Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• complete decomposition. With the desired naphthylamines in hand, we were able to complete our synthesis of four chelerythrine variants as shown in Scheme 7. After N-formylation providing intermediates 11 and 12 in good yield, a three-step sequence was performed: Suzuki coupling of the aryl bromide with one

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• as σ-donor ligands only. However, subsequent experimental [18] and theoretical [19] studies revealed that a simultaneous back donation from the d-orbital of the metal to the π*-orbital of the NHC occurs in these species, which was also corroborated by energy decomposition analysis (EDA) calculations

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• protective gas atmosphere, leads to slow decomposition. Therefore, storage at low temperature in a dark vial is strongly recommended. Upon using 2,4-dibromoaniline (1c) as the substrate and an excess of phenylacetylene (2a), both carbon–bromine bonds are transformed in the alkynylation step affording the

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• identical molecular peak ion and C, H, N values within acceptable deviation of 0.4%. The decomposition temperature (Td, corresponds to 5% weight loss) was measured by thermogravimetric analysis (TGA) indicating excellent thermal stability for 4BGIPN with Td = 425 °C, which is similar to the benchmark

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• pathway. Initially, a tert-butoxyl radical is generated by thermal decomposition. Then, the tert-butoxyl radical extracts an α-hydrogen atom from tetrahydrofuran to form tetrahydrofuran radical A. Sc(OTf)3 as a Lewis acid activates pyridine forming the pyridine complex B. Then, radical A adds to the more

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

• decomposition [1][102]. They discovered that an iodonium ylide (e.g., 6/I-12) reacts with hydrochloric acid to produce a chlorinated β-dicarbonyl 7, opposite their expectation that the C–I bond with the lower electron density would be cleaved. While both of these reaction pathways are viable, the iodonium ylide

• produced in 74% yield after six days at room temperature in the absence of catalyst (Scheme 2a) [107]. At that time, the authors did not articulate any theory as to how the reaction might initiate under such mild conditions, though they recognized that the decomposition of 8 into a free carbene would not

• and Liang modified the iodonium ylide’s β-dicarbonyl skeleton (Scheme 11), and while derivatives of barbituric acid (54a) and Meldrum’s acid (54b) were moderately effective, replacing the gem-dimethyl with spirocyclic motifs 54c–e provided [18F]fluorobiphenyl 55 in 47–85% yield [134]. Decomposition

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

• , or it is trapped with pyrrole derivatives 3 in a C–C bond formation to afford arylated products 4. Based on the ultrashort lifetime of *PDI•− (τ = 145 ps), the notion of its photochemistry has attracted skepticism and it has been suggested decomposition products of *PDI•− may instead serve as

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• with excess hydrochloric acid and further evaporation of the solvent at 40 °C led to decomposition products, two of which were isolated and characterized by NMR spectroscopy including 2D experiments and HRMS data. The target acids 5k,m were obtained using equivalent amounts of HCl at room temperature

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• of TADF emitters is very important for the application in OLED devices. Therefore, the compounds were investigated by thermogravimetric analysis (TGA) and the results are shown in Figure 6 and Figure S34 in Supporting Information File 1. The thermal decomposition temperature (temperature at 5

• an approximate 3LE state. Thermogravimetric analysis (TGA) shows that the thermal decomposition temperature of these compounds is higher than 360 °C, and the thermal stability is excellent. From the above studies, TADF properties of such compounds can be studied with conventional spectroscopic

• components to be used for Global analysis was estimated by performing a preliminary singular values decomposition (SVD) analysis. All data were chirp-corrected before global fitting. Nanosecond transient absorption spectroscopy The nanosecond transient absorption spectra were measured on a LP920 laser flash

Synthesis of tetrahydrofuro[3,2-c]pyridines via Pictet–Spengler reaction

• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2023, 19, 991–997, doi:10.3762/bjoc.19.74

• -carbaldehyde (2p) was used. In this case, we observed abundant tarring and decomposition of the reaction mixture, which is probably due to the acidophobic nature of monosubstituted pyrroles. Surprisingly, the reaction of 4-(methylthio)benzaldehyde (2h) with 2-(5-methylfuran-2-yl)ethylamine (1a) under the

