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

• preparing spiro α-methylene-β-lactones from different steroidal propargylic alcohols [13]. The procedure involves a one-pot Pd-catalyzed cyclocarbonylation of alkynols using 5 mol % of Pd(CH3CN)2Cl2 as a catalyst precursor and 30 mol % of 2-(dibutyl)phosphine-1-(2,6-diisopropylphenyl)-1H-imidazole as

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• determined using a combination of NMR spectroscopy and chemical derivatization experiments, adding new members to this class of imidazole-containing natural products such as the nocarimidazoles A and B reported from a marine-derived actinomycete Nocardiopsis sp. before [126]. Compound 21 was determined to be

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• , with Kd values from micromolar (for monovalent galactosides) to nanomolar range (for di- and multivalent derivatives) [5][6][7][8]. For the monovalent system, it has been shown that aromatic aglycons favored “T-shaped” CH...π interactions with the protons of the His50 imidazole in the carbohydrate

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

• imidazole and pyrazine pharmacophores, are well represented in the area of medicinal chemistry since they possess pharmacological properties as mammalian target of rapamycin (mTOR) inhibitors [7], adenosine triphosphate (ATP) competitive inhibitors of the insuline-like growth factor 1 (IGF-1) receptor

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations

• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2024, 20, 1278–1285, doi:10.3762/bjoc.20.110

• well known that the hydrogen atom at the C2 carbon atom of the imidazole core is more acidic as those in the C4/C5-position, where the methyl groups are expected to also have a significant effect on the molecular interactions. Platinum complexes using the 4,5-dimethylimidazole motif as a ligand were

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• -membered aromatic azacycles, imidazole completely failed to undergo the present N-alkenylation, whereas the reaction of 1,2,4-triazole was too sluggish to allow for the isolation and unambiguous characterization of the expected product. Next, the reaction of pyrazole (2a) was explored using different

• (Scheme 3c). It is important to note that the azole nucleophile preferentially adds to the carbon atom that can better stabilize a positive charge, as demonstrated by the regioselectivities observed with unsymmetrical alkynes. The failure of imidazole to participate in the iodo(III)azolation may be

• between 4ba and 4-methoxybenzenethiol furnished the N,S-substituted olefin 7 in 59% yield. The treatment of 4aa with stoichiometric CuI and ʟ-proline effected the iodine(III)-to-iodine(I) conversion to give the vinyl iodide 8 in 76% yield. Compound 8 was used for the Ullmann coupling with imidazole

Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• tridentate chiral ligands: PyBOX [15] and PyBidine [16]. Additionally, we explored further modifications by substituting the pyridine moiety with an imidazole ring in ligand III (Figure 1), motivated by DFT calculations (see Supporting Information File 1, part S4) which confirmed that imidazole has a similar

• derivatives possess similar enantioselectivity. However, compound IV is less catalytically active, probably due to the lower acidity of protonated 1H-imidazole than 1H-tetrazole [17]. Conclusion In this study, we successfully synthesised enantiomerically pure stereoisomers of 2,2'-(pyridin-2,6-diyl)-bis

• enantioselectivity with a cis configuration at position 5 relative to position 2. Additionally, when mixed configurations were present at position 2 in tridentate ligands (Ib and IIb), the 2R configuration facilitated more effective chirality transfer. Substituting the pyridine moiety with an imidazole in ligands

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• imidazole in binding buffer (10, 20, 50, and 500 mM imidazole). Fractions were run on an ExpressPlusTM PAGE Gel (GenScript) and protein was visualized using Coomassie Brilliant Blue G-250 (VWR). Fractions containing Hyg17 were pooled and further purified using a HiLoad 16/600 Superdex 75 pg size exclusion

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• , TBAI, R–X (a: MeI, b: BnBr, c: BrCH2CCH3, d: BrCH2CN, e: Br(CH2)4N3), DMF, rt, 45% (10a), 59% (10b), 45% (10c), 21% (10d), and 45% (10e); (b) TBSCl, imidazole, DMAP, DMF, rt, 83% (11a), 78% (11b), 57% (11c), 62% (11d), and 65% (11e); (c) 25% TFA in THF aq, 0 °C, 77% (12a), 77% (12b), 50% (12c), 96

