Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

• Jan Szabo,
• Julian Greiner and
• Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

• contrast, the δ(C-5) values vary strongly with the substituent attached to this carbon atom. Whereas the values for 7a–c reflect the different interaction of the phenyl, 3,4,5-trimethoxyphenyl and 4-nitrophenyl substituents with the positive charge density at C-5 through mesomeric and inductive effects

• maximum in the series R = CH3 < phenyl ≈ 3,4,5-trimethoxyphenyl < 4-nitrophenyl. For 7a–c, this absorption band could result from a charge transfer between the amidinate moiety, representing the HOMO of the mesoionic system, and an unoccupied π-orbital of the C(=O)Ar group. Upon N-protonation or N

Regiochemistry of cyclocondensation reactions in the synthesis of polyazaheterocycles

• Patrick T. Campos,
• Leticia V. Rodrigues,
• Andrei L. Belladona,
• Caroline R. Bender,
• Juliana S. Bitencurt,
• Fernanda A. Rosa,
• Davi F. Back,
• Helio G. Bonacorso,
• Nilo Zanatta,
• Clarissa P. Frizzo and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 257–266, doi:10.3762/bjoc.13.29

• , thiophene-2-glyoxylic acid, and N-(2-amino-4-nitrophenyl)acetamide, in accordance with the mechanism proposed in this work. To rationalize why the cyclization reaction between the amidines 8g,h and the α-ketoester did not occur, the HOMO coefficient and charge densities for the nitrogens of the amidine were

Chemical probes for competitive profiling of the quorum sensing signal synthase PqsD of Pseudomonas aeruginosa

• Michaela Prothiwa,
• Dávid Szamosvári,
• Sandra Glasmacher and
• Thomas Böttcher

Beilstein J. Org. Chem. 2016, 12, 2784–2792, doi:10.3762/bjoc.12.277

• modelling and chemical lead optimization. Examples of successful inhibitors are represented by the scaffolds of various 2-benzamidobenzoic acids [11][25][26], 2-nitrophenyl derivatives [27][28][29], ureidothiophene-2-carboxylic acids [24][30], and catechol-based compounds [31]. Many promising in vitro

Thiazol-4-one derivatives from the reaction of monosubstituted thioureas with maleimides: structures and factors determining the selectivity and tautomeric equilibrium in solution

• Alena S. Pankova,
• Pavel R. Golubev,
• Alexander F. Khlebnikov,
• Alexander Yu. Ivanov and
• Mikhail A. Kuznetsov

Beilstein J. Org. Chem. 2016, 12, 2563–2569, doi:10.3762/bjoc.12.251

• it had been done earlier for 3a. On the other hand, heating the solution of thiazolidine 3g up to 120 °C led to coalescence. At this temperature even the signals of the ortho-protons of the 4-nitrophenyl ring (Δδ = 0.9 ppm at −20 °C) coalesced into one (Figure 2). The deviation of the tautomeric

• ratio for 3g from the ones observed for thiazolidines 3a–f seems to be caused by a weakening of the conjugation in the fragment NH–C=N–C=O realized in A form due to the strong electron-withdrawing effect of the 4-nitrophenyl group at the terminal NH group. Introducing an alkyl group in thioureas 1d–f

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

Regiocontroled Pd-catalysed C5-arylation of 3-substituted thiophene derivatives using a bromo-substituent as blocking group

• Mariem Brahim,
• Hamed Ben Ammar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2016, 12, 2197–2203, doi:10.3762/bjoc.12.210

• -substituted thiophenes derivatives containing two different aryl groups at C2 and C5 positions via Suzuki coupling in the second step was also attempted (Scheme 8). The reaction of 5 with phenylboronic acid in the presence of only 1 mol % Pd(OAc)2 catalyst and K2CO3 as base gave 3-methyl-5-(4-nitrophenyl)-2

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

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

• Faith M. Akwi and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186

• experimental domain had no significant effect on the reaction response. For information, this flow rate range covers a residence time of 0.37 to 0.86 minutes. Azo coupling reaction in the synthesis of 4-(2-(4-nitrophenyl)diazenyl)-N-phenylbenzenamine in LTF-MS microreactors The synthesis of azo compounds

