Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• binds free tryptophan selectively in aqueous media. Furthermore, it is capable of binding to tryptophan within model tripeptides. The naphthalene functionality in the glucose-derived receptor enables the study of guest binding using fluorescence spectroscopy. Keywords: amino acids; macrocyclic

• in water [21]. Crown ether 1 is particularly suited for the sensing of Trp methyl ester, which it binds with a higher affinity than the Phe and Tyr esters. Additionally, the binding of Trp-OMe results in a highly efficient fluorescence quenching of the naphthalene unit in the receptor. Herein, we

• protons of 1 shifted downfield and a marginal downfield shift of several crown ether protons as well as H-1 and H-3 of the glucopyranose was also observed. These observations suggest that the main interaction between 1 and H-Trp-OH is the π–π stacking between the naphthalene unit of 1 and the indole

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• capable of being cleaved by two possible orthogonal pathways. The first method involves a relay approach by catalytic hydrogenation followed by the application of 1,8-bis(dimethylamino)naphthalene (bDMAN) which selectively cleaves the protecting group while keeping the other ester groups intact. The

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• in yields ranging from 70% to 99%, with minimal byproducts. Even more complex substrates, like naphthalene and pyrene derivatives, underwent efficient oxidation, suggesting the method’s utility in functionalizing more challenging aromatic frameworks. The mechanism of this reaction was explored in

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• to 1, the spectrum of 1•+ is characterized by a downshift by 11 cm−1 of the ν(CC)exo-CBD vibration, together with the emergence of a new band at 1567 cm−1 which was assigned to a ν(CC)NAP mode (CC stretching mode of the naphthalene moieties) on the basis of the normal mode calculation (Table S1 in

• Supporting Information File 1). Upon second oxidation, the former Raman vibrational band upshifts by 24 cm−1 for 12+, and the naphthalene ν(CC)NAP stretching one disappears. Overall, the evolution of the CBD breathing mode, throughout the series 1→1•+→12+ is 1700 → 1689 → 1713 cm−1. Figure 5 shows the Raman

• indicator of structural uniformity within the NAP rings, the three-folded band in 2•+ suggests the presence of different CC bonds in the naphthalene groups. The Raman spectrum of the doubly oxidized form also showed a similar profile to that of 2•+, with the only change of the relative intensities of the

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• in the final product 37 (Scheme 28) [46]. Analogously, benzo[g]chromene derivatives 38 were achieved starting from 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes and malononitrile with copper triflate as catalyst and ultrasonic irradiation (Scheme 29) [47]. Naphthalene-annulated 2-aminothiazoles

• 39 were prepared exploiting the multicomponent reaction by using aminonaphthalenes, CS2 and secondary amines. The mechanism involved the Ullmann-type coupling of the bromo(amino)naphthalene with the dithiocarbamate salt followed by intramolecular nucleophilic attack of the naphthalene amino group to

• isoxazole-linked imidazo[1,2-a]azines 35. Synthesis of 2,3-dihydro-1,2,4-triazoles 36. Synthesis of naphthopyrans 37. Synthesis of benzo[g]chromene derivatives 38. Synthesis of naphthalene annulated 2-aminothiazoles 39, piperazinyl-thiazoloquinolines 40 and thiazolocoumarins 41. Synthesis of furo[3,4-b

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• methodology, the previously known naphthalene dibromide 14 was prepared in two steps from 1,8-DHN (19) [56] serving as the second coupling partner. The Pd-catalyzed cascade reaction between 14 and 22 afforded the targeted benzo[j]fluoranthene 18 in 52% yield. Overall, the synthesis of 18, which was used as

• synthesis of benzo[j]fluoranthene 23 in six steps (Scheme 3). In this sequence, 1,8-DHN (19) was first converted to 1-acetoxy-8-methoxynaphthalene (24) via a selective mono-methylation of 19 followed by acetylation by acetyl chloride in 88% yield over two steps. The more electron-rich ring of naphthalene 24

• ring with the -OMe group on 25, while the halogen (bromine) is on the opposite ring with the -OMe group on naphthalene 30. This small yet important difference allowed us to synthesize benzo[j]fluoranthenes 23 and 28 selectively with free -OH groups at different positions. Bromonaphthalene 30 was

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• derivatives, and is, thus, more pronounced for the naphthalene-bridged compounds. Likewise, the increased size of the conjugated π-system also led to a red shift of the absorption bands in comparison with the ones of the corresponding norbornadiene derivatives without acetylene bridges (1b,e) [29][30

• - and 2,6-position of the naphthalene unit resulted in low quantum yields, whereas the attachment of the norbornadiene at the 1- or 1,4-position led to significantly higher quantum yields, which is in accordance with previous observations with naphthyl-substituted derivatives [29][30]. Apparently, there

Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• the desired products 2g–n in 68–95% yield. Furthermore, a substrate containing a naphthalene moiety was also compatible with the reaction conditions, giving the corresponding ring-fused product 2o in 40% yield. It is worth noting that when the N-substituent was phenyl, benzyloxy, or phenylamino, the

• group (trifluoromethyl, fluoro, chloro) was located on the phenyl ring, various amounts of 4-substituted isoquinolinone derivatives 2k,m,n were observed along with the formation of 3h,j,k, respectively. Furthermore, a substrate containing a naphthalene unit was also compatible with the reaction

Synthesis and characterization of 1,2,3,4-naphthalene and anthracene diimides

• Adam D. Bass,
• Daniela Castellanos,
• Xavier A. Calicdan and
• Dennis D. Cao

Beilstein J. Org. Chem. 2024, 20, 1767–1772, doi:10.3762/bjoc.20.155

• Adam D. Bass Daniela Castellanos Xavier A. Calicdan Dennis D. Cao Chemistry Department, Macalester College, 1600 Grand Avenue, Saint Paul, Minnesota 55105, United States 10.3762/bjoc.20.155 Abstract We report the synthesis and characterization of naphthalene and anthracene scaffolds end-capped by

• robust polymers, supramolecular assemblies, and (opto)electronic materials. The vast majority of this research has focused on 1,2,4,5-benzene (pyromellitic), 1,4,5,8-naphthalene, and 3,4,9,10-perylene diimides. Beyond these, researchers have demonstrated that translocating the cyclic imides around the

• 1,2,5,6- [9][10] and 2,3,6,7-naphthalene diimides (NDIs) have been produced and utilized in electronically active polymers (Figure 1). The linear extension of 1,4,5,8-naphthalene diimide to produce tetracene [11] and hexacene [12] diimides, some with interesting properties such as near-IR absorption, has

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

• (PAHs) by cytochrome P450 (CYP) and other metabolic enzymes [7][8]. Main metabolic pathways form quinone isomers of benzo[a]pyrene [8], naphthalene [9][10], and benzene [11]. Numerous methods for the oxidation of phenols or their derivatives to quinones have been described [12]. Oxidation with Fremy’s

• acetals. However, the methoxylated products from electrochemical oxidation of chrysen-1-ol (3b) and chrysen-6-ol (3d) rapidly hydrolysed to quinones during purification and could not be isolated. The attempted electrochemical oxidation of naphthalene-1-ol (1b) was unsuccessful; only small traces of

• Information File 1). Naphthalene-1-ol (1b) gave a well-defined oxidation peak at 0.95 V (vs Fe/Fe+) while naphthalene-2-ol (1a) showed an oxidation peak at 1.14 V (vs Fe/Fe+). The oxidation peak potential difference between 1b and 1a was 190 mV. PAHs undergo rapid irreversible chemical reactions upon electron

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

• isoelectronic π-system. For example, naphthalene and isobenzofuran (1) both possess 10 π-electrons and are calculated to have HOMO–LUMO gaps of 4.73 and 4.05 eV, respectively. The incorporation of 1,3-diphenyl substituents (compound 2) or 1,3-diphenylthio substituents (compound 4) lowers the HOMO–LUMO gaps of

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

• * level of theory (depicted in Figure 4 and Figure 5). Figure 4 reveals that the HOMOs of 1a–7a are predominantly localized on the π-donor units, such as benzene and naphthalene, with an illustration in the case of 6a. On the contrary, the LUMOs are delocalized across the entire π-systems, while also

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• variety of 3,4-benzocoumarin derivatives. Our investigations commenced with 2-naphthol (1), and the results are presented in Table 2. Various substituted naphthols with a broad range of substituents on the naphthalene unit were well tolerated in the reaction, affording the corresponding products 3aa–aq in

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

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• 6-membered rings containing a sulfoxide moiety. For instance, Grainger and co-workers designed a series of naphthotrithiin-2-oxides, such as 47, to act as SO transfer reagents (Scheme 13) [79]. These triplet SO precursors were prepared by treatment of 1,8-naphthalene dithiols with thionyl chloride

• , along with the 5-membered 1,8-naphthalene disulfide 49 resulting from the ring contraction of precursor 47. Such SO transfer process, favoured by the peri-interaction existing in the trisulfide-2-oxide substrate, was also successfully promoted by light and the cyclic sulfoxide 50 was obtained under

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• , Pushkin str. 1a, 355017 Stavropol, Russian Federation 10.3762/bjoc.20.24 Abstract The possibility of functionalization of dipyrido[3,2-e:2′,3′-h]acenaphthene containing a quino[7,8-h]quinoline fragment and being a highly basic diazine analog of 1,8-bis(dimethylamino)naphthalene (“proton sponge”) has been

