Efficient Cu-catalyzed base-free C–S coupling under conventional and microwave heating. A simple access to S-heterocycles and sulfides

• Silvia M. Soria-Castro and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2013, 9, 467–475, doi:10.3762/bjoc.9.50

• -proline, benzotriazole, tetramethylethylenediamine (TMEDA), dimethylethylenediamine (DMEDA), and acetylacetone, under the optimized reaction conditions with 1,10-phenanthroline (Table 1, entry 9). These ligands, with different coordinating and structural properties, gave no positive results, and PhI was

Chemical modification allows phallotoxins and amatoxins to be used as tools in cell biology

• Jan Anderl,
• Hartmut Echner and
• Heinz Faulstich

Beilstein J. Org. Chem. 2012, 8, 2072–2084, doi:10.3762/bjoc.8.233

• coupling reagent 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoborate (TBTU) and 2 equiv of diisopropylethylamine (DIEA) over the resin loading. Before the coupling steps the Fmoc groups were removed from the last amino acid of the growing peptide fragment by using 25% piperidine in

Partial thioamide scan on the lipopeptaibiotic trichogin GA IV. Effects on folding and bioactivity

• Marta De Zotti,
• Barbara Biondi,
• Cristina Peggion,
• Matteo De Poli,
• Haleh Fathi,
• Simona Oancea,
• Claudio Toniolo and
• Fernando Formaggio

Beilstein J. Org. Chem. 2012, 8, 1161–1171, doi:10.3762/bjoc.8.129

• of the 1–8 and the thionated 9–11 segments. For the difficult coupling steps, in particular those involving the segment condensations, the N-[3-(dimethylamino)-propyl]-N'-ethylcarbodiimide (EDC)/7-aza-1-hydroxy-1,2,3-benzotriazole (HOAt) [51] activating method was used, while the EDC/1-hydroxy-1,2,3

• -benzotriazole (HOBt) [52] method turned out to be appropriate for the formation of the other peptide bonds. The yields of the segment condensation reactions were good (75–83%). An important feature, which makes trichogin GA IV a versatile synthetic platform, is the presence of as many as seven achiral (Aib or

Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

• Workalemahu M. Berhanu,
• Mohamed A. Ibrahim,
• Girinath G. Pillai,
• Alexander A. Oliferenko,
• Levan Khelashvili,
• Farukh Jabeen,
• Bushra Mirza,
• Farzana Latif Ansari,
• Ihsan ul-Haq,
• Said A. El-Feky and
• Alan R. Katritzky

Beilstein J. Org. Chem. 2012, 8, 1146–1160, doi:10.3762/bjoc.8.128

• activity, with compounds 24 and 27 being the most active. The side-chain substitution clearly controls the antibacterial activity, as the cyclic scaffold is identical. The 18-membered ring scaffold 37, accessible through the benzotriazole route, provides an excellent opportunity for introducing

• economic synthetic route, renders scaffold 37 as a promising platform for further rational drug design. Synthesis Treatment of dicarboxylic acids 34a–c by a standard method [36] using thionyl chloride and 1H-benzotriazole gave the corresponding benzotriazole derivatives in 37–54% yield (Scheme 1, see

• further application of this synthetic approach 35 was coupled with 2 equiv of L-Phe-OH in the presence of TEA in aqueous acetonitrile at room temperature over 3 h giving the bis N-acylated compound 38 in 88% yield. Compound 38 was converted to the corresponding benzotriazole derivative 39 and coupled with

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

• Zhiyuan Ma,
• Feng Ni,
• Grace H. C. Woo,
• Sie-Mun Lo,
• Philip M. Roveto,
• Scott E. Schaus and
• John K. Snyder

Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93

• -carboline by Robinson in 1924 [15][36] proceeded through the acid-catalyzed decomposition of 1-(2-pyridyl)benzotriazole, a modification of the Graebe–Ullmann carbazole synthesis, which closes the indole ring. This procedure was improved upon and exploited for decades [37][38][39][40]. Later, reversing the

Chemistry of polyhalogenated nitrobutadienes, 10: Synthesis of highly functionalized heterocycles with a rigid 6-amino-3-azabicyclo[3.1.0]hexane moiety

• Viktor A. Zapol’skii,
• Jan C. Namyslo,
• Armin de Meijere and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2012, 8, 621–628, doi:10.3762/bjoc.8.69

• -dimensional, direct detection) and an inverse-detected 1H/15N-HMBC gave the nitrogen shifts (internal MeNO2 at 0.0 ppm): −65.8 ppm (C=N), −244.2 ppm (NCO), and −319.5 ppm (NBn). In addition to the twofold triazole substitution, the nitrodiene 3 was treated with four equiv of benzotriazole in THF. Thus, the

