Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles

• Arnaldo G. de Oliveira Jr.,
• Martí F. Wang,
• Rafaela C. Carmona,
• Danilo M. Lustosa,
• Sergei A. Gorbatov and
• Carlos R. D. Correia

Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84

• were then submitted to deprotection protocols as described in the literature [20][21]. However, the removal of the tosyl group of pyrroline 1b proved to be a challenging task. After several unsuccessful attempts to remove the tosyl group, we decided to evaluate the (p-nitrophenyl)sulfonyl (Ns) and (o

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

• molecule 5b. In the crystal packing (Figure S66 in Supporting Information File 1), molecules 5e tend to approach π-donor DMAN and π-acceptor p-nitrophenyl fragments, and the shortest distance between the two molecules is 2.810 Å (Figure S67 in Supporting Information File 1). The alternation of the C–C bond

• lengths in the aryl rings of molecules 5d and 5e may indirectly indicate the conjugation of the π-donor fragment with the π-acceptor p-nitrophenyl or p-cyanophenyl fragments. The qr parameter, calculated according to equation [32] (Figure 6) and characterizing the quinoid character of the aryl ring, was

• phenyl and p-methoxyphenyl derivatives) to 2.09 eV (for p-nitrophenyl derivative). Thus, the HOMO–LUMO gap is significantly reduced by the introduction of the electron-withdrawing substituent, while the introduction of a donor substituent, e.g., a OMe group, does not change this value. On the other hand

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

• Sarot Cheenpracha,
• Ratchanaporn Chokchaisiri,
• Lucksagoon Ganranoo,
• Sareeya Bureekaew,
• Thunwadee Limtharakul and
• Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

• according to experimental literature with slight modification [20]. α-Glucosidase (0.05 U/mL) and substrate, p-nitrophenyl-α-ᴅ-glucopyronoside (p-NPG) (1 mM) were dissolved in 0.1 M sodium phosphate buffer (pH 6.9). Fifty μL of sample (1 mg/mL in 10% DMSO) and 50 μL of α-glucosidase were preincubated at 37

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

• Pratibha Sharma,
• Raakhi Gupta and
• Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

• in a satisfactory yield. Thus, a series of these catalysts was screened. The best results in term of the yield (83%) and ee (90%) were obtained while using the catalyst having a p-nitrophenyl group on the other side of thiourea moiety in CCl4 in the presence of 4 Å molecular sieves (Table 16). The

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

• Pezhman Shiri,
• Ali Mohammad Amani and
• Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

• via intramolecular cyclization reaction of ketones 31, p-nitrophenyl azide (PNA, 32) and amino esters 33 has been described by Dehaen et al. The products were often obtained in good yield and in all cases with the retention of the configuration of the stereocenter. The reaction was carried out by

Chiral anion recognition using calix[4]arene-based ureido receptors in a 1,3-alternate conformation

• Tereza Horáčková,
• Jan Budka,
• Vaclav Eigner,
• Wen-Sheng Chung,
• Petra Cuřínová and
• Pavel Lhoták

Beilstein J. Org. Chem. 2020, 16, 2999–3007, doi:10.3762/bjoc.16.249

• atmosphere (5 atm) in an autoclave at room temperature provided compound 6 in 91% yield. The starting compound 5 was then reacted with commercially available isocyanates comprising p-nitrophenyl isocyanate, p-n-butylphenyl isocyanate, (S)-α-methylbenzyl isocyanate, and (R)-α-methylbenzyl isocyanate. The

• presence of p-nitrophenyl groups. At the same time, the singlets at 8.36 and 9.37 ppm reflected the ureido NH protons (DMSO-d6, 400 MHz, 298 K). The structures of the selected receptors 7a and 7d were further proven by single crystal X-ray studies. The calixarene 7a crystallised in a monoclinic system

• completed by the close contacts between carbonyl oxygen atoms (of the urea group) and S atoms (of DMSO), indicating possible chalcogen interactions [47][48], and the C=O···S=O distances were 3.269 and 3.308 Å (Figure 3a). The molecular packing was further strengthened by the π–π interactions of the p

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• ). None of the benzyl (Bn), phenyl (Ph), p-methoxyphenyl (PMP) or p-nitrophenyl (PNP) derivatives showed any activity [Figure 5A, wells 3–6, respectively]. On the contrary, both p-chlorophenyl (PCP) and p-fluorophenyl (PFP) showed the best photocleaving action, exhibiting a percentage of ds cleavages, as

• examine the transitions (S0 → T1 and S0 → S1) we find that there are major differences in the nature of the transitions. In particular, for the transition S0 → T1 the excitation is localized on the pyridine moiety for 12, while for 11 it is localized on the p-nitrophenyl group. As far as the S0 → S1

Palladium-catalyzed synthesis and nucleotide pyrophosphatase inhibition of benzo[4,5]furo[3,2-b]indoles

• Hoang Huy Do,
• Saif Ullah,
• Alexander Villinger,
• Joanna Lecka,
• Jean Sévigny,
• Peter Ehlers,
• Jamshed Iqbal and
• Peter Langer