• pyridine rings, the naphthalene core at positions 5(8) and the CH2CH2 bridge (dehydrogenation) undergo chemical modifications under mild conditions, giving the corresponding acenaphthylenes. The latter can also be obtained in an unusual way by tele-elimination from 5,8-dibromodipyridoacenaphthene by

• forced to strongly repel each other in space, can lead to a sharp increase in basicity [8]. Thus, quino[7,8-h]quinoline (3), first obtained in the Staab group [9], already exceeds in basicity not only quinoline itself, but also 1,8-bis(dimethylamino)naphthalene (1, “proton sponge”) (Scheme 1; pKa values

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• using heme-containing oxygenases (cytochrome P450 monooxygenases, styrene/indole monooxygenases, flavin-containing monooxygenases, Baeyer–Villiger monooxygenases, etc.) or non-heme iron oxygenases (naphthalene dioxygenases, multicomponent phenol hydroxylases) [5][6][7][8]. The synthetic approaches

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

• trimethylgallic acid bearing multiple methoxy groups afforded the desired product 3ma in excellent yield (99%). Noteworthy to mention, substrates containing naphthalene, furan, and thiophene rings also efficiently underwent reaction leading to the quinoline C5-brominated products in excellent yields (3na–pa). In

• contrast, side products, substituted on the naphthalene, furan, or thiophene ring were not detected. This protocol was also compatible with linear, branched, and cyclic aliphatic acid-derived substrates (3qa–va). Surprisingly, small ring-containing substrates displaying significant ring strain were stable

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• through the pyrolysis of indane-1,2,3-trione. When BBD 13 was subjected to reflux conditions with bis(cyanomethyl) compounds 14a (a benzene derivative) and 14b (a naphthalene derivative) in acetonitrile, the desired POAs 15a and 15b were obtained with yields of 25% and 48%, respectively (Scheme 2). It was

• )2C6H3, (c) H), followed by aromatization in acidic conditions, resulted in the formation of three [3]naphthalene regioisomers 43a–c, 44a–c, and 45a–c with excellent yields of up to 94%. The synthesized PAHs 43a, 44a, and 45a with diverse geometries exhibited interesting absorption and emission

• from benzene (53a), naphthalene (53b), and anthracene (53c) with compound 52, the desired target azaacenes 54a–c were successfully obtained in yields ranging from 68% to 84% (Scheme 11). As anticipated, there was a notable red shift observed from 54a to 54c, which can be attributed to the expansion of

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• ]. Similarly, Grobelny et al.'s work provides valuable insights into the impact of two quinoxaline derivatives, hexyloxy-substituted diphenylquinoxaline (HPQ) and naphthalene-fused-quinoxaline (NFQ), as auxiliary acceptors on DSSC performance. The comparison between Qx34 and Qx35 highlights the importance of

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• sulforhodamine B were purchased from Sigma-Aldrich, USA. 4-Amino-3-hydroxy-1-naphthalene sulfonic acid was purchased from Fluka, India. Sulfuric acid was purchased from ACROS Organics, Belgium and diethyl ether was purchased from VWR-Prolabo Chemicals, Belgium. Liposomes preparation, extrusion, and purification

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• cyano (3d) at the para-position, were amenable to the reaction conditions affording the product in 52% yield. Bulky groups, such as naphthalene were also suitable forming product 3e in 57% yield, highlighting the functional group tolerability of this reaction. Next, the scope of the reaction for aryl

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

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

• the prefused building block in a 49% yield. Then naphthalene and phenanthrene residues were introduced into compound 33 through Suzuki coupling reaction, the corresponding precursors 34 and 36 were obtained respectively in high yields. The final cyclodehydrogenation using DDQ and TfOH proceeded

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• two 7-(arylethynyl)-1,8-bis(dimethylamino)naphthalene fragments was prepared via the Glaser–Hay oxidative dimerization of 2-ethynyl-7-(arylethynyl)-1,8-bis(dimethylamino)naphthalenes. The oligomers synthesized in this way are cross-conjugated systems, in which two conjugation pathways are possible: π

• -conjugation of 1,8-bis(dimethylamino)naphthalene (DMAN) fragments through a butadiyne linker and a donor–acceptor aryl–C≡C–DMAN conjugation path. The conjugation path can be “switched” simply by protonation of DMAN fragments. X-ray diffraction, UV–vis spectroscopy and cyclic voltammetry are applied to analyze

• the extent of π-conjugation and the efficiency of particular donor–acceptor conjugation path in these new compounds. X-ray structures and absorption spectra of doubly protonated tetrafluoroborate salts of the oligomers are also discussed. Keywords: 1,8-bis(dimethylamino)naphthalene; cross-conjugated