Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• 1a–j, various substituents at the nitrogen were tolerated including aryl, (substituted) benzyl and alkyl substituents (including tryptamine, cyclohexyl, propargyl, and allyl) and furnished the N-heteroaryl amidines 3a–u in high or moderate yields (46–98%) (Scheme 2). There was no apparent substituent

• effect on the yield of the final compounds 3 observed. The structures of compounds 3a–u were confirmed by IR, 1H and 13C NMR spectroscopy (Figures S1‒S44 in Supporting Information File 1) as well as by high-resolution mass spectrometry (HRMS). X-ray data obtained for compound 3g gave us final proof of

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• indicate these reactions are much more complex. For example, in earlier computational studies of anisyl-derived iodonium ylides 63a/b, Vasdev and Liang found a steric explanation for the ortho-substituent effect (Figure 13), contrary to that observed for 62a/b. They showed how the ortho-methoxy group in

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• groups or electron-donating groups proceed smoothly without showing any significant substituent effect. Also, there was no effect of the substituent on yields and reaction time. In 2011, Zhang and Shi [62] reported the Clauson–Kaas synthesis of N-substituted pyrroles 21 through the reaction between

A study of the DIBAL-promoted selective debenzylation of α-cyclodextrin protected with two different benzyl groups

• Naser-Abdul Yousefi,
• Morten L. Zimmermann and
• Mikael Bols

Beilstein J. Org. Chem. 2022, 18, 1553–1559, doi:10.3762/bjoc.18.165

• . These methods are so useful because virtually any chemical modification at the deprotected sites can be made followed by global deprotection of the O-benzyl groups with hydrogenolysis. Recently, we observed a strong substituent effect when substituted benzyl groups were used in these reactions with

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

• Dharmendra Das,
• Akhil A. Bhosle,
• Amrita Chatterjee and
• Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

• compounds matched well with the reported data indicating their successful formation. As such not much substituent effect was seen and the protocol worked well for phenols having electron-donating groups (EDG, products 2b–e, Scheme 3) or even strong electron-withdrawing groups (EWG, products 2n–p, Scheme 3

•  3). Once again, no prominent substituent effect was observed in terms of yields or reaction time. Next, we focused our attention on expanding the substrate scope to other electron-rich aromatic systems. The bromination of hydroquinone dimethyl ether was sluggish and a moderate yield (67%) of the

• aniline derivatives also worked well to afford the desired products in high yields (products 2u and 3j in Scheme 4). In all cases, no prominent substituent effect was observed in terms of yields and reaction time. Next, we planned to further diversify this halogenation protocol via automated grinding for

Synthesis of bis-spirocyclic derivatives of 3-azabicyclo[3.1.0]hexane via cyclopropene cycloadditions to the stable azomethine ylide derived from Ruhemann's purple

• Alexander S. Filatov,
• Olesya V. Khoroshilova,
• Anna G. Larina,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2022, 18, 769–780, doi:10.3762/bjoc.18.77

• cyclopropene 2e led to the formation of the diastereomer with all three substituents (at the cyclopropane ring) oriented in the same direction. A notable substituent effect on the reactivity of cyclopropene dipolarophiles 2 was observed for the reactions between PRP (1) and derivatives of 2,3-diphenylcycloprop

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

Borylated norbornadiene derivatives: Synthesis and application in Pd-catalyzed Suzuki–Miyaura coupling reactions

• Robin Schulte and
• Heiko Ihmels

Beilstein J. Org. Chem. 2022, 18, 368–373, doi:10.3762/bjoc.18.41

• identification of novel stable derivatives as well, such as 5b, 5c, and 5i. But unfortunately, there is no clear trend for a substituent effect on the reaction outcome, as both donor- and acceptor-substituted haloarenes resulted in essentially the same range of yields, i.e. from good yields (e.g., 4b, 4h, and 4j

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• experiments upon the substituent effect indicated that it was the steric, not the electronic factor, that ruled the reactivity and selectivity. The electron-donating alkyl groups should have facilitated reaction at the substituted ring, in contrast, the reaction occurred at the unsubstituted ring. This

