Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• reaction (Table 1, entry 1) [4]. In the presence of potassium carbonate, only starting material 4a was detected. A stronger base to generate the nucleophilic intermediate was tested, and sulfonamide 5aa was detected in trace amounts (Table 1, entry 2). Considering the low solubility of the hypervalent

Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• conditions. We carried out the palladium-catalyzed intramolecular coupling reaction of precursor 1a under similar conditions [23], which afforded smooth reaction with phenanthroline bisamide, with 10 mol % of palladium acetate as a catalyst in the presence of potassium carbonate and tetra-n-butylammonium

• resulted in a decreased yield (27%) (Table 1, entries 4 and 5). It was found that increasing the amount of potassium carbonate to a three-fold excess improved the yield of 2a to 59% in the reaction at 110 °C shown in entry 6 of Table 1. Next, the effect of the ligand of the palladium catalyst was examined

• . Experimental Typical experimental procedure for the C–H arylation of pyridine derivative 5-octyldibenzo[b,f][1,7]naphthyridin-6(5H)-one (2a): To a screw-capped test tube equipped with a magnetic stirring bar were added amide 1a (44.1 mg, 0.100 mmol), potassium carbonate (42.0 mg, 0.304 mmol

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• functional groups for subsequent product diversification (Scheme 1). For example, protected alkynylboron reagents can be employed [35][36][37], such as N-methyliminodiacetic acid (MIDA)boronate esters [38], potassium trifluoroborates [39], and others [40][41][42]. Similarly, organosilicon reagents have

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• can be noticed that the presence of an amino acid is compatible with the conditions of the reaction and did not interfere or significantly decrease the yield of the reaction (Scheme 3). Then, the N-carboxylate hydrazides 5a–d were firstly oxidized with iodine in the presence of potassium carbonate to

• on an intramolecular Michael addition carried out in DMF and catalyzed by 10% of potassium carbonate. As previously observed [37], under these conditions, the 5-endo-trig cyclization was selective and the lactam resulting from the 5-exo-trig cyclization was not observed. Furthermore, in the case of

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• 4 (65%), 5 (50%), and 6 (40%) by chromatography was straightforward. However, the subsequent oxidation of the alcohol with the usual oxidizing agents (Jones reagent, KMnO4, etc.) was not successful. A radical oxidation with TEMPO, potassium bromide (KBr), sodium hypochlorite (NaOCl), and sodium

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• solution (10 mg mL−1 in CHCl3) of the semiconductor material was deposited by spin-coating at 1000 rpm for 60 seconds. Synthesis Compound 2a 16,17-Dihydroxyviolanthrone (500 mg, 1.02 mmol) and 2-ethylhexyl bromide (550 μL, 3.06 mmol) were dissolved in N,N-dimethylformamide (30 mL). Then, potassium

• mmol) and 1-bromooctane (2.12 mL, 12.28 mmol) were dissolved in N,N-dimethylformamide (60 mL). Then, potassium carbonate was added (1.13 g, 8.19 mmol), and the reaction mixture was stirred at 100 °C overnight. After cooling the reaction mixture to room temperature, it was poured into methanol (400 mL

• ]+ calcd for C50H48NaO4, 753.3409; found, 735.3445. Compound 2c 16,17-Dihydroxyviolanthrone (500 mg, 1.02 mmol) and 1-bromododecane (800 μL, 3.06 mmol) were dissolved in N,N-dimethylformamide (30 mL). Then, potassium carbonate was added (300 mg, 2.04 mmol), and the reaction mixture was stirred at 100 °C

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• solvent, whereas the arylation of ammonia was achieved by using ethyl acetate as solvent along with potassium carbonate as a base. Likewise, water was arylated using cesium carbonate as a base. The N-arylation reactions were performed under strict anhydrous conditions. The reported mechanistic hypothesis

• of O3-arylated galactosides 64 by reacting benzyl-protected galactoside 63 with diphenyliodonium triflates 16 at room temperature in the presence of potassium tert-butoxide as the base (Scheme 26) [77]. This transition-metal-free approach simplifies the synthesis process. Electron-pushing and

• 101 for the S-arylation of potassium O-alkyl xanthates 100 offers a simpler approach [95]. This method operates under mild conditions, facilitating the creation of substituted S-aryl xanthates 102 (Scheme 41). Utilizing diaryliodonium salts for the arylation of xanthate anions provides a pathway for