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• shown in Scheme 20b. In this mechanism, calcium nitrate first activates the decomposition process of 2,5-DMTHF (2) from A to B. Further, a nucleophilic attack of amines 42 on B generates imine intermediate C. Finally, intramolecular nucleophilic attack by enamine D on the aldehyde group, dehydration and

• of acid-sensitive pyrrole derivatives without decomposition in a short time. Abid et al. [89] described the synthesis of N-substituted pyrrole derivatives in good yields using K-10 montmorillonite as an effective solid acid catalyst under microwave irradiation. K-10 monomorillonite is a widely used

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• compounds were obtained; this result was probably due to the competitive cycloaddition and polymerization reactions and decomposition of the diene moiety, which is unstable and very sensitive to acidic and basic conditions [106]. As shown in Figure 3 and anticipated above, our proposed mechanism begins with

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO₂F₂)

• Xian-Lin Chen and
• Hua-Li Qin

Beilstein J. Org. Chem. 2023, 19, 901–908, doi:10.3762/bjoc.19.68

• ). Either increasing the temperature to 120 °C or decreasing to 80 °C resulted in an obviously decreased yield (Table 1, entries 13 and 14), which could probably be attributed to the decomposition of the highly active sulfonyl ester intermediate. The reaction time was also screened and the yield did not

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

• substituent may prevent the attack of other reagents and suppress the decomposition of the nitrocyclopropane framework. The chemical transformation of cyclopropane 1e was investigated. When a solution of 1e and tin(II) chloride in benzene was heated at 100 °C for 14 h, successive ring-opening/ring-closure

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• (9a) or decomposition (Scheme 3 and Table 1). Table 1 shows that in both polar aprotic solvents without base and thiophile (entries 1 and 4) only tricyclic 5,5-dimethyl-2-phenyl-4,5-dihydrothiazolo[4,5-c]isoquinoline (8a) was formed probably through unstable intermediate (7a). Compound 7a can be

• . The addition of a strong thiophile (Ph3P; Table 1, entry 5) does not turn the reaction toward the ECR, and only several other decomposition products can be detected together with 8a. Triethylamine causes the decomposition of salt 6a in both polar aprotic solvents (Table 1, entries 2 and 6). In MeCN

• desirable ECR product 9a in 62% or 55% yield (entries 3 and 7 in Table 1) together with other decomposition products from which only thiobenzamide and benzonitrile were identified. In pure trimethyl phosphite (Table 1, entry 8) that acts simultaneously as polar solvent and mild thiophile, the parallel

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

• of the photoproducts (Table 2). Based on the structure of compound 11a we assumed that it could be converted into a polyaromatic product using conventional synthetic methods. However, the use of different systems (TsOH/toluene, HCl/EtOH, DBU/EtOH, MeONa/MeOH) resulted only in the decomposition of 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

• determined for the enantiopure helicenes. For compound 12, the racemization barrier was 24.8 kcal mol−1 at 298 K, which provides a racemization half-life (t1/2) of 24.4 h. For compounds 11 and 13, neither racemization nor decomposition was observed by chiral HPLC after heating hexadecane solutions of each

• racemization barrier for [7]helicene, neither racemization nor decomposition was observed for optical pure 86 at 180 or 200 °C for 24 or 4 hours. Recently, they reported another HBC-trimer 91 consisting of only one tropone [55]. Dibromo 87 was converted into its corresponding distorted hept-HBC 88 by oxidative

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

• % yield, respectively. Compounds are stable in the refrigerator for more than six months; however, after one year partial decomposition of sample Phen-Py-2 was observed. Spectroscopic characterization of Phen-Py-1 and Phen-Py-2 in aqueous solution UV–vis spectra Studied compounds Phen-Py-1 and Phen-Py-2

