New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones

• Emilian Georgescu,
• Alina Nicolescu,
• Florentina Georgescu,
• Florina Teodorescu,
• Daniela Marinescu,
• Ana-Maria Macsim and
• Calin Deleanu

Beilstein J. Org. Chem. 2014, 10, 2377–2387, doi:10.3762/bjoc.10.248

• structures have been proposed [7][8]. The correct structure of 2,3-dicarbomethoxy-5-methylpyrrolo[1,2-a]quinoxalin-4-one and the reaction mechanism was proposed by Meth-Cohn [9]. The reactions of 1-substituted 3-(ethoxycarbonylmethyl)benzimidazolium bromides with fluoroalkenes [10] or fluorovinyl tosylates

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

• Jan Szabo,
• Kerstin Karger,
• Nicolas Bucher and
• Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

• halides, tosylates and triflates. In our hands, solvent-free heterogenous mixtures of the solid guanidinium salt and a liquid alkylating reagent did not react as desired. Therefore, we developed a two-step alkylation procedure, by which the catalytic hydrogenation of 1,2,3-tris(benzyliminyl)guanidinium

Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

• Mahesh K. Lakshman,
• Manish K. Singh,
• Mukesh Kumar,
• Raghu Ram Chamala,
• Vijayender R. Yedulla,
• Domenick Wagner,
• Evan Leung,
• Lijia Yang,
• Asha Matin and
• Sadia Ahmad

Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200

• decided to investigate other reactive BtOH derivatives for this reaction. A variety of phosphorus and sulfonate derivatives of BtOH has been synthesized and studied as peptide-coupling agents [30]. Amongst these we selected the easily synthesized tosylates of BtOH (Bt-OTs) and its 7-aza analogue AtOH (At

• alkyl halides or more cumbersome methods. Mechanistic studies indicate that reactions of alcohols with these peptide-coupling reagents, in the presence of a base, appear to proceed by formation of alcohol phosphonium derivatives (with BOP), or alcohol tosylates (with Bt-OTs), and not through direct

A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges

• Martin Popr,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2014, 10, 1390–1396, doi:10.3762/bjoc.10.142

• in a MeOH/H2O (1:1 v/v) mixture, which affords pure 1 after the third run in the satisfying overall yield of 26%. TLC and detection by carbonization proved to be a very simple yet very sensitive method to follow the purity of the tosylates. For the monotosylation of α- and γ-CDs the reaction in water

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• easily be derived from the corresponding ketone and they are more reactive then the vinyl chloride or bromide during the oxidative addition. More recently also vinyl tosylates and enol phosphates have proven to be suitable reagents. The catalytic arylic C–P cross-coupling reaction can be a greener

• ][163]. Julienne et al. succeeded in coupling vinyl tosylates 85 and 87 with diphenylphosphine borane 13e despite the fact that alkenyl tosylates are poor reagents for cross-coupling [164]. The products 86 and 79b were formed in the presence of a palladium catalyst. The reaction proceeded at lower

Polyglycerol-functionalized nanodiamond as a platform for gene delivery: Derivatization, characterization, and hybridization with DNA

• Li Zhao,
• Yuki Nakae,
• Hongmei Qin,
• Tadamasa Ito,
• Takahide Kimura,
• Hideto Kojima,
• Lawrence Chan and
• Naoki Komatsu

Beilstein J. Org. Chem. 2014, 10, 707–713, doi:10.3762/bjoc.10.64

• engineering. The synthetic route from ND50-PG to ND-PG-BPP is shown in Scheme 1. Some of the hydroxy groups of ND50-PG were reacted with tosyl chloride (TsCl) in pyridine and the resulting tosylates (ND-PG-OTs) were substituted by azide (ND-PG-N3). The azido groups reacted with the alkyne group at the end of

Consecutive cross-coupling reactions of 2,2-difluoro-1-iodoethenyl tosylate with boronic acids: efficient synthesis of 1,1-diaryl-2,2-difluoroethenes

