Direct access to pyrido/pyrrolo[2,1-b]quinazolin-9(1H)-ones through silver-mediated intramolecular alkyne hydroamination reactions

• Hengshuai Wang,
• Shengchao Jiao,
• Kerong Chen,
• Xu Zhang,
• Linxiang Zhao,
• Dan Liu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 416–424, doi:10.3762/bjoc.11.47

• ), deoxyvasicinone was subjected to a free-radical bromination using NBS and the subsequent treatment with NaOAc/AcOH as an acetoxylation reagent [12]. However, for most of these synthetic strategies harsh reaction conditions are a necessity, produce unstable sulfonamide anhydride intermediates [2][13], which are

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• reported that 4-amino-2-sulfanylphenol derivatives display highly specific protein kinase and angiogenesis inhibitory activities. Based on their previous findings, the structure of compound 24 was optimized by replacing the naphthalene by a phenolic skeleton and a sulfonamide fragment [52]. These compounds

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• . For comparison, we also synthesized and tested a bromine modified dansyl derivative N-(3-azidopropyl)-6-bromo-5-(dimethylamino)naphthalene-1-sulfonamide (BNS, 6, Figure 2). Dansyl chloride is brominated according to the literature [30] to produce 6-bromo-5-(dimethylamino)naphthalene-1-sulfonyl

• yield and compared it with other commercially available fluorophores of similar size (Figure 2). We chose N-(3-azidopropyl)-5-(dimethylamino)naphthalene-1-sulfonamide (DNS, 8) with a fluorophore system exhibiting a large stokes shift [1] suitable for fluorescence detection with UV filters

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• converted to the corresponding sulfonamide with para-methoxyphenyl (PMP) sulfonyl chloride. Cleavage of the silyl ether moiety with TBAF gave primary alcohol 143, which was oxidized to the corresponding acid 144 by a two-step protocol consisting of treatment with Dess–Martin periodinane followed by Pinnick

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• must be activated as a sulfonamide (or acetamide) to produce the expected phosphoramidate [42]. The authors, who used a phase-transfer agent, postulated that this activation resulted from the increase of the acidity of the N–H bond despite the evident reduction of the nucleophilic character (Scheme 14

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

A new manganese-mediated, cobalt-catalyzed three-component synthesis of (diarylmethyl)sulfonamides

• Antoine Pignon,
• Erwan Le Gall and
• Thierry Martens

Beilstein J. Org. Chem. 2014, 10, 425–431, doi:10.3762/bjoc.10.39

• vigorous (~500 rpm) stirring, and the mixture was heated to 60 °C. After cooling to room temperature, the organic bromide 3 (7.5 mmol), the aldehyde 2 (2.5 mmol), the sulfonamide 1 (2.5 mmol), and cobalt bromide (0.25 g, 1.125 mmol) were added successively, and the resulting mixture was stirred for 10

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• method to alternative sulfonamide based diepoxides, focusing on one characteristic example. Furthermore, the polymerization of these types of diepoxides was investigated with lysine-based α-amino-ε-caprolactam through rheological measurements. Results and Discussion N,N'-(Hexane-1,6-diyl)bis(4

• -methylbenzenesulfonamide) (3), as precursor for the subsequent N-alkylation and further Prilezhaev epoxidation, was synthesized easily from p-toluenesulfonyl chloride (1) and hexamethylenediamine (2) [23]. The resulting crystalline sulfonamide was first described in 1927 prepared from 1,6-dibromohexane and p

• route for the synthesis of N,N'-(hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide) (6) via N-alkylation of N,N'-(hexane-1,6-diyl)bis(4-methylbenzenesulfonamide) (3) and further oxidation was described. For the first time, the CD-mediated N-alkylation of a sulfonamide was conducted

Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates

• Christina Lohoelter,
• Malte Brutschy,
• Daniel Lubczyk and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317

• crystal microbalances. Based on the reported triamine all-syn-2a [40], 2a was brought to reaction with para-toluenesulfonyl chloride in order to equip the receptor scaffold with sulfonamide binding sites (Scheme 1). The reaction proceeds with a moderate yield of 32% under very mild reaction conditions

