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

• University Munich and Munich Center for Integrated Protein Science, Lichtenbergstr. 4, 85748 Garching, Germany 10.3762/bjoc.11.127 Abstract Aryl sulfonamides are a widely used drug class for the inhibition of carbonic anhydrases. In the context of our program of photochromic pharmacophores we were

• interested in the exploration of azobenzene-containing sulfonamides to block the catalytic activity of human carbonic anhydrase II (hCAII). Herein, we report the synthesis and in vitro evaluation of a small library of nine photochromic sulfonamides towards hCAII. All molecules are azobenzene-4-sulfonamides

• , that leads to blindness, is achieved with the application of aryl sulfonamides [3]. Being a transition-state analogue [4], this functional group exhibits excellent blocking characteristics of hCAII and culminates its power in many modern marketed drugs, such as acetazolamide (AAZ) or dorzolamide

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• and co-workers developed various N-sulfinyl homoallylic amines (76) [160] and N-cinnamyl sulfonamides (77) [161] ligands for the rhodium-catalyzed asymmetric 1,4-arylation of a variety of α,β-unsaturated carbonyl compounds. Finally, in 2012, Franzén and co-workers designed an indole-olefin-oxazoline

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

• Antoine Pignon Erwan Le Gall Thierry Martens Électrochimie et Synthèse Organique, Institut de Chimie et des Matériaux Paris-Est, UMR 7182 CNRS, Université Paris-Est Créteil, 2-8 rue Henri Dunant, 94320 Thiais, France 10.3762/bjoc.10.39 Abstract The synthesis of (diarylmethyl)sulfonamides and

• related compounds by a new manganese-mediated, cobalt-catalyzed three-component reaction between sulfonamides, carbonyl compounds and organic bromides is described. This organometallic Mannich-like process allows the formation of the coupling products within minutes at room temperature. A possible

• mechanism, emphasizing the crucial role of manganese is proposed. Keywords: carbonyl compounds; cobalt; manganese; multicomponent reaction; organic bromides; sulfonamides; Introduction (Diarylmethyl)amines constitute an important class of pharmacologically active compounds, displaying e.g. antihistaminic

New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

• Helge Klare,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2014, 10, 224–236, doi:10.3762/bjoc.10.18

• , e.g. sulfonamides [12], urea-N-sulfoxides [13], guanines [14] as well as protonated catalysts such as ammonium [15], 2-aminopyridinium [16] and guanidinium [17] motifs. Most catalysts can form two hydrogen bonds to a reactant, which further enhances their ability to activate and constrain it to a

Diversity-oriented synthesis of dihydrobenzoxazepinones by coupling the Ugi multicomponent reaction with a Mitsunobu cyclization

• Lisa Moni,
• Luca Banfi,
• Andrea Basso,
• Alice Brambilla and
• Renata Riva

Beilstein J. Org. Chem. 2014, 10, 209–212, doi:10.3762/bjoc.10.16

• reactions [2], especially the intramolecular Mitsunobu reaction of alcohols with phenols or sulfonamides. By exploiting a single post-MCR transformation (the Mitsunobu reaction) it is possible to obtain several diverse heterocyclic scaffolds by installing the two additional groups in any of the four

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

• ; rheology; sulfonamides; Introduction Various diepoxides easily react with amines or diamines to form cross-linked, cyclic or linear addition-polymers, which are implemented in construction, electronic, aerospace, medical and dental industries [1][2]. Hereby, bisphenol A diglycidyl ether (BADGE) is often

• [16][17][18]. To our best knowledge, CD mediated N-alkylation of sulfonamides is not yet described. Generally, only a few examples are known in literature about CD assisted alkylation of amines in aqueous solution [19][20][21][22]. Hence, in this work, we wish to present our direct and CD mediated

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

• Triphenylene ketals The high hydrogen bonding donor capability of sulfonamides made this class of functional groups highly attractive for supramolecular affinity materials [60]. The installation of larger substituents at the sulfonyl moiety should provide suitable properties for the processing on the quartz

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• addition of carbamates, sulfonamides and imidazolidinones to linear and cyclic dienes 17 in the presence of catalytic amounts of PPh3AuOTf (Scheme 6). The method featured excellent 1,2-regioselectivity and high chemoselectivity, providing protected allylamines 18, in good yields, using nearly equimolar

• extended to amide-based nucleophiles exploiting similar operational conditions [39]. After these seminal works the scope of gold-catalyzed hydroamination of olefins was extend to other classes of nitrogen nucleophiles. Sulfonamides were successfully employed in the intra- and intermolecular hydroamination

• of alkenes catalyzed by Ph3PAuOTf (toluene, 85 °C, Scheme 8) [40]. In particular, primary and secondary sulfonamides reacted smoothly with mono and disubstituted alkenes delivering nitrogen compounds 22 and 23 with Markovnikov regioselectivity (Scheme 8a). Moreover, N-protected pyrrolidines 24 and 25