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• investigation, the LS-FAS-Cu was also found to be an efficient catalyst for the synthesis of aminonaphthalene derivatives (Table 5). The substituent effect of aniline was examined systematically, and the results showed that anilines bearing electron-donating groups such as Me, OMe and t-Bu at the para-position

• amines such as morpholine (9j) also showed high reactivity in this reaction and 10j was obtained in 81% yield. The substituent effect of 2-(phenylethynyl)acetophenone was studied subsequently, and the results showed that fluoro, chloro, aliphatic chain and cycloolefin-substituted 2-(phenylethynyl

Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• with that for 1b. This substituent effect on the oxidation potential is typical for the reported NAr3 system [53]. Because the electron-donating group of the NAr3 unit destabilizes the MV state, the potential splitting for 1a is 50 mV smaller than that for 1b (Figure 2, top). Similar substituent

Click chemistry towards thermally reversible photochromic 4,5-bisthiazolyl-1,2,3-triazoles

• Chenxia Zhang,
• Kaori Morinaka,
• Mahmut Kose,
• Takashi Ubukata and
• Yasushi Yokoyama

Beilstein J. Org. Chem. 2019, 15, 2161–2169, doi:10.3762/bjoc.15.213

• cyano groups, the measured absorption maximum of the closed form was about 40 nm longer than the others in any solvent. The substituent effect observed here is different from the small substituent effect on the closed forms of the representative bisthienylhexafluorocyclopentenes 4c (R = H, 562 nm), 5c

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

• Ayato Yamada,
• Manabu Abe,
• Yoshinobu Nishimura,
• Shoji Ishizaka,
• Masashi Namba,
• Taku Nakashima,
• Kiyofumi Shimoji and
• Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

• at the para-position of the p-nitrophenyl group in 2a. As observed in the OP uncaging reaction at 365 nm, the efficiency of the TP-induced TEMPO uncaging reaction of 2a was almost three times higher than that of 2b in benzene. This is attributed to the substituent effect of the meta-alkoxy group on

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

• Tegene T. Tole,
• Johan H. L. Jordaan and
• Hermanus C. M. Vosloo

Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19

• . This will only be due to the substituent effect on the activity of the precatalyst. Effect of catalyst concentration Earlier studies indicated that 80 °C is the optimum temperature for 5d [10][11]. It was therefor decided to investigate the effect of the concentration of the precatalyst on the

Cationic cobalt-catalyzed [1,3]-rearrangement of N-alkoxycarbonyloxyanilines

• Itaru Nakamura,
• Mao Owada,
• Takeru Jo and
• Masahiro Terada

Beilstein J. Org. Chem. 2018, 14, 1972–1979, doi:10.3762/bjoc.14.172

• . Substituent effect at the hydroxylamine moiety.a Co-catalyzed reaction of N-alkoxycarbonyloxyanilines 1o–ab.a Supporting Information Supporting Information File 484: General procedure and analytic data for obtained products. Acknowledgements This work was supported by JSPS KAKENHI Grant Number JP16H00996 in

A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

• Liu-Pan Yang,
• Song-Bo Lu,
• Arto Valkonen,
• Fangfang Pan,
• Kari Rissanen and
• Wei Jiang

Beilstein J. Org. Chem. 2018, 14, 1570–1577, doi:10.3762/bjoc.14.134

• conformational change in response to the remote electronic substituents on the guests [34]. We wondered whether a similar behavior would be observed for ZB4. Consequently, a series of guests with different substituents in the para-positions of guest 3+ were employed to study the electronic substituent effect of

• the substituents of guests 12+ and 19+ are quite different in view of their electronic properties, they share very similar binding affinities. What is the underlying reason for the response of binding affinities to the electronic substituent effect on the guests? Luckily, single crystals of complexes

Cobalt-catalyzed C–H cyanations: Insights into the reaction mechanism and the role of London dispersion

• Eric Detmar,
• Valentin Müller,
• Daniel Zell,
• Lutz Ackermann and
• Martin Breugst