• involving couplers containing aminated aromatic systems is usually carried out in slightly acidic reaction conditions. The synthesis of 4-(2-(4-nitrophenyl)diazenyl)-N-phenylbenzenamine was an interesting choice for demonstrating the synthesis of azo compounds involving couplers containing aminated aromatic

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• and 4-nitrophenyl substituted derivatives. All 1,2-oxazines were isolated in high yield (>94%). An asymmetric hetero-Diels–Alder reaction used for the synthesis of (−)-epibatidine was reported by Royer [125][126]. The crucial step of the epibatidine synthesis, proceeding in 64% yield, is based on the

A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

• Dariusz Błachut,
• Joanna Szawkało and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2016, 12, 835–845, doi:10.3762/bjoc.12.82

• %) as a co-solvent with toluene. On the other hand, the attempted coupling of compound 41 with 2-nitrophenylboronic acid and (2-chloro-6-methoxyphenyl)boronic acid failed. Despite more drastic conditions (xylene, DMF, 145 °C, 48 h, 8 mol % Pd(OAc)2/16 mol % S-Phos) any amount of 3,5-bis(2-nitrophenyl

A selective and mild glycosylation method of natural phenolic alcohols

• Mária Mastihubová and
• Monika Poláková

Beilstein J. Org. Chem. 2016, 12, 524–530, doi:10.3762/bjoc.12.51

• organic media or ionic liquids as co-solvents [24][25][26][27]. The enzymatic transglucosylation using 4-nitrophenyl β-D-glucopyranoside as the donor and almond β-glucosidase as biocatalyst gave salidroside (2) in moderate yield [28]. Recently, we have published the enzymatic glycosylation of tyrosol (2

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• )-(−)-enantiomer would be hydrolyzed faster in presence of α-CD. They also studied the alkaline hydrolysis of the two enantiomers of isopropyl para-nitrophenyl methylphosphonate [65] and of isopropyl (S)-2-dimethylaminoethyl methylphosphonothioate [67] in the presence of α-CD at 25 °C. The result indicates that

• the inclusion complexes stereospecific formation is not significant, but that α-CD is predominantly phosphonylated by the (−)-enantiomers. The stereospecificity observed with sarin, isopropyl para-nitrophenyl methylphosphonate and isopropyl (S)-2-dimethylaminoethyl methylphosphonothioate is ascribed

Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene

• Javier Ajenjo,
• Martin Greenhall,
• Camillo Zarantonello and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 192–197, doi:10.3762/bjoc.12.21

• Abstract 3-Fluoro-5-nitro-1-(pentafluorosulfanyl)benzene was prepared by three different ways: as a byproduct of direct fluorination of 1,2-bis(3-nitrophenyl)disulfane, by direct fluorination of 4-nitro-1-(pentafluorosulfanyl)benzene, and by fluorodenitration of 3,5-dinitro-1-(pentafluorosulfanyl)benzene

• byproduct of direct fluorination of 1,2-bis(3-nitrophenyl)disulfane but can be also prepared by other methods, and show that substitution for aromatic fluorine or hydrogen atoms provide a range of novel structurally diverse SF5-benzenes. Results and Discussion Direct fluorination of 1,2-bis(3-nitrophenyl

• -(pentafluorosulfanyl)benzenes. Conversion vs added fluorine equivalents for the fluorination of 1 in MeCN (left) and anhydrous HF (right). Direct fluorination of 1,2-bis(3-nitrophenyl)disulfane. Direct fluorination of 3-nitro-1-(pentafluorosulfanyl)benzene (1). Preparative fluorination of 3-nitro-1

N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd–NHC complexes: synthesis, characterization and catalytic activity in carbon–carbon bond-forming reactions

• Senem Akkoç,
• Yetkin Gök,
• İlhan Özer İlhan and
• Veysel Kayser

Beilstein J. Org. Chem. 2016, 12, 81–88, doi:10.3762/bjoc.12.9

• –NHC complex as catalyst resulted in low yields and conversions (Table 3, entries 9–12). The usage of the morpholinoethyl substituted benzimidazolium compound 4 with Pd(OAc)2 resulted in higher yields of 2-(4-nitrophenyl)benzo[b]thiophene compared to the usage of compounds 1–3. Generally, the PEPPSI Pd