• Ju Hee Kim,
• Su Jeong Choi and
• In Howa Jeong

Beilstein J. Org. Chem. 2013, 9, 2470–2475, doi:10.3762/bjoc.9.286

• -arylethenyl tosylates 3 in excellent isolated yields. Especially, the coupling reactions with arylboronic acids having an electron-donating group at the ortho-position of the benzene ring also provided the corresponding coupled products 3l–n in good yields. The cross-coupling reactions of 2 with arylboronic

• acids are summarized in Table 2. Direct diarylation reactions of 2 with arylboronic acids were also performed because di-coupled product 4a was formed in a mono-arylation reaction (Table 1) and also a recent work showed a successful cross-coupling reaction of nonfluorinated enol tosylates with a variety

• step. The di-coupling reactions of 2 with arylboronic acids are summarized in Table 4. Unsymmetrical 1,1-diaryl-2,2-difluoroethenes can be prepared from the coupling reaction of mono-coupled tosylates 3 with arylboronic acids under similar reaction conditions. Therefore, the cross-coupling reaction of

Cyclization of substitued 2-(2-fluorophenylazo)azines to azino[1,2-c]benzo[d][1,2,4]triazinium derivatives

• Aleksandra Jankowiak,
• Emilia Obijalska and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2013, 9, 1873–1880, doi:10.3762/bjoc.9.219

• lamp in the presence of Ca(OTs)2 [7], and cations 1b and 1e were isolated as tosylates in 75% and 95% yield, respectively. Under these conditions diazenes 4c and 4d underwent cyclization, but the resulting cations 1c and 1d were unstable and partially decomposed during the reaction. Therefore, their

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• that normally observed for unfunctionalized epoxides [44]. This is proposed to be an effect of the coordinating ability of Lewis basic oxygen atoms in tosylates and esters, which may disrupt the binding and directing effect of phenyl or alkenyl groups. In the case of the ripostatin A model system, the

Easy and direct conversion of tosylates and mesylates into nitroalkanes

• Alessandro Palmieri,
• Serena Gabrielli and
• Roberto Ballini

Beilstein J. Org. Chem. 2013, 9, 533–536, doi:10.3762/bjoc.9.58

• Alessandro Palmieri Serena Gabrielli Roberto Ballini “Green Chemistry Group”, School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy 10.3762/bjoc.9.58 Abstract Tosylates and mesylates were directly converted into the

• corresponding nitroalkanes, by their treatment with tetrabutylammonium nitrite (TBAN) under mild conditions. Keywords: mesylates; nitroalkanes; nucleophilic substitution; tetrabutylammonium nitrite; tosylates; Introduction Nitroalkanes have proven to be one of the most valuable, versatile classes of

• source for nitroalkanes, have unsuccessful been explored in the past [28]. In fact, the conversion of alcohols into nitroalkanes requires a three-step sequence, as reported in Figure 1, that necessitates [29][30][31][32][33] (i) conversion of alcohols a into their tosylates or mesylates b, (ii

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• compared with the reported carbomagnesiation reactions [124][125][126][127][128][129]. Hoveyda reported zirconium-catalyzed alkylmagnesiation reactions of styrene in 2001 by using primary or secondary alkyl tosylates as alkyl sources [130]. The reactions proceeded through zirconacyclopropane 4F as a key

Synthesis and in silico screening of a library of β-carboline-containing compounds

• Kay M. Brummond,
• John R. Goodell,
• Matthew G. LaPorte,
• Lirong Wang and
• Xiang-Qun Xie

Beilstein J. Org. Chem. 2012, 8, 1048–1058, doi:10.3762/bjoc.8.117

• tosylates was not successful. Next, compounds possessing the cyclobutene-fused β-carboline skeleton were assembled from the versatile allenyl intermediate 6. For this subset of compounds, acylation of the sterically hindered amine of 6{1} with the ynoic acids 8{1–8}, by using bromo-tris-pyrrolidino

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• , tosylates, mesylates and phosphonates. Research efforts in this field are now focused on mechanism considerations since the broad diversity of catalytic metalation pathways represents undoubtedly an attractive tool for regioselectivity and the development of novel methodologies. Up until very recently