Beilstein J. Org. Chem. 2019, 15, 2830–2839, doi:10.3762/bjoc.15.276

• and NPP3. Absorbance was taken at wavelength of 405 nm as pre-read by using a microplate reader (BioTek FLx800, Instruments, Inc. USA). After pre-read the artificial substrate p-nitrophenyl 5'-thymidine monophosphate (pNP-TMP), 400 µM for NPP1 and 600 µM in case of NPP3, was added followed by a second

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

• Shahien Shahsavari,
• Dhananjani N. A. M. Eriyagama,
• Bhaskar Halami,
• Vagarshak Begoyan,
• Marina Tanasova,
• Jinsen Chen and
• Shiyue Fang

Beilstein J. Org. Chem. 2019, 15, 1116–1128, doi:10.3762/bjoc.15.108

• group and linker still need nucleophilic cleavage. Palladium is expensive and difficult to remove from ODN. Photoirradiation can damage ODNs. The (p-nitrophenyl)ethyl (Npe) and (p-nitrophenyl)ethyloxycarbonyl (Npeoc) groups were also explored for sensitive ODN synthesis under non-nucleophilic conditions

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

Thiol-free chemoenzymatic synthesis of β-ketosulfides

• Adrián A. Heredia,
• Martín G. López-Vidal,
• Marcela Kurina-Sanz,
• Fabricio R. Bisogno and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2019, 15, 378–387, doi:10.3762/bjoc.15.34

• , substrates containing diversely substituted aryl moieties at the α-position of the enol ester, underwent smooth conversion (typically 94–99% except for p-nitrophenyl derivative 1f, for which more enzyme was needed to reach 96%, Table 2, entry 6), regardless the electronic nature of the substituents (see

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• ketone was converted to a trimethylsilyl enol ether upon treatment with KHMDS/Me3SiCl. By contrast, an electron-withdrawing p-nitrophenyl group was not tolerated because the intermediate cyclopropene 65i underwent decomposition under the reaction conditions of the Ireland–Claisen rearrangement

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• polysaccharide mannan, composed of linear α(1→6)-linked, and α(1→2)- and α(1→3)-branched mannopyranosides, and the glycoside p-nitrophenyl α-D-mannopyranoside showed even higher hemagglutination inhibitory potency. These initial experiments let to the assumptions that mycotin is a secreted D-arabinoside- and α-D

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

• Nadia Gruber,
• Jimena E. Díaz and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2018, 14, 2510–2519, doi:10.3762/bjoc.14.227

• acid or other sources of C2 like ethyl orthoformate [52], diarylformamidines [53] or 1,1-dimethoxy-N,N-dimethylmethanamine [17]. Using an alternative approach, the corresponding 2-ABA was treated with acetic anhydride in concentrated sulfuric acid affording 2-methyl-6-nitro-3-(p-nitrophenyl)-3,4-DHQ

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• . Consequently, α-D-mannopyranosides having an aromatic aglycon portion such as p-nitrophenyl α-D-mannopyranoside (1) and the squaric acid derivative 2 [19] (Figure 3) were identified as FimH ligands with relative high affinity (low μmolar range). Based on this knowledge, we proposed the three diazirine-labeled

• from p-nitrophenyl α-D-mannopyranoside (1), which was first reduced to the corresponding amine 6 [26][27] by catalytic hydrogenation (Scheme 1). HATU-mediated peptide coupling with Boc-protected glycine under basic conditions led to 7. After removal of the Boc protecting group using trifluoroacetic

• carbene after extrusion of nitrogen and a crosslinked product after insertion reaction; X = e.g., NH, O, CH2. FimH crystal structure (pdb code 1KLF) with docked p-nitrophenyl α-D-mannopyranoside (1, pNPMan). FimH is a two-domain protein comprising a lectin domain (FimHL) with the carbohydrate binding site

Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis

• Dan Liu,
• Ya-Li Guo,
• Jin Qu and
• Chi Zhang

Beilstein J. Org. Chem. 2018, 14, 1112–1119, doi:10.3762/bjoc.14.97

• the p-nitrophenyl ester method (Scheme 4, method A). The other one was described by Agrigento and co-workers, the cyclization was completed via the p-chlorophenyl thioester method with peptide-thioester being the precursor (Scheme 4, method B) [39]. Herein, we realized the synthesis of pseudostellarin

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• be used to analyze the content of samples withdrawn at suitable intervals. That is why many research groups prefer to use a simpler model, 2-hydroxypropyl p-nitrophenyl phosphate (HPNP; 1, Figure 5), the hydrolysis of which can be followed by UV-spectrophotometry. A lot of useful observations have

• attacking 2´-O−, the KIE is inverted, 16knuc/18knuc = 0.984 ± 0.004 [54]. Both effects are large and consistent with advanced P–O5´ fission and P–O2´ formation in the transition state. For comparison, with uridine 3´-(p-nitrophenyl phosphate), the leaving group KIE expectedly is small, 16klg/18klg = 1.0059

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• buried under those of the host, and cannot be identified). This indicates that the p-nitrophenyl group is allocated in the deshielding region provided by the aryl subunits of the host. Therefore, we can conclude that the aromatic moiety of the guest is specifically included into the cavity, in a quite

