Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• dye 13a displays an intense absorption at 528 nm (ε = 27,000 M−1·cm−1) corresponding to the S0→S1 (π–π* transition). The slight red shift of this absorption compared to unsubstituted BODIPY dyes in the 2,6-substitution positions and measured under similar aqueous conditions, is likely due to the

• large Stokes shift of 6850 cm−1 and a longer excited state life time (τ = 71.7 ns) [72]. Again the excitation spectrum matches the absorption one proving that aggregation is unlikely under the used aqueous conditions. From a general point of view, fluorescent probes have been used for the detection of

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• no better reason than intuitive inclination or accustomed habit, commonly direct an organic chemist to adopt the ubiquitous Schotten–Baumann-type alkaline acylation conditions (albeit not necessarily the aqueous conditions used in the original procedure) [3], both for attachment of prerequisite

• -component Mannich reactions under aqueous conditions [65][66][67]. Use of chemoselective O-acylation of hydroxyproline for preparation of polymeric organocatalysts The last couple of years have witnessed an interesting proliferation in the use of chemoselective O-acylation of hydroxyproline with acrylic

• [69], magnetic core-shell nanoparticles (with magnetite cores and polyacrylate shells) [70], and thermoresponsive block copolymers [71]. Such catalytic systems can exhibit excellent organocatalytic activity under aqueous conditions, and many of them can be recycled and reused. A rather unique property

Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test

• Gerald Jarre,
• Steffen Heyer,
• Elisabeth Memmel,
• Thomas Meinhardt and
• Anke Krueger

Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288

• , the linkers are coupled to the diamond surface via heteroatoms. These sites are more easily cleaved compared to carbon–carbon single bonds, e.g., in a physiological environment or other aqueous conditions. It is hence of interest to develop methods that form stable bonds between the diamond surface

Heronapyrrole D: A case of co-inspiration of natural product biosynthesis, total synthesis and biodiscovery

• Jens Schmidt,
• Zeinab Khalil,
• Robert J. Capon and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2014, 10, 1228–1232, doi:10.3762/bjoc.10.121

• framework, a cyclization event that was driven to completion by treatment with camphorsulfonic acid under non-aqueous conditions. Subsequent heating in H2O/MeCN containing catalytic amounts of p-TsOH led to quantitative N-deprotection, while chromatographic purification of the resulting mixture provided

On the mechanism of photocatalytic reactions with eosin Y

• Michal Majek,
• Fabiana Filace and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

• SET-generation of aryl radicals from arenediazonium salts by photocatalysis proceeds in the absence of base. The non-aqueous conditions should not provide a significant buffering capacity. Here, the presence of only minute amount of impurities in the solvents or starting materials is sufficient to

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

• stable towards aqueous conditions, and the procedures can hardly be modulated according to specific requirements. As for mechanistic investigations, the nature of the catalytically active copper(I) complex is unknown and there is scarcely any chance to rationally explain the results of kinetic studies

C–C Bond formation catalyzed by natural gelatin and collagen proteins

• Dennis Kühbeck,
• Basab Bijayi Dhar,
• Eva-Maria Schön,
• Carlos Cativiela,
• Vicente Gotor-Fernández and
• David Díaz Díaz

Beilstein J. Org. Chem. 2013, 9, 1111–1118, doi:10.3762/bjoc.9.123

• % of the product yield obtained in the presence of gelatin (entries 2 and 4), demonstrating the inherent catalytic activity of the protein under both organic and aqueous conditions. In order to completely suppress the background contribution from the reaction media and concentrate on the pure effect of

Aqueous reductive amination using a dendritic metal catalyst in a dialysis bag

• Jorgen S. Willemsen,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 960–965, doi:10.3762/bjoc.9.110

• examples, we decided to design a metallodendrimer that would show catalytic activity in a cascade process while compartmentalized under aqueous conditions. To this end, an iridium catalyst was selected that was known to be suitable for reductive amination in an aqueous environment. We showed that by

Glycosylation efficiencies on different solid supports using a hydrogenolysis-labile linker

• Mayeul Collot,
• Steffen Eller,
• Markus Weishaupt and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 97–105, doi:10.3762/bjoc.9.13

• , different solid supports have been developed (Figure 1, [27][28]). The most commonly used solid support for organic synthesis is the Merrifield resin [1]. This polystyrene (PS) resin shows good swelling properties in organic media but is not compatible with the aqueous conditions that are often required for

• further optimization of this system was not pursued. To enable rapid LC–MS analysis and to exclude solubility issues caused by aqueous conditions during hydrogenolysis, the amino-functionalized resins 18–22 were equipped with an additional Zemplén cleavage site. To this end, insert 2 was coupled to these

• protecting group of the glucosamine was reduced under Staudinger conditions (Scheme 6, Supporting Information File 1). Therefore, imidate 34 was glycosylated to functionalized resin 23. In the next step the azide was reduced by using PMe3 under basic and aqueous conditions. The use of THF swelled the PS

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• to Grignard reagents that can be employed under aqueous conditions [58]. Initially, the α-photodecarboxylation of phthaloyl glycine 44 (Scheme 16) was investigated in a microflow Dwell device and compared with the reaction under batch conditions. The microflow reactor required a shorter residence

Asymmetric one-pot sequential Friedel–Crafts-type alkylation and α-oxyamination catalyzed by a peptide and an enzyme

• Kengo Akagawa,
• Ryota Umezawa and
• Kazuaki Kudo

Beilstein J. Org. Chem. 2012, 8, 1333–1337, doi:10.3762/bjoc.8.152

• oxyamination, even though indoles are generally prone to be oxidized [39][40]. By considering that enzymes promote reactions efficiently under aqueous conditions, we thought it necessary to conduct the one-pot reaction in aqueous media. Therefore, the reaction sequence shown in Table 1 was first examined in