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• , sulfonamide and amine substituents. The catalytic process is insensitive towards the presence of air and pH changes between pH 4 and 12 in a solvent mixture of water and tert-butanol. This strictly regioselective stepwise process gives the 1,4-disubstituted 1,2,3-triazole only and accelerates the reaction by

Multigramme synthesis and asymmetric dihydroxylation of a 4-fluorobut-2E-enoate

• James A. B. Laurenson,
• John A. Parkinson,
• Jonathan M. Percy,
• Giuseppe Rinaudo and
• Ricard Roig

Beilstein J. Org. Chem. 2013, 9, 2660–2668, doi:10.3762/bjoc.9.301

• sulfonamide which can accelerate hydrolysis and catalytic turnover was also added to the reaction mixtures [26]. Yields for the dihydroxylation chemistry were variable (44–80%); even though they are diols, these small molecules proved volatile. Reproducible yields (>55%) could be achieved if care was taken

Cyclopamine analogs bearing exocyclic methylenes are highly potent and acid-stable inhibitors of hedgehog signaling

• Johann Moschner,
• Anna Chentsova,
• Nicole Eilert,
• Irene Rovardi,
• Philipp Heretsch and
• Athanassios Giannis

Beilstein J. Org. Chem. 2013, 9, 2328–2335, doi:10.3762/bjoc.9.267

• employing the Peterson protocol (TMSCH2CeCl2, THF, −78 °C; then TMEDA; then HF, MeCN, 25 °C, 64%) [36]. Towards this end the azide moiety was reduced and monoprotection of the so-obtained amine as a sulfonamide (LiAlH4, THF, 0 °C→25 °C; then benzenesulfonyl chloride, Et3N, DMF, 0 °C, 69%) gave 17

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• a double nucleophilic substitution between tosylamine and 2,3-bis-chloromethylpyridine (1.112) followed by catalytic reduction of the resulting bicycle using palladium on carbon in acetic acid (Scheme 20). As the corresponding sulfonamide 1.113 was found to be a crystalline solid a resolution using

The chemistry of amine radical cations produced by visible light photoredox catalysis

• Jie Hu,
• Jiang Wang,
• Theresa H. Nguyen and
• Nan Zheng

Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234

• tetrahydroimidazoles 72 based on intramolecular interception of the iminium ions by a tethered sulfonamide (71, Scheme 18) [86]. Ru(bpy)3Cl2 was employed as the photocatalyst with oxygen as the stoichiometric oxidant. The use of a base in an alcohol solvent, such as MeOH, was also the key to the success of this

• solvent. No external base was needed when the alcohol was the nucleophile. However, if the sulfonamide was the nucleophile, an external base such as t-BuOK was required presumably to increase the nucleophilicity of the sulfonamide. The Rueping group trapped the iminium ions using phosphites 76 to produce

Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

• Robert J. Perkins,
• Hai-Chao Xu,
• John M. Campbell and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2013, 9, 1630–1636, doi:10.3762/bjoc.9.186

• electron-rich olefin was coupled to one of two competing nucleophiles, a sulfonamide and an alcohol (5). When the oxidation was run with 2,6-lutidine as a base (not shown), the reaction led to the formation of a radical cation from the electron-rich olefin followed by trapping by the alcohol nucleophile to

• form product 9. No product from sulfonamide trapping (8) was observed. However, when the reaction was run under more basic conditions (0.5 equivalents of lithium methoxide) cyclic voltammetry data indicated that the oxidative cyclizations were initiated by the oxidation of sulfonamide anion. This led

• to initial formation of N-localized radical 6. Depending on the reaction conditions, the experiment favoured either a sulfonamide or alcohol based cyclization. Density functional theory (DFT) calculations suggested that sulfonamide based cyclizations proceed by addition of the N-localized radical to