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• column (GE healthcare) at 5 mL/min. The column was washed with 10 mM phosphate-buffered saline (Medicago), 500 mM NaCl and 50 mM imidazole before elution of the protein using the same buffer with a gradient from 50 mM to 500 mM imidazole (G-Biosciences) over 15 column volumes. Pooled fractions were

• passed through a 0.45 µm syringe filter prior to affinity chromatography purification using 1 mL HisTrap™ HP column (Cytiva) preequilibrated with buffer A and an NGC chromatography system (Bio-Rad). After loading the cleared lysate, the column was washed with buffer A + 50 mM imidazole (Sigma-Aldrich

• , Merck, #56749) to remove all contaminants and unbound proteins. CMA1 was eluted by a 20 mL linear gradient from 50 mM to 500 mM imidazole in buffer A. The fractions were analyzed by SDS-PAGE with 15% gel and those containing CMA1 were collected and deprived of imidazole by buffer exchange in buffer A

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• )2–Y (Y = OCH3, OH, and imidazole)). The new amphiphiles quantitatively self-assemble into ≈2 nm-sized aromatic micelles in water independent of the side-chain. Importantly, efficient water-solubilization and nonionic surface modification of various nanocarbons (e.g., fullerene C60, carbon nanotubes

• , and graphene nanoplatelets) are achieved through noncovalent encircling with the bent amphiphiles. The resultant imidazole-modified nanocarbons display a pH-responsive surface charge, as evidenced by NMR and zeta-potential measurements. In addition, solubilization of a nitrogen-doped nanocarbon (i.e

• technology. We here report pyridinium-based, bent aromatic amphiphiles PA-R, featuring a pyridinium salt (Py-R+·Cl−) as the key motif, capable of providing both a cationic hydrophilic hinge and a variety of nonionic side-chains (i.e., CH3 and CH2CH2(OCH2CH2)2–Y (Y = OCH3, OH, and imidazole); Figure 1b). The

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• .). The protein was eluted using a stepwise gradient of imidazole in lysis buffer (20–500 mM imidazole). The buffer was replaced with lysis buffer using an Amicon Ultra centrifugal filter with a suitable molecular mass cutoff (Merck Millipore). Recombinant AvaA1 and AvaA3 obtained in our previous study

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• just three decades (Figure 1) [2]. In particular, cyclic diaminocarbenes based on the imidazoline, benzimidazole, or imidazole ring system (A–C) have led to a myriad of applications in organometallic chemistry, homogeneous catalysis, and materials science, to name just a few [3][4][5]. Due to their

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• , United States, Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States 10.3762/bjoc.19.142 Abstract 2,2’-Bis(4-dimethylaminophenyl)- and 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole ((N-DMBI)2 and (Cyc-DMBI)2) are quite

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• 3–5 h (TLC control). Meanwhile, the disappearance of the diazo reagent was considerably slower in the case of more basic heterocycles (pyrazoles, indolines, tetrahydroquinolines), taking anywhere from 16 to 24 hours, and in some cases (imidazole, 7-azaindazole, ethyl isonipecotate, hexamethylenimine

• product 6b in high yield. The reaction with methyl pyrrole-2-carboxylate resulted in the isolation of only the C–H insertion product 9c in low yield. Similar reaction progress was observed in the case with imidazole, the product N–H insertion was observed only in trace amounts (according to NMR data of

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• trifluoromethylated 1,2,4-triazoles were synthesized with excellent regioselectivities in [3 + 2] cycloaddition reactions of trifluoromethylated hydrazonoyl chlorides with imidates, amidine and 1H-benzo[d]imidazole-2-thiols, all of which were individually reported by Wang, Deng and Cai, respectively [77][78][79

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• proved the promising anti-PD and metallophoric effect, especially towards intracellularly relevant copper(I) ions, of X1INH (1-methyl-1H-imidazole-2-carboxaldehyde isonicotinoyl hydrazone) [32]. This year, we evaluated the effects of the presence of three methoxy substituents in an N-acylhydrazone