Combined bead polymerization and Cinchona organocatalyst immobilization by thiol–ene addition

• Kim A. Fredriksen,
• Tor E. Kristensen and
• Tore Hansen

Beilstein J. Org. Chem. 2012, 8, 1126–1133, doi:10.3762/bjoc.8.125

• enhanced activity and selectivity sometimes exhibited by such organocatalysts, especially under aqueous conditions [2]. Recently, the use of polymer-supported organocatalysts in continuous-flow systems has also surfaced in the literature, and their development is quickly gaining momentum [3][4][5

A general and facile one-pot process of isothiocyanates from amines under aqueous conditions

• Nan Sun,
• Bin Li,
• Jianping Shao,
• Weimin Mo,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2012, 8, 61–70, doi:10.3762/bjoc.8.6

• Academy of Sciences, Lanzhou 730000, China 10.3762/bjoc.8.6 Abstract A general and facile one-pot protocol for the preparation of a broad range of alkyl and aryl isothiocyanates has been developed from their corresponding primary amines under aqueous conditions. This synthetic process involves an in situ

• particularly for highly electron-deficient substrates. This novel and economical method is suitable for scale-up activities. Keywords: aqueous conditions; cyanuric acid; isothiocyanates; one-pot process; organic synthesis; primary amines; Introduction Isothiocyanates are a class of heteroallenic compounds

• dithiocarbamate by reaction of aniline and CS2 in the presence of inorganic base under aqueous conditions has already been reported, the conversion of aniline and the selection of N-phenyl dithiocarbamate have not been disclosed before. Thus, with the help of HPLC analysis, the selectivity of N-phenyl

Reductive amination with zinc powder in aqueous media

• Giovanni B. Giovenzana,
• Daniela Imperio,
• Andrea Penoni and
• Giovanni Palmisano

Beilstein J. Org. Chem. 2011, 7, 1095–1099, doi:10.3762/bjoc.7.125

• amination are compatible with aqueous conditions. A literature search revealed that imine formation is possible in water [23] and other green solvents [24]. The reduction of imine in aqueous conditions is reported for selected reagents. We were interested in the use of zinc metal in view of several factors

• different transformations under basic aqueous conditions, which may lead to extensive formation of byproducts. Results and Discussion We investigated the reaction between benzaldehyde and benzylamine (Scheme 1, R = Ph R' = Bn) in 5% aqueous NaOH solution in the presence of zinc dust under vigorous stirring

A novel high-yield synthesis of aminoacyl p-nitroanilines and aminoacyl 7-amino-4-methylcoumarins: Important synthons for the synthesis of chromogenic/fluorogenic protease substrates

• Xinghua Wu,
• Yu Chen,
• Herve Aloysius and
• Longqin Hu

Beilstein J. Org. Chem. 2011, 7, 1030–1035, doi:10.3762/bjoc.7.117

• , we prepared an aqueous solution of NaHSe and treated it with Cbz-Gly-OSu in 50% aqueous THF to produce Cbz-Gly-SeNa. The subsequent amidation with p-nitrophenyl azide afforded the desired Cbz-Gly-pNA (1) in 95% yield (Table 1, entry 1), indicating that the reaction could be carried out under aqueous

• conditions. When Fmoc-Ile-OSu reacted with NaHSe, a higher reaction temperature (room temperature) was required to complete the selenocarboxylation, suggesting the presence of steric hindrance. However, once the Fmoc-Ile-SeNa was formed, it quickly reacted with p-nitrophenyl azide to provide Fmoc-Ile-pNA (4

Kinetic studies and predictions on the hydrolysis and aminolysis of esters of 2-S-phosphorylacetates

• Milena Trmčić and
• David R. W. Hodgson

Beilstein J. Org. Chem. 2010, 6, 732–741, doi:10.3762/bjoc.6.87

• use of bromoacetate-based cross-linking agents with thiophosphate nucleophiles 3, where our aim was to generate nucleoside-pyrophosphate mimics as potential glycosyl transferase inhibitors under aqueous conditions. Initially, we focus on the use of the bromoacetic acid esters of N-hydroxybenzotriazole

Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

• Norbert Moszner,
• Iris Lamparth,
• Jörg Angermann,
• Urs Karl Fischer,
• Frank Zeuner,
• Thorsten Bock,
• Robert Liska and
• Volker Rheinberger

Beilstein J. Org. Chem. 2010, 6, No. 26, doi:10.3762/bjoc.6.26

• -butyl]acrylate [3] or 1,3-bis(methacrylamido)propane-2-yl dihydrogen phosphate (BMAMHP) [4], which show improved hydrolytic stability under acidic aqueous conditions. The visible-light (VL) photoinitiators (PIs) in current SEAs are based on mixtures of camphorquinone (CQ) and tertiary amines (A) [5

Synthesis of (S)-1-(2-chloroacetyl)pyrrolidine- 2-carbonitrile: A key intermediate for dipeptidyl peptidase IV inhibitors

• Santosh K. Singh,
• Narendra Manne and
• Manojit Pal

Beilstein J. Org. Chem. 2008, 4, No. 20, doi:10.3762/bjoc.4.20

• purified by crystallization followed by column chromatography to afford the desired amide 9 in 52% yield without exposure to aqueous conditions. To prepare the target cyano pyrrolidine 6, which was also found to be soluble in water, a solution of amide 9 in THF was treated with trifluoroacetic anhydride