Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• further hydrogen atom transfer from aldehyde 153 to tert-butoxy radical A leads to the formation of the acyl radical C, which adds to the double bond of alkene 152 to form the radical intermediate D. Recombination of radical D with tert-butylperoxy radical B affords the target product 154. The acylation

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

• described above, glycosides 81 were inactive against cancer and melanoma cell lines. 3,3-Diaryloxindole-N-glycosides The Friedel–Crafts acylation of isatin-N-rhamnoside β-16a with benzene (82a) afforded 3,3-diphenyloxindole-N-rhamnoside β-83a in 94% yield (Scheme 44) [63]. Deprotection of the latter

• afforded β-84a in 88% yield. Friedel–Crafts acylation of isatin-N-glycosides β-16c–e with benzene, toluene, anisole, and N,N-dimethylaniline and subsequent deprotection afforded 3,3-diaryloxindole-N-glycosides β-84b–l (Scheme 45) [63]. Some of the products showed antiproliferative activity against

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• reported over the years (Figure 2) [2]. Conventionally, benzophenones are synthesized by Friedel–Crafts acylation of benzoyl halides and aromatic compounds. However, the regioselectivity of Friedel–Crafts benzoylation at the desired position is difficult to control [9]. On the other hand, 2

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• ) [25] or β-keto esters (Scheme 1a, path 4) [26][27], the aldol reaction between aldehydes and S-ethyl acetothioate followed by oxidation with Dess–Martin periodinane (Scheme 1a, path 5) [28], the hydrolysis of α-oxo ketene dithioacetals (Scheme 1a, path 6) [29] and MgBr2·OEt2-catalyzed acylation of

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• for diverse applications in future studies. Keywords: condensation; co-timerization; dipyrromethane; Friedel–Crafts acylation; heterocycles; pyrrole; truxene; Introduction The scaffold of truxene (10,15‐dihydro‐5H‐diindeno[1,2‐a;1′,2′‐c]fluorene) and its congeners comprises three fluorene subunits

• derivatives (12, 15, and 17) in controlled manner (with appropriate equivalents of acetyl chloride and aluminium chloride) using one-to-threefold Friedel–Crafts acylation reaction(s) at 0 °C to rt in dichloromethane (DCM) solvent (Scheme 1 and Scheme 2). Subsequent condensation of thus prepared acetylated

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

• is that the reaction with methylhydrazine leads to two different regioisomers. Shen et al. used a concept developed by them for the C-acylation of β-ketoesters for the one-pot synthesis of pyrazoles. SmCl3-catalyzed acylation of these yields the 1,3-diketones 4, and after cyclization with hydrazine

• formation of alkenone intermediates, dialkyl acetylenedicarboxylates 147, as alkynoyl derivatives, are transformed to pyrazolones 149 by Michael addition–cyclocondensation with phenylhydrazine. In a consecutive one-pot reaction, the latter intermediates undergo O-acylation with aryl chlorides to give N

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• -methoxyethylamine. Attempts to obtain directly 2-oxoazetidine carboxylic acid (or its decarboxylation product) or its trifluoroethyl ester by running the synthesis with water or trifluoroethanol were also unsuccessful. Acylation of the π-excessive double bonds of N-alkylindole and dihydropyran by the in situ

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

• )-spiro[cholest-5-en-3,2’-[1,3,4]-oxadiazoline] (99) through the acylation of semicarbazone 98 using freshly distilled acetic anhydride and pyridine at 80 °C [55]. Semicarbazone 98 was initially obtained via condensation of cholest-5-en-3-one (97) with semicarbazide hydrochloride in a refluxing ethanol

• 140a,b (α/β 35:65), which were successfully separated. The following aminolysis of the isolated compounds was achieved by microwave heating using 3 equivalents of butylamine in ethanol at 180 °C. Finally, formation of morpholinones 142 and 143 was accomplished by N-acylation of the corresponding amino

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• bisorbicillinoid family. Substrate 33 for SorbC-catalyzed enzymatic transformation was synthesized in 3 steps from phenol 35 via formylation and subsequent reduction to introduce a methyl group, followed by a Friedel–Crafts acylation with 36 (Scheme 4B) [39][40]. The in vitro enzymatic transformation of 33 by

Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ³-iodanes

• Thomas J. Kuczmera,
• Pim Puylaert and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

• to undesired oxidations of the triple bond. The behavior of secondary benzylic alcohols was tested next, giving 4-methylacetophenone (4t) in an excellent yield of 97% and 1-indanone (4u) in 46%. It is worth noting that for some derivatives oxidized by method A, an acylation of the alcohol was

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• ), whose sequential acylation process by iso(thio)cyanates 3a–h gives rise to the asymmetric (thio)urea derivatives (intermediate II). The spontaneous nucleophilic attack of the (thio)amide nitrogen on the terminal methyl ester function at C-4 of the starting azo-ene system provides a regioselective

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• photocatalytic mechanism. Photoredox-catalyzed hydroacylation of olefins with aliphatic carboxylic acids. Acylation–aromatization of p-quinone methides using carboxylic acids. Visible-light-induced deoxygenation–defluorination for the synthesis of γ,γ-difluoroallylic ketones. Photochemical hydroacylation of