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

• Marvin group reported an identical synthesis of isoquino[2,1-a][3,1]oxazine using Ru(bpy)3Cl2 instead [88]. The tethered nucleophiles, primary alcohols or sulfonamides, are part of the N-aryl group of tetrahydroisoquinolines 73. Similar to the synthesis of tetrahydroimidazoles 72, MeOH was the optimal

• amides. Intramolecular interception of iminium ions by sulfonamides. Intramolecular interception of iminium ions by alcohols and sulfonamides. Intermolecular interception of iminium ions by phosphites. Photoredox-catalyzed oxidative phosphonylation by Eosin Y. Conjugated addition of α-amino radicals to

Re₂O₇-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

• Wantanee Sittiwong,
• Michael W. Richardson,
• Charles E. Schiaffo,
• Thomas J. Fisher and
• Patrick H. Dussault

Beilstein J. Org. Chem. 2013, 9, 1526–1532, doi:10.3762/bjoc.9.174

• require relatively high temperatures [28][29][30]. Our results suggest that amines and amides actively suppress the ability of Re(VII)-oxides to activate alcohols. We note, however, a recent report by Ghorai describing the allylation of iminium ions generated from aldehydes and sulfonamides in the

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

• the intermolecular hydroamination of allenes with sulfonamides is shown. The reaction proceeded smoothly under mild conditions for differently substituted allenes giving N-allylic sulfonamides in good yields with high regioselectivity and E-selectivity. Keywords: allene; gold catalysis

• hydroamination, many require extreme and extended reaction conditions. Thus, development of these reactions is still needed. Recently, Yamamoto and co-workers reported the Pd(0)-catalyzed intermolecular hydroamination of allenes with sulfonamides [25]. In this paper, we wish to develop a gold(I)-complex

• -catalyzed addition of sulfonamides as the amine partner to allenes to synthesize N-allylic sulfonamides with high regio- and stereoselectivity. Results and Discussion As part of our ongoing studies on metal-catalyzed reactions, we have reported the hydroalkoxylation of allenes with alcohols and

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

• sulfonamides was confirmed chromatographically by comparison with their nonradioactive counterparts. Even for weakly nucleophilic amines such as 4-nitroaniline the desired radiolabelled sulfonamides were accessible in satisfactory yields owing to systematic variation of the reaction conditions. With respect to

• of the analogous fluoroacetamide. Keywords: fluorine-18; hydrolytic metabolism; prosthetic groups; radiochemistry; sulfonamides; Introduction The importance of molecular imaging, i.e., the characterisation and measurement of biological processes in living organisms at the molecular level using

• desired intermediate was purified by vacuum distillation or transformed as crude product to the final 3-fluoropropanesulfonamides, as shown for compound 11. Alternatively, 10 was obtained commercially. The reaction of 10 with aliphatic amines proceeded quantitatively and smoothly to the sulfonamides 12–15

Appel-reagent-mediated transformation of glycosyl hemiacetal derivatives into thioglycosides and glycosyl thiols

• Tamashree Ghosh,
• Abhishek Santra and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2013, 9, 974–982, doi:10.3762/bjoc.9.112

• preparation of several glycosyl donors such as thioglycosides [33][34], glycosyl sulfenamides [35] and sulfonamides [36], glycosyl disulfides [37], glycosyl thionolactones [38], etc. A number of reports are available for the preparation of glycosyl thiols, which include (a) a two-step reaction of glycosyl

Enantioselective reduction of ketoimines promoted by easily available (S)-proline derivatives

• Martina Bonsignore,
• Maurizio Benaglia,
• Laura Raimondi,
• Manuel Orlandi and
• Giuseppe Celentano

Beilstein J. Org. Chem. 2013, 9, 633–640, doi:10.3762/bjoc.9.71

• -established methodology to perform enantioselective reductions of carbon nitrogen double bonds [1]. In the past decade different classes of enantiomerically pure Lewis bases have been developed, including N-formyl derivatives, oxazolines, imidazole derivatives, sulfonamides and picolinamides [2][3]. Some of

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

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

• ] and sulfonamides [49]. Thioacetate and thiobenzoate derivatives have been synthesized by the reactions of thioacetate and thiobenzoate anions with arenediazonium tetrafluoroborates [50]. However, this methodology implies moderate overall yields and the handling of usually unstable diazonium salts

Acylsulfonamide safety-catch linker: promise and limitations for solid–phase oligosaccharide synthesis

• Jian Yin,
• Steffen Eller,
• Mayeul Collot and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 2067–2071, doi:10.3762/bjoc.8.232

• glycosylated linker 21 (major product) rather than the desired product 22 were found (Scheme 3). N-Glycosidic sulfonamides were previously used during the synthesis of inhibitors of hepatocellular carcinoma cells [26]. This observation illustrates a limitation of the linker system since these undesired