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• steps from indigo (1a). The reaction of 1a with potassium permanganate afforded product 12 which was transformed to dehydroindigo (13) by pyridine-mediated elimination of acetic acid. The reaction of 13 with tetra-O-trimethylsilyl-ʟ-rhamnopyranose (4b) in the presence of trimethylsilyl iodide, addition

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• (Table 3, entry 2). Indeed, using THF that had not been dried as purchased resulted in a significant increase of the yield to 82% (Table 3, entry 3). The choice of base was also crucial (Table 3, entries 3–5). While the yield of 5a was low with potassium tert-butoxide, a yield of 66% using lithium tert

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• shaken for 15 min and then placed in an oven at 100 °C until the silica gel was completely dried. The impregnated silica gel was stored in the dark until use. Syntheses 1-(1-Propen-1-yl)piperidine (2): In a manner analogous to [27], potassium carbonate (2 g, 15 mmol), piperidine (10 mL, 0.1 mol), and

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• -acylimidazoles with potassium alkenyl trifluoroborates under mild electrochemical conditions (Scheme 41). This method provides an efficient and enantioselective approach to C(sp3)–H alkenylation, demonstrating the potential of combining chiral catalysis with electrochemistry for the functionalization of complex

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• the magnesium and potassium glutamate concentration, is 140 mM, which is less than half the concentration reported for the cellular environment. The cytoplasmic osmolarity of about 600 mOsm [16] is 50% higher than that calculated for CFPS. Taking into account all defined components, the water content

• for the calculation of the macromolecular concentration of the CFPS mix. Magnesium and potassium glutamate were considered as the contributing inorganic ions for the reference composition, for the DES corresponding salts were added to the value of 140 mM. For the osmolarity the concentrations of all

• defined components were multiplied with their number of dissociated particles, which was assumed as 1 for most components and 2 for magnesium and potassium glutamate and combined with the calculated concentration of macromolecules. For the water content, the amount of all known components was subtracted

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• generated by altering the reaction conditions during synthesis [52][53][54][55][56][57] or by using potassium chloride or ammonium fluoride salts as additives [58][59][60]. In a comprehensive study [61], the catalytic properties of three types (rope, rod and fibre) of mesoporous silica Santa Barbara

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• give 1,5-diacyl-5-hydroxypyrazolines 131. Cleavage of the protecting group with potassium carbonate in methanol finally provides the corresponding 5-acyl NH-pyrazoles 132 (Scheme 46) [149]. A novel approach to synthesizing pyrazoles via the initial formation of isoxazoles 138 through (3 + 2

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• ) [43]. In parallel, Sheng and Zhang et al. found that 2-(1,3,4-oxadiazol-2-yl)aniline derivatives 38 could be electrochemically synthesized from isatins 35 and acylhydrazine 36. The transformation was carried out in an undivided cell at high temperature in DMSO using potassium iodide as supporting

• electrolyte with potassium carbonate as a base and two platinum electrodes. Mechanistically, condensation of the two reactants formed isatin-derived acylhydrazone 37. Hydrolysis of the latter in the presence of the inorganic base gave rise to potassium carboxylate 39. Meanwhile, two consecutive SET oxidations

• -triazoles was accomplished by D. Tang et al. through the formal cycloaddition between in situ-generated aldehyde-derived hydrazones and cyanoamine (70). The 5-amino derivatives 71 were obtained in moderate to good yields by employing potassium iodide as electrocatalyst (Scheme 13) [55]. Herein, the

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• -substituted indazole analogs in 44% and 40% yields, respectively, by treating compound 6 with methyl iodide and potassium carbonate in dimethylformamide (DMF) at room temperature for 17 h [40]. Other works have shown poor selectivity when 6 and other isomers similar to 6 were reacted with isopropyl iodide and

• potassium carbonate, isopropyl bromide and cesium carbonate, and bromocyclohexane with potassium carbonate, and only afforded yields not higher than 52% in various solvents [41][42][43]. Recently, Alam and Keeting [37] explored the regioselectivity in the alkylation of variously substituted indazoles

Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• reported as substrates for nucleophilic substitutions using potassium fluoride [22]. The study is in progress now. Voltammetry characterization of the N-arylpyridoindazolium salts S1–S3 and their precursors, diarylamines A1–A3 The electrochemical investigation of the new salts was performed at a Pt

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• potassium carbonate was almost quantitative (97–99% yield). It is worth mentioning that the GBB reaction starting from the deacetylated substrate also leads to good results (83–91% of yield), but the overall yield is lowered due to a sluggish deacetylation reaction of 29. Sugar-based aldehydes were employed

