Chemoenzymatic synthesis and biological evaluation of enantiomerically enriched 1-(β-hydroxypropyl)imidazolium- and triazolium-based ionic liquids

• Paweł Borowiecki,
• Małgorzata Milner-Krawczyk and
• Jan Plenkiewicz

Beilstein J. Org. Chem. 2013, 9, 516–525, doi:10.3762/bjoc.9.56

• , solvent for the ions, and medium. Most of the described optically active ILs are prepared from easily accessible natural chiral substrates [40]. The use of ILs in so-called “green chemistry”, as for example solvents in inorganic or organic syntheses or as a replacement for many hazardous and volatile

Mechanochemistry assisted asymmetric organocatalysis: A sustainable approach

• Pankaj Chauhan and
• Swapandeep Singh Chimni

Beilstein J. Org. Chem. 2012, 8, 2132–2141, doi:10.3762/bjoc.8.240

• : ball-milling; enantioselective synthesis; mechanochemistry; organocatalysis; solvent-free; Introduction Green chemistry involves innovation in chemical research and engineering that encourages the design of processes to minimize the use and production of hazardous materials and also reduce the use of

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• , apparent improvements of the solubilization obtained with the aid of organic solvents were mostly due to the formation of nanoparticulate dispersions. Since these organic solvents are also hazardous for most cells, applications in biomedicine are prohibited. Therefore, organic solvents were avoided for the

A simple and efficient dual optical signaling chemodosimeter for toxic Hg(II)

• Sabir H. Mashraqui,
• Sapna A. Tripathi,
• Sushil S. Ghorpade and
• Smita R. Britto

Beilstein J. Org. Chem. 2012, 8, 1352–1357, doi:10.3762/bjoc.8.155

• action of hazardous mercury ions in samples containing several background metal ions. In addition to the matrix experiment described above, we studied the effects of individual interferents on the fluorescence response of mercury ions. Therefore, the fluorescence spectra of the probe in the presence of

Regioselective chlorination and bromination of unprotected anilines under mild conditions using copper halides in ionic liquids

• Han Wang,
• Kun Wen,
• Nurbiya Nurahmat,
• Yan Shao,
• He Zhang,
• Chao Wei,
• Ya Li,
• Yongjia Shen and
• Zhihua Sun

Beilstein J. Org. Chem. 2012, 8, 744–748, doi:10.3762/bjoc.8.84

• Science, Shanghai, 201620, China 10.3762/bjoc.8.84 Abstract By using ionic liquids as solvents, the chlorination or bromination of unprotected anilines at the para-position can be achieved in high yields with copper halides under mild conditions, without the need for potentially hazardous operations such

Catalyst-free and solvent-free Michael addition of 1,3-dicarbonyl compounds to nitroalkenes by a grinding method

• Zong-Bo Xie,
• Na Wang,
• Ming-Yu Wu,
• Ting He,
• Zhang-Gao Le and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2012, 8, 534–538, doi:10.3762/bjoc.8.61

• environmentally hazardous residues and undesirable byproducts [25][26][27][28][29][30]. As one part of our continuing efforts toward the development of green synthesis methods for Michael additions of nitroalkenes, we have previously reported an enzymatic tandem reaction to form 5-hydroxyimino-4,5-dihydrofurans

Dioxane dibromide mediated bromination of substituted coumarins under solvent-free conditions

• Subrata Kumar Chaudhuri,
• Sanchita Roy and
• Sanjay Bhar

Beilstein J. Org. Chem. 2012, 8, 323–329, doi:10.3762/bjoc.8.35

• (stable for at least three to four months in a refrigerator); (b) a stoichiometric amount of reagent can be used by direct weighing, avoiding excess; (c) no evolution of hazardous bromine vapor during the reaction; (d) the total elimination of the use of toxic organic solvents; (e) a simple experimental

Continuous-flow hydration–condensation reaction: Synthesis of α,β-unsaturated ketones from alkynes and aldehydes by using a heterogeneous solid acid catalyst

• Magnus Rueping,
• Teerawut Bootwicha,
• Hannah Baars and
• Erli Sugiono

Beilstein J. Org. Chem. 2011, 7, 1680–1687, doi:10.3762/bjoc.7.198

• hazardous chemicals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Furthermore, continuous-flow technologies allow chemical processes to be easily and rapidly scaled up, either by changing the volume of the single reactor, by performing the reaction for an extended reaction