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• moiety in N-furfuryl-N-benzylmaleamic acid, formed by acylation of N-benzyl-N-furfurylamine with maleic anhydride, adopts a favorable conformational structure thanks to two activating electron-withdrawing groups and participates in the formation of the corresponding IMDAF product in oil medium rapidly

• reaction, the acylation is followed by an intramolecular Diels–Alder reaction and the amide intermediate (a sample compound has been previously isolated and fully characterized as a result of detailed studies) is in equilibrium with the final product at room temperature in polar solvents such as DMSO

Kinetically stabilized 1,3-diarylisobenzofurans and the possibility of preparing large, persistent isoacenofurans with unusually small HOMO–LUMO gaps

• Qian Liu and
• Glen P. Miller

Beilstein J. Org. Chem. 2024, 20, 1099–1110, doi:10.3762/bjoc.20.97

• substituents, respectively, were also attempted but without success. In these cases, the sterically congesting ortho isopropyl and tert-butyl groups stymie the Friedel–Crafts acylation step leading to diketone (Scheme 1). Experimental and computational studies of 1,3-diarylisoacenofurans Purified

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• reactions (over 10-gram scale) using diaminomaleonitrile (15) as a starting material in accordance with the procedure in the literature (Scheme 1) [27]. The first step is the acylation with oxalyl chloride to yield 14 followed by a reaction with SOCl2 in the presence of cat. DMF to obtain dichloropyrazine

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• employed as acylation reagents [1][2][3]. The strong C–F bond makes acyl fluorides relatively stable towards hydrolysis and easier to handle than other acyl halides [4][5][6][7][8]. Their reactions with nucleophiles are typically less violent than for the corresponding acyl chlorides with acyl fluorides

• of all these properties mean that acyl fluorides can provide significant advantages over acyl chlorides, especially for challenging acylation reactions [13][14]. Nevertheless, acyl chlorides still dominate in the literature; however, the recent development of safer and more practical synthetic routes

• unreliable isolation of acyl fluoride intermediates, we next considered whether BT-SCF3-mediated deoxyfluorination of carboxylic acids could be coupled with a subsequent acylation in an overall one-pot process. Selecting amines as nucleophilic coupling partners, a short optimisation study was carried out to

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• fused imidazotetrazolodiazepinones (Scheme 2A) [37]. The Gámez-Montaño group introduced a one-pot synthesis of Ugi-azide/N-acylation/Diels–Alder/dehydration reactions for isoindolin-1-one and 1,5-DS-T in a linked manner (Scheme 2B) [41]. The Ding group developed sequential Ugi-azide/Ag-catalyzed

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• the ability of the amino group in porphyrin 5 to enter acylation reactions with 4-(N-maleimido)benzoyl chloride (8, prepared in situ from 4-(N-maleimido)benzoic acid (9) and oxalyl chloride) and chloroacetyl chloride (10) with the aim of using these compounds for further functionalization. The

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• -wavelength absorption at 458 nm, while acylation led to a hypsochromic shift of the maximum in compounds 2a–c to 423–426 nm (Table 1). The intensity of this absorption band decreased with increasing steric hindrance in the order R = acetyl (i.e., 2a) > propionyl (i.e., 2b) > phenylacetyl (i.e., 2c). N

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• ]pyridine (13c, 54% combined isolated yield). As shown for N-acylated target compounds 16a–f, the acylation of 6-bromo-2,3-dihydro[1,3]thiazolo[4,5-b]pyridines 13a–c, affording target compounds 14a–c, proceeded under mild conditions with a suitable acyl chloride reagent and triethylamine as base in DCM. It

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• diverse dibenzodiazepinones via a copper-catalyzed C–N bond coupling between 2-halobenzoates and o-phenylenediamines leading to a key intermediate that undergoes an intramolecular N-acylation to afford the corresponding dibenzodiazepinone structure in high yields (Scheme 1b) [14]. Another innovative

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• , and aryl bromides as bromination reagents are limited. Wan and Li, respectively, demonstrated a few examples of a one-pot N-acylation and C5–H bromination of 8‑aminoquinolines using acyl bromines acting as both acyl and halide donors [25][26]. The groups of Lei and Fang independently realized the

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• ], Friedel–Crafts acylation [12], radical cascade reactions [2][13], and photoinduced radical cyclizations [14][15][16][17]. However, these methods often suffer from drawbacks such as harsh reaction conditions and the requirement of transition-metal catalysts. Although photocatalyzed cyclization reactions

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• of 3,4-dimethoxybenzaldehyde with 5-substituted 2-picoline derivatives in low to moderate yields ranging from 13% (2f) to 65% (2a) (Scheme 2). The amino-substituted derivative 2b was synthesized by reduction of the nitrostyrylpyridine 2a with Pd/C and hydrazine in 83% yield. Subsequent acylation of

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• synthesis of carbonates from CO2 [24][25][26] and the synthesis of oxazolidines from isocyanates and epoxides [27]. Furthermore, their application in primary hydroxy group selective acylation of diols [28] and their use as organophotoredox catalysts [29][30] is known. The latter mentioned catalysts are