A convenient four-component one-pot strategy toward the synthesis of pyrazolo[3,4-d]pyrimidines

• Mingxing Liu,
• Jiarong Li,
• Hongxin Chai,
• Kai Zhang,
• Deli Yang,
• Qi Zhang and
• Daxin Shi

Beilstein J. Org. Chem. 2015, 11, 2125–2131, doi:10.3762/bjoc.11.229

• -6-(2-nitrophenyl)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine was determined by single crystal X-ray diffraction. Keywords: four-component; one-pot; pyrazolo[3,4-d]pyrimidine; sodium alkoxide; Introduction Heterocycles containing a pyrimidine ring are extensively present in natural products and are very

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

• Cesar Garcias-Morales,
• David Ortegón-Reyna and
• Armando Ariza-Castolo

Beilstein J. Org. Chem. 2015, 11, 1973–1984, doi:10.3762/bjoc.11.213

• acetone–methanol. Yields were 60–80%. The physical and spectroscopic properties of compounds 3–5 are in agreement with previous reports [53][54][55][56]. 2,4-Bis(3-nitrophenyl)-3-azabicyclo[3.3.1]nonan-9-one (6). White solid, Yield: 73%, by using the general procedure 5.10 mmol of cyclohexanone and 10.2

• ), 28.92 (C6, C8), 53.24 (C1, C5), 64.02 (C2-NH, C4-NH), 121.90 (C13, C19), 123.08 (C11, C17) 129.94 (C14, C20), 133.05 (C15, C21), 142.82 (C10, C16), 148.70 (C12-C18), 214.92 (C=O). 1-Methyl-2,4-bis(3-nitrophenyl)-3-azabicyclo[3.3.1]nonan-9-one (7). Yellow solid, Yield: 72%, by using the general procedure

• ), 129.42 (C20), 129.86 (C14), 133.03 (C21), 135.21 (C15), 141.37 (C16) 142.93 (C10), 148.26 (C18), 148.61 (C12), 215.46 (C=O). 1,5-Dimethyl-2,4-bis(3-nitrophenyl)-3-azabicyclo[3.3.1]nonan-9-one (8). White solid, Yield: 64%, by using the general procedure 5.10 mmol of 2,6-dimethylcyclohexanone and 10.2 mmol

Lewis acid-promoted hydrofluorination of alkynyl sulfides to generate α-fluorovinyl thioethers

• Davide Bello and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 1902–1909, doi:10.3762/bjoc.11.205

• the reaction from occurring. Conversely, and as expected, the 4-nitro group had a detrimental effect on the reaction outcome. When 4-nitrophenyl(ethynyl)sulfane (1i) was treated with TiF4, it took nearly 7 days to observe some reaction progress, and the desired Z-isomer of 2i could be isolated in only

• fact that the 4-nitrophenyl group surely must increase the triple bond electrophilicity, hence any trace of water present in the reaction mixture could lead to an intermediate enol thioester which would in turn readily convert to the stable thioester 5. Nonetheless, ensuring rigorously anhydrous

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• was subsequently transformed into a quinolone benzyl ether under reflux conditions. A quinoline triflate ester was prepared from the quinolone and coupled to trimethyl(2-nitrophenyl)stannane by Stille coupling catalyzed by palladium acetate. The afforded nitrophenylquinoline was hydrolyzed and

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• benzenethiols [10][11][12], or by the reaction of nitrophenyl disulfides with elemental fluorine [13][14][15][16]. Aromatic and heteroaromatic SF5 compounds are mostly prepared by the derivatization of commercial nitro-(pentafluorosulfanyl)benzenes [14][17][18][19][20][21][22][23][24][25][26][27] and approaches

Intermolecular addition reactions of N-alkyl-N-chlorosulfonamides to unsaturated compounds