Chiral bifunctional sulfide-catalyzed enantioselective bromolactonizations of α- and β-substituted 5-hexenoic acids

• Sao Sumida,
• Ken Okuno,
• Taiki Mori,
• Yasuaki Furuya and
• Seiji Shirakawa

Beilstein J. Org. Chem. 2024, 20, 1794–1799, doi:10.3762/bjoc.20.158

• -valerolactones 7 and 8, which are functionalized with sulfur and nitrogen, in high yields. Additionally, optically active δ-valerolactone 3a was converted to optically active epoxy-ester 9 upon treatment with potassium carbonate in methanol. Notably, the transformed products were obtained without any loss of

Oxidative fluorination with Selectfluor: A convenient procedure for preparing hypervalent iodine(V) fluorides

• Samuel M. G. Dearman,
• Xiang Li,
• Yang Li,
• Kuldip Singh and
• Alison M. Stuart

Beilstein J. Org. Chem. 2024, 20, 1785–1793, doi:10.3762/bjoc.20.157

• such as 5 (Scheme 2D) using large excesses of trichloroisocyanuric acid (TCCA) and potassium fluoride [24]. The iodine(V) fluorides were formed in good spectroscopic yields (79–94%), but only one product, tetrafluoro(4-fluorophenyl)-λ5-iodane 5, was isolated from the reaction mixture by performing

• iodine(I) precursor 8 (Table 1). Reacting 8 with 4 equivalents of trichloroisocyanuric acid (TCCA) and 6 equivalents of potassium fluoride in dry acetonitrile at 40 °C for 48 hours formed difluoroiodane 6 in a 90% spectroscopic yield (Table 1, entry 1). An iodosyl decomposition product 9 was also formed

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

• radical (potassium nitrosodisulfonate) [13] or catalytic systems like methyltrioxorhenium(VII) (MeReO3) [14] and 2-iodobenzenesulfonic acids (IBS)/Oxone® [15] led to either p-quinones or o-quinones, depending on the substituents in the para-position to the hydroxy group. Recently, hypervalent iodine

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• process, the carbonyl group at C-17 was stereoselectively attacked by α-lithio-α-methoxyallene at −78 °C to produce allene 25. A further cyclization reaction was induced by potassium tert-butoxide in the presence of catalytic dicyclohexyl-18-crown-6. The final 17-spirodihydro-(2H)-furan-3-one 27 was

• out, resulting in the corresponding N-tosylhydrazones 51a–c. Afterwards, the compounds were subjected to microwave irradiation in the presence of (3-azidopropyl)boronic acid and potassium or cesium carbonate, yielding 3-spiropyrrolidines 52a–c in high overall yields as 1:1 mixture of diastereomers

• an aldol condensation with benzaldehyde using potassium hydroxide in refluxing ethanol. The resulting enone 139 was reduced with sodium borohydride in methanol to give diastereoselectively the 17β-allylic alcohol. A successive treatment with m-CPBA in dichloromethane provided a mixture of epoxides

A fiber-optic spectroscopic setup for isomerization quantum yield determination

• Anouk Volker,
• Jorn D. Steen and
• Stefano Crespi

Beilstein J. Org. Chem. 2024, 20, 1684–1692, doi:10.3762/bjoc.20.150

• photon flux, i.e., the number of photons impinging a unit area of the sample in a unit of time [10]. Potassium ferrioxalate [39][40] is one of the most used actinometers while also some azobenzene derivatives have been reported as reaction quantum yield standards [11][22]. Although new chemical

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• . Additionally, stereoselectivity can be achieved by using potassium bis(trimethylsilyl)amide for deprotonation and methylation with MeI [33][39]. Any of these routes would yield methylated amino acids that can then be incorporated into an oligopeptide in solid-phase peptide synthesis (SPPS). Additionally, N

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• -oxyl radicals from NDHPI (Figure 17) [58]. The secondary and tertiary substrates selected were shown to undergo this transformation in moderate to good yields. The Yi group published a complementary method using stoichiometric potassium persulfate as the HAT reagent precursor (Figure 18) [59]. The

• yields quoted vs copper catalyst. Iron-catalysed intramolecular fluorine-atom-transfer from N–F amides. Vanadium-catalysed benzylic fluorination with Selectfluor. NDHPI-catalysed radical benzylic C(sp3)–H fluorination with Selectfluor. Potassium persulfate-mediated radical benzylic C(sp3)–H fluorination