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• -1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole, has been obtained from addition of HPO3Et2 across the central C=C bond of bis(1,3-dimethylbenzoimidazolinidin-2-ylidene) [25], 12 dimers have generally been obtained by reductive electrochemical or chemical dimerization of 1+ cations

• molecular C2 symmetry, while the Y–C–C–Y torsion angles for 1h2 and 1e2 are 149.4° and 140.3°, respectively, and thus both intermediate between the perfectly staggered (180° torsion) and neighboring eclipsed conformation (120°). The imidazole rings in the previously reported and present dimer structures are

• delocalize spin density. The 1H structures (Figure 4) are similar to those of other DMBI-H structures in the literature [34][48][49][50] (and are compared in more detail in Supporting Information File 1, Table S2); in all cases the imidazole ring is folded in a “puckered envelope” conformation with the 2-Y

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

• having a triisopropoxy(propyl)silyl ((-CH2)3Si(OiPr)3) substituent on the imidazole ring through in situ transmetallation. One of these complexes, 78a, was successfully anchored on mesoporous silica MCM-41 to afford a new heterogeneous catalyst (Scheme 27). Both compounds were subsequently used as

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

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

• performance in OLED devices [1]. 4CzIPN is a donor–acceptor-type system where carbazole donor ligands are bound to the benzonitrile acceptor core moiety. In this work we have substituted the carbazole donors with 5H-benzo[d]benzo[4,5]imidazo[1,2-a]imidazole (benzoguanidine) ligands to give 4BGIPN, see Figure

• containing a rigid benzoguanidine ligand in its molecular structure. Results and Discussion Synthesis and structure 4BGIPN was prepared in 70% yield by aromatic nucleophilic substitution reaction from 2,4,5,6-tetrafluoroisophthalonitrile and 5H-benzo[d]benzo[4,5]imidazo[1,2-a]imidazole (benzoguanidine) after

• mineral oil with diethyl ether and dried prior to use. 5H-Benzo[d]benzo[4,5]imidazo[1,2-a]imidazole (benzoguanidine) was obtained according to the literature protocol [10] while 2,4,5,6-tetrafluoroisophthalonitrile was purchased from Fluorochem Ltd. and used as received. 1H and 13C{1H} NMR spectra were

Metal catalyst-free N-allylation/alkylation of imidazole and benzimidazole with Morita–Baylis–Hillman (MBH) alcohols and acetates

• Olfa Mhasni,
• Jalloul Bouajila and
• Farhat Rezgui

Beilstein J. Org. Chem. 2023, 19, 1251–1258, doi:10.3762/bjoc.19.93

• Toulouse, France University of Tunis El Manar, Laboratory of Organic Chemistry, Faculty of Sciences, Campus, 2092 Tunis, Tunisia 10.3762/bjoc.19.93 Abstract A highly α-regioselective N-nucleophilic allylic substitution of cyclic MBH alcohols and acetates with imidazole or benzimidazole, in toluene at

• reflux with an azeotropic distillation, was successfully carried out with no catalysts or additives, affording the corresponding N-substituted imidazole derivatives in good yields. On the other hand, in refluxing toluene or methanol, the aza-Michael addition of imidazole onto acyclic MBH alcohols was

• performed using DABCO as an additive, leading to the corresponding 1,4-adducts in 70–84% yields. Keywords: allylic substitution; aza-Michael addition; imidazole; Morita–Baylis–Hillman; Introduction Morita–Baylis–Hillman (MBH) adducts are multifunctionalized compounds having both a hydroxy moiety and a

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• )-enolates were calculated for products 3b and 3d, which possess either an alkyl (ethyl) or an aryl (phenyl) substituent on the stereogenic center. To probe the nature of the imidazole moiety, enolates for products 3g and 3i were also calculated (with a shorter alkyl chain to simplify the calculations

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

• -1,2-diketone [21][22][23][24][25]. However, the direction of the transformation in each case depends on the structure of the bridge fragment. Thus, for example, the 1,3,5-hexatriene cyclization does not occur for pyrazole 1 and imidazole 2 derivatives, and the obtained products are formed exclusively