• Gerold Heuger and
• Richard Göttlich

Beilstein J. Org. Chem. 2015, 11, 1226–1234, doi:10.3762/bjoc.11.136

• , 366.0546; Anal. calcd for C15H16NClFO2S (341.834): C, 56.22; H, 5.01; N, 4.10; found, C, 56.43; H, 5.01; N, 4.05. N-[2-Chloro-2-(3-nitrophenyl)ethyl]-N-methylbenzenesulfonamide (6) as a yellow resin. Rf 0.14 (pentane/ether 3:1); 1H NMR (600 MHz, CDCl3) δ 2.43 (s, 3H), 2.69 (s, 3H), 3.50 (dd, J = 14.0, 8.0

Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

• Jerzy Zakrzewski and
• Bogumiła Huras

Beilstein J. Org. Chem. 2015, 11, 1155–1162, doi:10.3762/bjoc.11.130

• , 1163, 984, 827. 2,2,6,6-Tetramethyl-1-oxyl-4-piperidyl 3-E-(2-nitrophenyl)acrylate (5e) 76.4%; mp 107–110 °C; MS (EI, 70 eV, m/z, int [%]) 347 (23, M+), 317 (5), 176 (63, ArCH=CHCO), 154 (25), 140 (11), 139 (17), 130 (61), 124 (100), 109 (87), 102 (21); MS (ESI, m/z, int [%]): 370 (100, M + Na); HRMS

• -nitrophenyl)acrylate (5f) 99.9%; mp 121–123 °C; MS (EI, 70 eV, m/z, int [%]) 347 (5, M+), 176 (85, ArCH=CHCO), 160 (6), 154 (13), 130 (17), 129 (17), 124 (83), 118 (12), 109 (100), 102 (73), 91 (13), 82 (17), 81 (22), 76 (21), 69 (18), 68 (12), 67 (25), 57 (14), 56 (18), 55 (27), 43 (19). 41 (62); MS (ESI, m

• ), 122.63 (CH), 124.74 (CH), 130.16 (CH), 133.85 (CH), 136.32 (C), 142.00 (CH), 148.87 (C), 165.83 (C=O); IR (cm−1, KBr) 3080, 2971, 1709, 1642, 1526, 1358, 1330, 1191, 983, 813, 671. 2,2,6,6-Tetramethyl-1-oxyl-4-piperidyl 3-E-(4-nitrophenyl)acrylate (5g) 55.3%; mp 148–149 °C; MS (EI, 70 eV, m/z, int

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

A new and convenient synthetic way to 2-substituted thieno[2,3-b]indoles

• Roman A. Irgashev,
• Arseny A. Karmatsky,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2015, 11, 1000–1007, doi:10.3762/bjoc.11.112

• -(2-(2-nitrophenyl)-2-oxoethylidene)indolin-2-one (10f): Red crystals; Yield 780 mg (81%); mp 120–121 °C; 1H NMR (400 MHz, DMSO-d6) δ 8.41 (d, J = 7.6 Hz, 1H), 8.21 (dd, J = 8.1, 0.7 Hz, 1H), 7.97–7.82 (m, 3H), 7.52 (td, J = 7.8, 1.0 Hz, 1H), 7.33 (s, 1H), 7.16 (d, J = 7.9 Hz, 1H), 7.11 (td, J = 7.7

• the supplementary crystallographic data for this structure. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/data_request/cif. 8-Ethyl-2-(2-nitrophenyl)-8H-thieno[2,3-b]indole (12f) Yellow powder; Yield 530 mg (82%); mp 103–104 °C

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• the second to the dication. Non-substituted derivative 4c shows a lower first oxidation potential than its alkylS-substituted counterpart 4a,b, as expected due to the electron-withdrawing effect of the two thioalkyl groups [28][29]. The strong electron-withdrawing effect of the 4-nitrophenyl group in

• ; CV (vs SCE, CH2Cl2): E1/2ox1 = 0.48 V, E1/2ox2 = 0.83 V. 2-[4,5-Bis(propylthio)-1,3-dithiol-2-ylidene]-5-(4-nitrophenyl)-5H-1,3-dithiolo[4,5-c]pyrrole (4d). Prepared from 7a (0.055 g, 0.140 mmol), CuI (0.014 g, 0.070 mmol), K3PO4 (0.089 g, 0.42 mmol), trans-diaminocyclohexane (7.5 µL, 0.062 mmol) and