• calculations on oxazole-4-carboxylate; (b) Developed novel CMD direct arylation methodologies. aTS CMD Free Gibbs energy; bHOMO coefficient; cpartial charge (ESP). Pd(0)-catalyzed direct arylation of (benz)oxazoles with tosylates and mesylates [71]. Pd(0)-catalyzed direct arylation of oxazoles with sulfamates

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• allenoates 364 and various terminal alkynes [172]. The González group developed an intermolecular reaction of internal alkynes and imines, in which the propargyl tosylates 367 react with N-tosylaldimines 368 to afford cyclopent-2-enimines 369 [173]. The final product was achieved through a 1,2-migration of

The preparation of 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

• Bryan Ringstrand,
• Martin Oltmanns,
• Jeffrey A. Batt,
• Aleksandra Jankowiak,
• Richard P. Denicola and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2011, 7, 386–393, doi:10.3762/bjoc.7.49

• ; Introduction 3-Substituted 1,5-dibromopentanes I and disulfonates, typically tosylates II, serve as useful intermediates in the preparation of six-membered heterocycles such as 4-substituted-piperidines III, thianes IV, silacyclohexanes V, and phosphorinanes VI (Figure 1). The piperidines III (Y = Ar) have

Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s

• Richard Hoogenboom,
• Martin W. M. Fijten,
• Guido Kickelbick and
• Ulrich S. Schubert

Beilstein J. Org. Chem. 2010, 6, 773–783, doi:10.3762/bjoc.6.96

• of well-defined polymer architectures is of major importance for the development of complex functional materials. In this contribution, we discuss the synthesis of a range of multifunctional star-shaped tosylates as potential initiators for the living cationic ring-opening polymerization (CROP) of 2

• -oxazolines resulting in star-shaped polymers. The synthesis of the tosylates was performed by esterification of the corresponding alcohols with tosyl chloride. Recrystallization of these tosylate compounds afforded single crystals, and the X-ray crystal structures of di-, tetra- and hexa-tosylates are

• reported. The use of tetra- and hexa-tosylates, based on (di)pentaerythritol as initiators for the CROP of 2-ethyl-2-oxazoline, resulted in very slow initiation and ill-defined polymers, which is most likely caused by steric hindrance in these initiators. As a consequence, a porphyrin-cored tetra-tosylate

Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

• Bruno Linclau,
• Leo Leung,
• Jean Nonnenmacher and
• Graham Tizzard

Beilstein J. Org. Chem. 2010, 6, No. 62, doi:10.3762/bjoc.6.62

• , mesylate 11, and bromide 12 as precursors for chain extension. Nucleophilic substitution of similar tosylates with phenolate nucleophiles has been previously described [18]. Reaction of 9–12 with a number of carbon nucleophiles was investigated. Unfortunately, reaction of 9–12 with alkyl Grignard and

Dimerization of propargyl and homopropargyl 6-azido- 6-deoxy- glycosides upon 1,3-dipolar cycloaddition

• Nikolas Pietrzik,
• Daniel Schmollinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2008, 4, No. 30, doi:10.3762/bjoc.4.30

• -azido-6-deoxy-glycosides 4 were prepared via the corresponding tosylates 3 as described above. Scheme 2 summarizes the yields for the preparation of the tosylates 3 and 6-azido-6-deoxy-glycosides 4. Starting materials 1 were prepared following known procedures for 1a [13][20], 1b [21], 1d [13], 1f [20

Synthesis of phosphorothioates using thiophosphate salts

• Babak Kaboudin and
• Fatemeh Farjadian

Beilstein J. Org. Chem. 2006, 2, No. 4, doi:10.1186/1860-5397-2-4

• benzoyl chloride Reaction of triethylammonium O,O'-diethyl thiophosphate with benzoyl chloride Synthesis of phosphorothioates using triethylammonium O,O'-diethyl thiophosphate using microwave irradiation. Reaction of alkyl halides and tosylates in the presence of a mixture of triethyl amine/sulfure