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

• was known for chiral bifunctional amine-based sulfonamides that two hydrogen bond donors were not strictly required in the enantioselective organocatalytic ring opening of meso-anhydrides [48][54], this particular transformation was chosen as initial test reaction. Cyclic anhydride 4 served as

• good yield (66%) within 24 h. Disappointingly, however, the product was racemic. In general, two concomitant events are discussed for bifunctional organocatalysts such as amino group-containing sulfonamides or thioureas: One is the activation of the anhydride carbonyl group by hydrogen bonding to the

Exploring chemical diversity via a modular reaction pairing strategy

• Joanna K. Loh,
• Sun Young Yoon,
• Thiwanka B. Samarakoon,
• Alan Rolfe,
• Patrick Porubsky,
• Benjamin Neuenswander,
• Gerald H. Lushington and
• Paul R. Hanson

Beilstein J. Org. Chem. 2012, 8, 1293–1302, doi:10.3762/bjoc.8.147

• (cyclic sulfonamides) represent a class of compounds with a non-natural chemotype [5][6] that have gained enormous interest in recent years due to their extensive range of biological activities [7][8][9][10][11][12][13][14]. In particular, benzofused sultams, possessing a rich content of sp3 amine

Hybrid super electron donors – preparation and reactivity

• Jean Garnier,
• Douglas W. Thomson,
• Shengze Zhou,
• Phillip I. Jolly,
• Leonard E. A. Berlouis and
• John A. Murphy

Beilstein J. Org. Chem. 2012, 8, 994–1002, doi:10.3762/bjoc.8.112

• ] afforded aryl anions from the same substrates by transfer of two electrons at room temperature, and also cleaved selected sulfonamides [19], bis-sulfones [19], Weinreb amides [22], acyloin derivatives [24], triflate esters and triflamides [26]. Most recently, we announced the synthesis of the unstable

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

• refluxed for 24 h. After removal of the solvent in vacuo, the residue was dried by the addition and evaporation of toluene three times, and used directly in the next step without any further purification. General procedure B, preparation of sulfonamides 8: The isatin-derived triazine 9 was suspended in THF

Equilibrium constants and protonation site for N-methylbenzenesulfonamides

• José A. Moreira,
• Ana M. Rosa da Costa,
• Luis García-Río and
• Márcia Pessêgo

Beilstein J. Org. Chem. 2011, 7, 1732–1738, doi:10.3762/bjoc.7.203

• above spectra is the absolute lack of isosbestic points, which arises from the shift in the n → π* absorption bands of the sulfonamides as the acid concentration increases. In order to eliminate this effect, the spectra must be treated by the characteristic vectors analysis (CVA) method [39]. This

• -benzisothiazoline 1,1-dioxide in fluorosulfonic acid protonated on the nitrogen atom, Chardin and co-workers [44] showed that protonation of sulfonamides occurred on the oxygen atom. Still, a possibility that should not be discarded is the existence of a tautomeric equilibrium between the N- and O-protonated

• structures, the latter having a greater relevance for the sulfonamides with electron-donor groups (Scheme 3). Conclusion The protonation equilibrium constants (pKBH+) for the para-substituted N-methylbenzenesulfonamides 3a–d in aqueous sulfuric acid were obtained from spectrophotometric measurements

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• -sulfonamides supported the reaction, but electron-withdrawing groups on nitrogen were needed to induce a fast reaction (Table 5, entries 3, 7 and 8). N-fluoropyridinium salts (Table 5, entries 4–6) gave rise to slow catalyses. With the exception of the dicationic N,N'-difluorobipyridinium salt (Table 5, entry

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• series of benzo-fused sultams. A range of α-bromobenzenesulfonyl chlorides 40 were first coupled with various amines in DMF at room temperature in the presence of Et3N to generate intermediate sulfonamides 41. Subsequent in situ addition of a Michael acceptor in large excess together with Et3N, Bu4NCl

• . Synthesis of pyrroles by cyclization of propargyl amines. Isoindolone and phthalazone synthesis by cyclization of acylhydrazides. Sultam synthesis by cyclization of sulfonamides. Synthesis of sulfonamides by aminosulfonylation of aryl iodides. Pyrrolidine synthesis by carbopalladation of allylamines

Amine-linked diglycosides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays

• Ian Cumpstey,
• Jens Frigell,
• Elias Pershagen,
• Tashfeen Akhtar,
• Elena Moreno-Clavijo,
• Inmaculada Robina,
• Dominic S. Alonzi and
• Terry D. Butters

Beilstein J. Org. Chem. 2011, 7, 1115–1123, doi:10.3762/bjoc.7.128

• investigations into this area [6] we found that the installation of amine linkages between primary–primary carbons of monosaccharides was relatively straightforward; this was achieved by Mitsunobu coupling between carbohydrate C-6 alcohols and carbohydrate C-6 sulfonamides. Primary–secondary linkages were more