides were purified by

Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions

• Kendra Leahy Denlinger,
• Lianna Ortiz-Trankina,
• Preston Carr,
• Kingsley Benson,
• Daniel C. Waddell and
• James Mack

Beilstein J. Org. Chem. 2018, 14, 688–696, doi:10.3762/bjoc.14.57

• the ones obtained under traditional solution-based conditions. First, we observed that using functionalized resins allowed us to isolate the desired product in an easy and environmentally benign manner. Second, we observed that the incorporation of liquid-assisted grinding (LAG) increased the rate of

Synthetic mRNA capping

• Fabian Muttach,
• Nils Muthmann and
• Andrea Rentmeister

Beilstein J. Org. Chem. 2017, 13, 2819–2832, doi:10.3762/bjoc.13.274

• translational activity in an in vitro translation assay. Besides their use in the preparation of cap-modified RNAs via IVT, cap analogues have found alternative applications. Since cap-binding proteins (e.g., eIF4E and DcpS) have high affinity to cap analogues, resins functionalized with the cap analogue m7GTP

• can be used to purify binding proteins from fractionated cell lysates [74][75][76]. Using m7G-modified sepharose resins, novel cap-binding proteins such as gemin-5 could be identified [77]. The affinity resins can be stabilized via methylene moieties, preventing enzymatic degradation of the cap