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

Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation

• Julian Spils,
• Thomas Wirth and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 27–32, doi:10.3762/bjoc.19.2

• decomposition of the intermediary iodoarene. Here it was possible to perform the procedure with either benzene or toluene, leading to a moderate yield of 38% and 37%. We could not use derivatives with any other substituents with secondary benzyl acetates since those led only to inseparable product mixtures

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

• oxidative decomposition to the core of 194 and 195. FGI followed to complete targets 196–200 (Scheme 16). Pyrroloindoline natural products (Knowles 2018) [102]: In 2018, Knowles’ group demonstrated the ability of TEMPO to act as a trap for radical cations arising from the single-electron oxidation of

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• by the respective DSC curves (Figures S15–S18 in Supporting Information File 1) and dTGA curves (Figures S19–S22 in Supporting Information File 1). Other thermal events such as minor phase transitions were observed for β-CD·BES and β-CD·PRO as well as premature decomposition, displayed by β-CD·BES in

• particular (Table 1). Thus, all CD complexes displayed thermal integrity until relatively high temperatures of at least 100 °C, prior to phase transitions and decomposition, indicating acceptable thermal stability for commercial pharmaceutical applications. Further analytical details regarding the TGA, dTGA

• K·min−1 until decomposition. The HSM experiment was viewed through a Nikon SMZ-10 stereoscopic microscope fitted with a Linkam THM600 hot stage and a Linkam TP92 temperature control unit. The images were captured by a real-time Sony Digital Hyper HAD colour video at selected temperatures. The captured

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• organic co-solvent), and slow decomposition occurred under acidic conditions at elevated temperatures. Alternative methods to cleave the benzamide using sodium peroxide [11] or triethyloxonium tetrafluoroborate [12] were also unsuccessful, giving either no reaction or significant decomposition

• silica gel resulted in extensive decomposition. Therefore, the crude imine was immediately hydrolyzed using aqueous citric acid [14], affording (−)-7-amino-7,8-dihydrobisabolene (4) as a single stereoisomer in 90% yield over the two steps. The enantiomer of 4 is itself a natural product with cytotoxic

Oxa-Michael-initiated cascade reactions of levoglucosenone

• Julian Klepp,
• Thomas Bousfield,
• Hugh Cummins,
• Sarah V. A.-M. Legendre,
• Jason E. Camp and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

• from 12 gave moderate to low yields of bridged species, most effectively with electron-poor aromatic aldehydes, and reactions had to be monitored to optimize conversions and prevent decomposition (Scheme 2) [14]. Analysis of the NMR spectra indicated that instead of the open chain diketones 13, the

Synthesis of meso-pyrrole-substituted corroles by condensation of 1,9-diformyldipyrromethanes with pyrrole

• Baris Temelli and
• Pinar Kapci

Beilstein J. Org. Chem. 2022, 18, 1403–1409, doi:10.3762/bjoc.18.145

•  1, entries 9 and 10). This situation can be explained by the instability of the bilane intermediate formed in the reaction medium and its decomposition during long reaction times. It was also investigated whether the product yield would increase with the amount of catalyst since only the copper

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• the cyclic hemiacetal 9 in modest yield (Scheme 2). Therefore, compound 8 was protected as silyl or benzyl ether using standard techniques. Unfortunately, no hydrolysis under several basic conditions provides the target ketone, no conversion and/or decomposition being observed (Scheme 3). Enol

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• –97%). This method allows for easy recovery of the unreacted aldehyde as well as separation of the product (just by extraction by hexane and drying under reduced pressure) without its decomposition. The structure of the final imines was confirmed by 1H NMR, 13C NMR, ESI–MS, and the release of the VOCs

• bond decomposition that Shiff base hydrolysis is very fast in acidic conditions and slows down when going to higher pH values. Multiple headspace extraction experiments revealed the role of pH and the presence of supramolecular interaction between aldehyde and β-CD on the rate of aldehyde release from

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization

• Sebastien Curpanen,
• Per Reichert,
• Gabriele Lupidi,
• Giovanni Poli,
• Julie Oble and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131

• under the same reaction conditions led predominantly to decomposition products and only 5-methylfurfural (resulting from protodesilylation) was recovered in low yield (≈20%). Hence, intramolecular hydroxy activation seems decisive to obtain productive cross-coupling reactions with this system. Also, it

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• diethyl ether at 0 °C for 1 h gave acid 10aa in 75% yield, while complete decomposition was observed at reflux temperature after only 10 min (Table 1, entries 1 and 2). Acid 10aa did not form when the reaction was performed in ethanol, CH2Cl2, THF, DMF, or ethyl acetate at different temperatures under

• formed in 50% yield in ethanol and 30% in diethyl ether (Table 1, entries 10 and 11). Reactions with thiol 8c, having an electron-donating methoxy group, and acid 9a or esters 9b,c only gave unidentifiable decomposition products in various solvents (ethanol, diethyl ether, methanol, and CH2Cl2) at

• (see Supporting Information File 1 for detailed reaction conditions) since decomposition of the benzothiazine core was observed in all coupling reactions. To avoid the issues related to the instable benzothiazine ring, we explored other possible linear reaction routes (Scheme 4) as an alternative to

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

• , entry 2). On the other hand, the isolated yield of 3 was decreased by the addition of H2O (Table 2, entries 3 and 4). This is probably because the addition of H2O promoted the generation of hydroxyl radicals, and a decomposition reaction became dominant. These results indicated that the oxygen source is

Isolation and biosynthesis of daturamycins from Streptomyces sp. KIB-H1544

• Yin Chen,
• Jinqiu Ren,
• Ruimin Yang,
• Jie Li,
• Sheng-Xiong Huang and
• Yijun Yan

Beilstein J. Org. Chem. 2022, 18, 1009–1016, doi:10.3762/bjoc.18.101

• . Diarylcyclopentenones, characteristic constituents of mushrooms [23], were rarely discovered in Streptomyces species. These components exhibit redox activity and are involved in reducing ferric (Fe3+) in the Fenton-based biological decomposition of lignocellulose [24][25]. The biosynthetic pathway of p-terphenyl was

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• . Moreover, when using an excess of a strong base, a low temperature would favor the occurrence of the iminoimide 7 whereas at a higher temperature, decomposition and the cyclization process giving isomer 4 would prevail. Conclusion This report describes some of the reaction parameters which orient and