Continuous proline catalysis via leaching of solid proline

• Suzanne M. Opalka,
• Ashley R. Longstreet and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2011, 7, 1671–1679, doi:10.3762/bjoc.7.197

• and can be precisely controlled. In addition, continuous technology enables the generation and immediate use of unstable or hazardous intermediates [4][5][6][7][8][9] as well as the combination of many reactions in series to achieve multistep synthesis [9][10][11][12][13]. Despite the many favorable

Multistep flow synthesis of vinyl azides and their use in the copper-catalyzed Huisgen-type cycloaddition under inductive-heating conditions

• Lukas Kupracz,
• Jan Hartwig,
• Jens Wegner,
• Sascha Ceylan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2011, 7, 1441–1448, doi:10.3762/bjoc.7.168

• process for the generation of vinyl azides 4 is the two-step protocol developed by Hassner et al. [9] through the in situ reaction of sodium azide with iodine chloride in dichloromethane or another polar solvent (Scheme 1). Thus, it includes the generation of hazardous and highly explosive iodine azide

• requires further optimization. This and other examples [11][12][13] principally demonstrate that flow chemistry is an ideal enabling technology [14] for generating and utilizing hazardous azido reagents because only small amounts are generated at a time and are subsequently consumed in situ. The other

• the use of explosive and hazardous iodine azide. Experimental General procedure for azido iodination of alkenes 2 under flow conditions A glass reactor (12 cm length and 8.5 mm internal diameter) was filled with polymer-bound iodate(I) complex 5 (5 g; theoretical loading = 3.5 mmol/g) and protected

Unusual behavior in the reactivity of 5-substituted-1H-tetrazoles in a resistively heated microreactor

• Bernhard Gutmann,
• Toma N. Glasnov,
• Tahseen Razzaq,
• Walter Goessler,
• Dominique M. Roberge and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2011, 7, 503–517, doi:10.3762/bjoc.7.59

• toxic but also highly explosive, a scale-up of this batch protocol is clearly not possible. A key advantage of using microreactors compared to conventional batch reactors is the ability to process potentially hazardous compounds or reagents safely [1][2][3][4][5][6][7][8][9][29][30][31][32]. In a

A two step synthesis of a key unit B precursor of cryptophycins by asymmetric hydrogenation

• Benedikt Sammet,
• Mathilde Brax and
• Norbert Sewald

Beilstein J. Org. Chem. 2011, 7, 243–245, doi:10.3762/bjoc.7.32

• enantioselectivity, and avoids hazardous reaction conditions. Keywords: amino acid; asymmetric hydrogenation; cryptophycin; DuPhos; Introduction Cryptophycins are macrocyclic depsipeptides, which show very high cytotoxicity even against multidrug-resistant cell lines. They inhibit mitosis of eukaryotic cells by

• cryptophycin unit B precursor 4 is disclosed based on a HWE reaction followed by a highly enantioselective [(COD)Rh-(R,R)-Et-DuPhos]BF4 mediated asymmetric hydrogenation. This high-yielding access is more convenient and avoids hazardous chemicals in contrast to the established method. The four building blocks

Systematic investigations on the reduction of 4-aryl-4-oxoesters to 1-aryl-1,4-butanediols with methanolic sodium borohydride

• Subrata Kumar Chaudhuri,
• Manabendra Saha,
• Amit Saha and
• Sanjay Bhar

Beilstein J. Org. Chem. 2010, 6, 748–755, doi:10.3762/bjoc.6.94

• oxidation state of the alkoxycarbonyl moiety (Scheme 3). From the results obtained so far, it is obvious that NaBH4 in methanol can be efficiently used for the synthesis of 1-aryl-1,4-butanediols from the easily accessible 4-aryl-4-oxoesters (Table 1) instead of employing the more costly and hazardous

C-Arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions

• Mazaahir Kidwai,
• Saurav Bhardwaj and
• Roona Poddar

Beilstein J. Org. Chem. 2010, 6, No. 35, doi:10.3762/bjoc.6.35

• overcome from these problems, we have investigated a new catalytic system for C-arylation. Nanocrystalline metal oxides find numerous applications, e.g., as active adsorbents for gases [20], the destruction of hazardous materials [21] and the oxidation of volatile organic compounds [22]. In addition, metal