Gold-catalyzed intermolecular hydroamination of allenes with sulfonamides

• Chen Zhang,
• Shao-Qiao Zhang,
• Hua-Jun Cai and
• Dong-Mei Cui

Beilstein J. Org. Chem. 2013, 9, 1045–1050, doi:10.3762/bjoc.9.117

• ; hydroamination; N-sulfonyl; selectivity; sulfonamide; Introduction Hydroamination of an N–H bond across a C–C unsaturated bond represents one of the most effective and atom-economical methods to prepare amine derivatives [1][2][3][4][5]. In the case of using allenes, this reaction can lead to allylamines, which

• 3e in 54 and 72% yields, respectively (Table 2, entries 4–5). Under the same reaction conditions, the hydroamination of aliphatic sulfonamides took place smoothly to afford the corresponding N-allylic sulfonamide 3f with 56% yield (Table 2, entry 6). We also used N-substituted sulfonamide 2g as the

• aliphatic allene 1e formed a 71:29 mixture of linear product (3ka) and branch product (3kb) under the same conditions (Table 3, entry 4). Furthermore, disubstituted allenes also worked well. Differentially 1,1-disubstituted allene 1f reacted with sulfonamide to afford trans-adducts 3l with high selectivity

Use of 3-[¹⁸F]fluoropropanesulfonyl chloride as a prosthetic agent for the radiolabelling of amines: Investigation of precursor molecules, labelling conditions and enzymatic stability of the corresponding sulfonamides

• Reik Löser,
• Steffen Fischer,
• Achim Hiller,
• Martin Köckerling,
• Uta Funke,
• Aurélie Maisonial,
• Peter Brust and
• Jörg Steinbach

Beilstein J. Org. Chem. 2013, 9, 1002–1011, doi:10.3762/bjoc.9.115

• hydrolytic cleavage [15][16][17]. As an alternative to acyl-based prosthetic groups the 3-[18F]fluoropropanesulfonyl group introduced by Li et al. attracted our interest [18]. Labelling with radiofluorine by sulfonamide formation seems to be intriguing not only because of the inertness against the metabolic

• product 18. This compound was obtained in the form of crystals suitable for X-ray diffraction analysis. The molecular structure of 18 is shown in Figure 2A, confirming unambiguously its identity as N-(4-nitrophenyl)-3-fluoropropane-1-sulfonamide. Crystal data and structure refinement parameters are

• be also observed for the molecular structure of 18 in the crystal. This is indicated by the fact that the sum of the three valence angles around the sulfonamide nitrogen (C4–N1–S1, C4–N1–H1C, and S1–N1–H1C) is equal to 348(4)°, which is significantly less than 360° for trigonal planar geometry

Preparation and ring-opening reactions of N-diphenylphosphinyl vinyl aziridines

• Ashley N. Jarvis,
• Andrew B. McLaren,
• Helen M. I. Osborn and
• Joseph Sweeney

Beilstein J. Org. Chem. 2013, 9, 852–859, doi:10.3762/bjoc.9.98

• ]. However, a key limitation to the synthetic application of aziridines in general is the nature of the N-substituent: most synthetic routes to aziridines deliver N-sulfonylated products, and the cleavage of the sulfonamide bond is often challenging. Perhaps for this reason, and despite the plethora of

Synthesis of skeletally diverse alkaloid-like molecules: exploitation of metathesis substrates assembled from triplets of building blocks

• Sushil K. Maurya,
• Mark Dow,
• Stuart Warriner and
• Adam Nelson

Beilstein J. Org. Chem. 2013, 9, 775–785, doi:10.3762/bjoc.9.88

• with methyl chloroformate and DMAP. The allylic carbonate 15 underwent efficient asymmetric allylic amination [20] with o-nitrophenylsulfonamide as the nucleophile to give the allylic sulfonamide 17 in 66% yield; in addition, the linear product 16 was also obtained in 7% yield. Desilylation of 17 (→ 18

Regio- and stereoselective carbometallation reactions of N-alkynylamides and sulfonamides