• have tautomerized to a pyridin-2(1H)-imine derivative, which then underwent cyclization by a formal nucleophilic substitution leading to the 4H-pyrido[1,2-a]pyrimidine 23. The remaining benzotriazole group in 23, which is activated by the adjacent nitro substituent allows for a further nucleophilic

• 75–90% yield (Scheme 6). A conceivable mechanism for the cascade reaction that leads to the pyrazoles 27 and 28 is presented in Scheme 7. Initially, the trichlorobutene I is formed upon addition of the arylhydrazine to the nitro-substituted butadiene 25. Subsequent elimination of benzotriazole

Synthesis of szentiamide, a depsipeptide from entomopathogenic Xenorhabdus szentirmaii with activity against Plasmodium falciparum

• Friederike I. Nollmann,
• Andrea Dowling,
• Marcel Kaiser,
• Klaus Deckmann,
• Sabine Grösch,
• Richard ffrench-Constant and
• Helge B. Bode

Beilstein J. Org. Chem. 2012, 8, 528–533, doi:10.3762/bjoc.8.60

• resin was used in order to avoid nonspecific interaction in the cyclization process. Prior to the synthesis, the resin was reactivated [15] and then loaded with Fmoc-L-Tyr(t-Bu)-OH [16], followed by the build-up of the linear sequence 3 (Scheme 2) with O-benzotriazole-N,N,N’,N’-tetramethyluronium

• /Carbolution Chemicals; c = 0.2 mol/L) was activated in situ with 5 equiv O-benzotriazole-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HBTU; Iris Biotech) in dimethylformamide (DMF; Acros Organics, Belgium; c = 0.5 mol/L) in the presence of 10 equiv N,N-diisopropylethylamine (DIEA; Novabiochem, Darmstadt

Synthesis and oxidation of some azole-containing thioethers

• Andrei S. Potapov,
• Nina P. Chernova,
• Vladimir D. Ogorodnikov,
• Tatiana V. Petrenko and
• Andrei I. Khlebnikov

Beilstein J. Org. Chem. 2011, 7, 1526–1532, doi:10.3762/bjoc.7.179

• Akademicheskii Ave., 634055 Tomsk, Russia 10.3762/bjoc.7.179 Abstract Pyrazole and benzotriazole-containing thioethers, namely 1,5-bis(3,5-dimethylpyrazol-1-yl)-3-thiapentane, 1,8-bis(3,5-dimethylpyrazol-1-yl)-3,6-dithiaoctane and 1,3-bis(1,2,3-benzotriazol-1-yl)-2-thiapropane were prepared and fully

• characterized. Oxidation of the pyrazole-containing thioether by hydrogen peroxide proceeds selectively to provide a sulfoxide or sulfone, depending on the amount of oxidant used. Oxidation of the benzotriazole derivative by hydrogen peroxide is not selective, and sulfoxide and sulfone form concurrently

• . Selenium dioxide-catalyzed oxidation of benzotriazole thioether by H2O2, however, proceeds selectively and yields sulfoxide only. Keywords: azole; oxidation; sulfone; sulfoxide; thioether; Introduction Compounds comprising two pyrazole moieties linked by an aliphatic spacer act as bidentate chelating

Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements

• Dawei Wang,
• Yanwei Zhang,
• Rong Cai and
• Xiaodong Shi

Beilstein J. Org. Chem. 2011, 7, 1014–1020, doi:10.3762/bjoc.7.115

• –Au-2 was prepared either from the addition of HOTf to TA–Au-1 or by the reaction between PPh3Au–OTf (prepared from PPh3–Au–Cl and AgOTf) and benzotriazole. Both complexes were stable and could be further purified by recrystallization to ensure no extra Ag+ or acid in the catalysts. The crystal

Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• acid were purchased from Yangzhou Baosheng Bio-Chemical Co. Ltd. N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDCI), 4-dimethylaminopyridine and 1-hydroxy benzotriazole were purchased from Shanghai Medpep Co. Ltd. 1-Dodecanol and solvents were purchased from Sinopharm Chemical Reagent

Synthesis of some novel hydrazono acyclic nucleoside analogues

• Mohammad N. Soltani Rad,
• Ali Khalafi-Nezhad and
• Somayeh Behrouz

Beilstein J. Org. Chem. 2010, 6, No. 49, doi:10.3762/bjoc.6.49

• derivatives were conducted according to Scheme 1. As shown in Scheme 1, condensation of imidazole, 2-phenylimidazole, hydantoin, benzimidazole and benzotriazole with 2-bromoacetophenone and 4′-methoxy-2-bromoacetophenone gave the key intermediates, ketones 1a–1g. Based on our literature survey, we recognized