Efficient and improved synthesis of Telmisartan

• A. Sanjeev Kumar,
• Samir Ghosh and
• G. N. Mehta

Beilstein J. Org. Chem. 2010, 6, No. 25, doi:10.3762/bjoc.6.25

• published procedures start from this compound. In designing an alternative synthesis of Telmisartan our goal was to minimize the use of expensive and hazardous metals, circumvent the bromination step, and increase the overall efficiency of the synthesis. This was accomplished by reversing the order of the

Controlling hazardous chemicals in microreactors: Synthesis with iodine azide

• Johan C. Brandt and
• Thomas Wirth

Beilstein J. Org. Chem. 2009, 5, No. 30, doi:10.3762/bjoc.5.30

• reaction conditions in microreactors. Keywords: azide; flow chemistry; hazardous reagents; microreactor; rearrangement; Introduction Microstructured devices have already found their way into organic synthesis, because they offer various advantages over traditional large-scale chemistry performed in

• potentially hazardous compounds is another advantage of microreactors as only very small amounts of compounds/reagents are handled. Large inventories of dangerous reagents and intermediates are not necessary. Azides are among the most versatile reagents in modern organic chemistry however they are not often

• other functional groups [5]. Iodine azide is a very hazardous but valuable reagent that is easier and much more safely handled under microreactor conditions. Iodine azide is a solid compound, highly explosive and toxic. It is known to add stereospecifically to carbon–carbon double bonds with high

From discovery to production: Scale- out of continuous flow meso reactors

• Peter Styring and
• Ana I. R. Parracho

Beilstein J. Org. Chem. 2009, 5, No. 29, doi:10.3762/bjoc.5.29

• dealing with large scale syntheses and at times it may be economically sensible to move a reactor to the supply source rather than vice versa, particularly where hazardous chemical feedstocks are involved [5]. Furthermore, small footprint processes would be advantageous for safety reasons, particularly

The development and evaluation of a continuous flow process for the lipase- mediated oxidation of alkenes

• Charlotte Wiles,
• Marcus J. Hammond and
• Paul Watts

Beilstein J. Org. Chem. 2009, 5, No. 27, doi:10.3762/bjoc.5.27

• ] or peracids [6] such as m-chloroperbenzoic acid (m-CPBA) [7][8]. The hazardous nature of these techniques and the potential to hydrolyse the epoxide [9] however precludes their use on a large scale. Many of the epoxides produced industrially are synthesised using the chlorohydrin method, or via in

• two cycles (60%) affording complete deactivation of the enzyme on the third cycle; yields in the range of 73 to 85% were however obtained upon adding the oxidant in aliquots over a period of 24 h. Although the chemo-enzymatic epoxidation of alkenes is an attractive alternative to the hazardous

Oxidative cyclization of alkenols with Oxone using a miniflow reactor

• Yoichi M. A. Yamada,
• Kaoru Torii and
• Yasuhiro Uozumi

Beilstein J. Org. Chem. 2009, 5, No. 18, doi:10.3762/bjoc.5.18

• inexpensive oxidant for this transformation [35][36][37][38][39][40][41][42], Oxone however is also a known fire and explosion hazard [43] essentially rendering its large-scale use impractical. To avoid these potentially dangerous and hazardous conditions in a large-scale batch oxidation, we switched the

An improved synthesis of 1,3,5-triaryl- 2-pyrazolines in acetic acid aqueous solution under ultrasound irradiation

• Ji-Tai Li,
• Xiao-Hui Zhang and
• Zhi-Ping Lin

Beilstein J. Org. Chem. 2007, 3, No. 13, doi:10.1186/1860-5397-3-13

• organic synthesis in that new reaction conditions need to be found which reduce the emission of volatile organic solvents and the use of hazardous toxic chemicals. Organic reactions in aqueous media have attracted increasing interest currently because of environmental issues and the understanding of

EcoScale, a semi- quantitative tool to select an organic preparation based on economical and ecological parameters

• Koen Van Aken,
• Lucjan Strekowski and
• Luc Patiny

Beilstein J. Org. Chem. 2006, 2, No. 3, doi:10.1186/1860-5397-2-3

• not take into account the nature and environmental impact of the generated waste. In order to arrive at a more meaningful prediction, the E-factor is multiplied by a environmentally hazardous quotient Q. For example, a Q value of 1 can be attributed to NaCl, while heavy metals can be assigned a value

• new products are fully characterized. Finally, one should never forget that the combination of certain individual compounds can create a hazardous situation (e.g. exothermic reaction between acids and bases). For assessing these hazards, a wide variety of information is readily available, such as the