• Yury Minko,
• Morgane Pasco,
• Helena Chechik and
• Ilan Marek

Beilstein J. Org. Chem. 2013, 9, 526–532, doi:10.3762/bjoc.9.57

• give 3c (Table 1, entry 3). Although N-heterosubstituted alkynes were used in all cases, the α-isomer is regioselectively obtained, as confirmed by 1H NMR analysis of the crude reaction mixture after hydrolysis, through an intramolecular chelation between the N-sulfonamide moiety and the organocopper

Facile synthesis of benzothiadiazine 1,1-dioxides, a precursor of RSV inhibitors, by tandem amidation/intramolecular aza-Wittig reaction

• Krishna C. Majumdar and
• Sintu Ganai

Beilstein J. Org. Chem. 2013, 9, 503–509, doi:10.3762/bjoc.9.54

• chloride followed by the reaction with appropriate amines to give the requisite 2-azido-N-substituted benzenesulfonamides 10a–i. The sulfonamide 10b was reacted with ethyl carbonochloridate to afford the corresponding amide derivative 9b required for our study. Initially, we turned our attention to the

• heating the sulfonamide 10b with ethyl carbonochloridate, Et3N and PPh3 in DCB at 135 °C for 6 h, which gave the cyclized product 13b in 78% yield (Table 2, entry 1). The base Et3N was then replaced by Cs2CO3 or K2CO3, but no better result was obtained (Table 2, entries 2 and 3). Only DIPEA gave 69% yield

• SO2NH2 by the reaction of nucleophilic sulfonamide 10 with ethyl carbonochloridate in the presence of Et3N to form the intermediates 9, which may then undergo intramolecular aza-Wittig reaction via the formation of iminophosphorane intermediate I. We isolated iminophosphorane intermediate 12b from the

Iridium-catalyzed intramolecular [4 + 2] cycloadditions of alkynyl halides

• Andrew Tigchelaar and
• William Tam

Beilstein J. Org. Chem. 2012, 8, 1765–1770, doi:10.3762/bjoc.8.201

• ). Deprotonation of 8 with sodium hydride, followed by trapping with propargyl bromide provided 9 in 60% yield, and a Mitsunobu reaction between 8 and sulfonamide 10 (prepared as per reference [47]) provided 11 in 74% yield. Bromination of 9 and 11 provided diene-tethered alkynyl halides 1c (57%) and 1e (83

Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

• Marcus Frings,
• Isabelle Thomé and
• Carsten Bolm

Beilstein J. Org. Chem. 2012, 8, 1443–1451, doi:10.3762/bjoc.8.164

• thiourea or sulfonamide unit, and the second relates to the activation of the alcohol by the basic nitrogen of the amine. Which effect dominates in the case of (S)-3 – a carbonyl activation by a single hydrogen bond or an enhancement of the alcohol activity by the weakly basic sulfoximine nitrogen

Asymmetric organocatalytic decarboxylative Mannich reaction using β-keto acids: A new protocol for the synthesis of chiral β-amino ketones

• Chunhui Jiang,
• Fangrui Zhong and
• Yixin Lu

Beilstein J. Org. Chem. 2012, 8, 1279–1283, doi:10.3762/bjoc.8.144

• , entry 1). Quinine-derived sulfonamide [40], β-isocupreidine (β-ICD) [41][42] and biscinchona alkaloid (DHQ)2AQN were all found to be poor catalysts (Table 1, entries 2–4). On the other hand, cinchona alkaloid derived bifunctional thiourea tertiary amine catalysts afforded much improved results (Table 1

Synthesis and characterization of Sant-75 derivatives as Hedgehog-pathway inhibitors

• Chao Che,
• Song Li,
• Bo Yang,
• Shengchang Xin,
• Zhixiong Yu,
• Taofeng Shao,
• Chuanye Tao,
• Shuo Lin and
• Zhen Yang

Beilstein J. Org. Chem. 2012, 8, 841–849, doi:10.3762/bjoc.8.94

• [39][40]. It is noteworthy that some polar groups, including amino, hydroxy and sulfonamide, could not tolerate the conditions of Higa cyclization, and had to be introduced through transformation reactions after the N-acylation step. As depicted in Scheme 3, NH2-derivative 7m was prepared from the NO2