• macrocycle cavity. Consequently, the inclusion of the guest forces them in a conformation that is more exposed to the solvent bulk. Finally, taking back to the guest, the inclusion of its p-nitrophenyl group into the cavity implies that the aliphatic moiety protrudes out of the proline-decorated host rim

• subunit. The case of the imidazolium derivative 12 is intriguing, because in principle its 1:1 complex might involve the inclusion of either aromatic ring. However, the preferential inclusion of the p-nitrophenyl group may be reasonably presumed on the grounds of the fact that the complex formed by the

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

• Alena A. Vavilova and
• Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

• between the amide proton and protons of tert-butyl groups, the aromatic protons of the p-nitrophenyl substituent and protons of tert-butyl groups in 2D NOESY NMR spectrum of 1,2-disubstituted compound 6 (see Supporting Information File 1, Figure S15), as well as the cross peaks between the aromatic

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• -urea 36 (78%), bisurea 35 (12%) and o-pda (10%) was isolated, thus contrasting the reactions involving isothiocyanates (Scheme 14a,b). On the other hand, milling mono-urea 36 with one equivalent of p-nitrophenyl isothiocyanate for 30 minutes quantitatively yielded the mixed urea–thiourea 37d. When mono

A direct method for the N-tetraalkylation of azamacrocycles

• Andrew J. Counsell,
• Angus T. Jones,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2016, 12, 2457–2461, doi:10.3762/bjoc.12.239

• ), NaOH (1 M), RCH2Br (4.1 equivalents), rt, 6 h; R = C≡CH (3 and 8), C6H5 (4 and 9), o-bromophenyl (5 and 10), p-nitrophenyl (6 and 11), 2-naphthyl (7 and 12, see Table 1 for yields.). Direct synthesis of N-tetraalkylated macrocycles 3–12 from cyclam (1) and cyclen (2). Supporting Information Supporting

p-Nitrophenyl carbonate promoted ring-opening reactions of DBU and DBN affording lactam carbamates

• Madhuri Vangala and
• Ganesh P Shinde

Beilstein J. Org. Chem. 2016, 12, 2086–2092, doi:10.3762/bjoc.12.197

• towards highly electrophilic p-nitrophenyl carbonate derivatives with ring opening of the bicyclic ring to form corresponding substituted ε-caprolactam and γ-lactam derived carbamates. This simple method presents a unified strategy to synthesize structurally diverse ε-caprolactam and γ-lactam compounds

• with a large substrate scope. Keywords: carbonates; DBN; DBU; lactams; p-nitrophenyl; Introduction Among various organic bases, amidines such as DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and DBN (1,5-diazabicyclo[4.3.0]non-5-ene) having an imino group attached to the α-carbon of the amine are

• behavior of DBU towards imidazolides providing ε-caprolactam-derived carbamates and amides [17]. Here, in this report we present the results obtained by the reaction of DBU and DBN with highly electrophilic p-nitrophenyl carbonates leading to ε-caprolactam and γ-lactam carbamates. p-Nitrophenyl carbonates

Azobenzene-based inhibitors of human carbonic anhydrase II

• Leander Simon Runtsch,
• David Michael Barber,
• Peter Mayer,
• Michael Groll,
• Dirk Trauner and
• Johannes Broichhagen

Beilstein J. Org. Chem. 2015, 11, 1129–1135, doi:10.3762/bjoc.11.127

• bicarbonate and a proton (Figure 1a, left) [1]. Despite its native purpose of pH and pressure regulation, its intrinsic esterase activity can be utilized to measure the catalytic activity by hydrolysis of p-nitrophenyl actetate (pNPA) to a phenolate, of which the product appearance can be observed

Are D-manno-configured Amadori products ligands of the bacterial lectin FimH?

• Tobias-Elias Gloe,
• Insa Stamer,
• Cornelia Hojnik,
• Tanja M. Wrodnigg and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 1096–1104, doi:10.3762/bjoc.11.123

• ]. Obviously, FimH binds α-D-mannosides such as simple methyl α-D-mannoside (MeMan, 1) but not β-mannosides. Mannosides with an aromatic aglycone, such as p-nitrophenyl α-D-mannoside (pNPMan) and 4-methylumbelliferyl α-D-mannoside (3) show an improved affinity to FimH due to π–π-stacking interactions of the

Orthogonal dual-modification of proteins for the engineering of multivalent protein scaffolds

• Michaela Mühlberg,
• Michael G. Hoesl,
• Christian Kuehne,
• Jens Dernedde,
• Nediljko Budisa and
• Christian P. R. Hackenberger

Beilstein J. Org. Chem. 2015, 11, 784–791, doi:10.3762/bjoc.11.88

• ) (see Figure 1). Protein concentrations were checked by UV (λ = 280 nm). Lipase activity test [53]. Lipase activity was determined by measuring the hydrolysis of p-nitrophenyl palmitate (pNPP; Sigma). Solution A (10 mM p-nitrophenyl palmitate in 10 mL ethanol) and solution B (100 mg gummi arabicum in 90