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

• unsaturated fatty acid glycerides significantly decreases the stability of hazelnut oil. Only one study was performed on the γ-CD nanoencapsulation of hazelnut oil by a co-precipitation method and the thermal decomposition of the complex was evaluated by TG [34]. One way of enhancing the oxidative stability

Group 13 exchange and transborylation in catalysis

• Dominic R. Willcox and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

• transborylation in catalysis (Scheme 6) [69]. Reactive intermediates were characterised and BH3 was observed to be generated in situ by the decomposition of HBpin. The proposed catalytic cycle involved nucleophile-promoted decomposition of HBpin to various borohydride species 19, which reacted with the BH3

• , including LiAlH4, promoted the decomposition of HBpin to BH3 which can mediate hidden catalysis [56]. Thomas et al. reported the aluminium-catalysed hydroboration of alkenes, using HBpin and LiAlH4 as the catalyst (Scheme 20) [94]. Through single-turnover experiments they suggested a mechanism similar to

• aluminium-catalysed alkyne hydroboration; hydroalumination of the alkene 4 by the alane catalyst 80, Al‒C/B‒H exchange with HBpin, to give the alkylboronic ester 6 and regenerate the alane catalyst 80. A hydride-mediated decomposition of HBpin and hidden catalysis were not ruled out, as the use of LiH or

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• %. Unfortunately, the MeO-substituted derivative 5ad did not form. Except for the acetamide 5ae, which could not be obtained due to decomposition, other meta- and para-substituted derivatives 5af–ak, among them derivatives with strong electron-withdrawing functionalities, could be synthesized in 39–69% yield. The

• to iodide and bromide were performed giving the salts 10a and 10b in excellent yields [27]. A copper-catalyzed iodination gave the diiodinated product 11 in quantitative yield [42]. Finally, N-methylation of 5aa was performed, to yield the dicationic salt 5av in 56% yield without decomposition of the

Synthesis, α-mannosidase inhibition studies and molecular modeling of 1,4-imino-ᴅ-lyxitols and their C-5-altered N-arylalkyl derivatives

• Martin Kalník,
• Sergej Šesták,
• Juraj Kóňa,
• Maroš Bella and
• Monika Poláková

Beilstein J. Org. Chem. 2023, 19, 282–293, doi:10.3762/bjoc.19.24

• decomposition analysis (FMO-PIEDA). Results and Discussion Chemistry The target N-arylalkyl 1,4-imino-ᴅ-lyxitol derivatives modified at C-5 were synthesized by the analogous approach that we had reported previously for their ʟ-enantiomers [33]. First, the key, fully protected N-benzylpyrrolidine 3 was prepared

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

• Benedikt Kolb,
• Daniela Silva dos Santos,
• Sanja Krause,
• Anna Zens and
• Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

• enynes 25a–e in yields up to 77%. Unfortunately, in the case of nitro-substituted enyne 25d only 4% were isolated due to rapid decomposition and instability issues (Table 1, entry 4). With enynes 25a–e in hand, the influence of solvent, reaction temperature, time, and Pd source on the hydrozirconation

• substituents at the benzoyl moiety of 25. The analysis of crude 1H NMR spectra of 27 indicated decomposition and side product formation (for details see Supporting Information File 1, chapter 2.2). Unfortunately, due to the poor amount of side products, these compounds could not be isolated by chromatography

• and HPLC purification steps. However, GC–MS analysis of the crude product of one exemplary dienone 27ac (with only 17% yield) indicated only decomposition in the reaction sequence. Further, phenylenyne 25a was treated with different conjugated and aliphatic acyl chlorides 26m–p (Table 4, entries 13–16

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• benefits from the leaving group ligation at the latest stages of the cross coupling. This is particularly interesting since it can hamper the usual decomposition of the iron catalyst, which tends to afford unreactive reduced aggregates at the end of the catalytic transformation, when the coupling kinetics

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• (viz 106) was formed. In part, this was found to be due to decomposition (and self-condensation reactions) of the dimethylthio-substituted allyl alcohol 105. However, also the minor adducts that were formed with the olefins were shown to be mixtures of exclusively non-cyclic allylation products of the