Beilstein J. Org. Chem. 2018, 14, 1537–1545, doi:10.3762/bjoc.14.130

• approach was used to accelerate the calculations [56][57]. For the analysis of the substituent effect, the B3LYP functional with Grimme’s dispersion correction D3 (Becke–Johnson damping) was employed together with the def2-SVP basis set for all non-metals and the def2-TZVP basis set for Co. Vibrational

[3 + 2]-Cycloaddition reaction of sydnones with alkynes

• Veronika Hladíková,
• Jiří Váňa and
• Jiří Hanusek

Beilstein J. Org. Chem. 2018, 14, 1317–1348, doi:10.3762/bjoc.14.113

• , substitution effects in the 3-(4-substituted phenyl) group of sydnones were studied and a relatively low Hammett reaction constant ρ ≈ +0.8 was estimated from four derivatives (MeO, Me, H and Cl). An even smaller dependence of the rate constants on the solvent polarity and substituent effect sensitivity (ρ

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• ligands. The substituent effect is attenuated by the positive charge at the iron atom in 1+–4+ ( = 5 cm−1), compared to 1–4 ( = 12 cm−1), respectively (Figure 3b, Table S1, Figures S7–S14, Supporting Information File 1) [78]. The unscaled energies of the DFT calculated C=O bands of 1+–3+ fit very well to

• resonances shift to lower field and the methyl proton resonances shift to higher field (CpR: 1+ → 2+ → 3+, CpR2: 3+ → 4+). This substituent effect is larger for the paramagnetically shifted resonances of 1+–4+ than for the diamagnetic complexes 1–4. In CD3CN, the treatment of 3 with Magic Green led to the

2-Iodo-N-isopropyl-5-methoxybenzamide as a highly reactive and environmentally benign catalyst for alcohol oxidation

• Takayuki Yakura,
• Tomoya Fujiwara,
• Akihiro Yamada and
• Hisanori Nambu

Beilstein J. Org. Chem. 2018, 14, 971–978, doi:10.3762/bjoc.14.82

• to benzophenone in the presence of Oxone® (2KHSO5·KHSO4·K2SO4) as a co-oxidant at room temperature. A study on the substituent effect of the benzene ring of N-isopropyl-2-iodobenzamide on the oxidation revealed that its reactivity increased in the following order of substitution: 5-NO2 < 5-CO2Me, 3

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• et al. [49] theoretically investigated the substituent effect of azidothiazoles in the azido–tetrazole equilibrium using the B3LYP/6-311G** level of theory. Their results showed that electron-withdrawing groups (–NO2, –CN) stabilize azide isomers while –NH2 and –OH groups shift the equilibrium to the

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• λmax,em are found in a range from 408.5 to 512.5 nm with Stokes shifts lying between 3900 and 2500 cm−1 (Table 6, entries 1, 2 and 4–6, Figure 6). This electronic substituent effect of R1 on the Stokes shifts was further corroborated by linear structure–property relationships based upon Hammett–Taft

NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones

• Ken Takaki,
• Makoto Hino,
• Akira Ohno,
• Kimihiro Komeyama,
• Hiroto Yoshida and
• Hiroshi Fukuoka

Beilstein J. Org. Chem. 2017, 13, 1816–1822, doi:10.3762/bjoc.13.176

• (Table 1, entries 5 and 18). Then, the substituent effect of benzils 1 was investigated (Table 2). Electron-donating groups decreased the reaction efficiency slightly. The yields were improved by catalytic amounts of MgCl2 as reported previously [15], whereas the isomer ratios of 4 were nearly unchanged

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• . Keywords: colorimetric sensor; DFT; molecular logic gates; rate constant; substituent effect; Introduction The development of new organic receptors for the detection of anions is of key interest to supramolecular chemists owing to the biological and environmental importance of anions [1][2][3][4][5][6][7

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• of substrates reached full conversion after 24 hours. Based on our findings that placing substituents on the phenyl ring, both in 2- and 4-benzylpyridines and irrespective of their electronic nature, has little influence on the yield of the reaction the largest substituent effect is expected to be on