Formation of epoxide-amine oligo-adducts as OH-functionalized initiators for the ring-opening polymerization of ε-caprolactone

• Julia Theis and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 938–944, doi:10.3762/bjoc.6.105

• ) irradiation in organic, pharmaceutical and polymer chemistry has become a well-established technique to promote chemical reactions. In many cases, the main advantages of this physical heating method over traditional heating in an oil bath are increases in reaction speed, product yields and purity [1][2][3][4

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

• has been found to be suitable because of its higher solubility in water compared to β-cyclodextrin (800.5 g L−1 vs. 18.5 g L−1) [27][28][29]. Chemical reactions between two incompatible reactants can also be achieved under heterogeneous reaction conditions (the reaction is localized at the interphase

Synthesis in the glycosciences

• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2010, 6, No. 16, doi:10.3762/bjoc.6.16

• presented in this series. Furthermore, carbohydrate chemistry is presented in the context of chemical biology together with organic chemistry making use of known chemical reactions as well as the stereochemical advantages of saccharides to construct novel molecules with unique properties. It has been a joy

Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis

• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2009, 5, No. 70, doi:10.3762/bjoc.5.70

• ]. In many cases shorter reaction times have been reported compared to the traditional heating methods. The question of a specific microwave effect is under current discussion, but for many chemical reactions it is evident that microwave heating is just another way transferring heat into the reaction

• operated mini reactor for chemical reactions using readily available laboratory equipment. In this sense it is an enabling technology allowing the use of continuous reactors at low cost, enlarging the portfolio of enabling technologies for organic synthesis [27]. Performing a simple organic reaction

• determined. The system gives the opportunity to adjust accurately high heating rates with traditional resistive electric heating. This feature makes the device a tool well suited to compare the influence of heating rates on chemical reactions. Further studies will focus on the comparison of heating within

Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

• Monika Gupta,
• Rajive Gupta and
• Medha Anand

Beilstein J. Org. Chem. 2009, 5, No. 68, doi:10.3762/bjoc.5.68

• . Thus, the use of aqueous solvents in chemical reactions has proved a cleaner and safer alternative to organic solvents [2]. Heterogeneous catalysis, which has the immediate advantage of easy recoverability and recyclability of the catalyst – sometimes with the further advantage of increased selectivity

Can we measure catalyst efficiency in asymmetric chemical reactions? A theoretical approach

• Shaimaa El-Fayyoumy,
• Matthew H. Todd and
• Christopher J. Richards

Beilstein J. Org. Chem. 2009, 5, No. 67, doi:10.3762/bjoc.5.67

• such a comparison. We propose that a catalyst is more efficient if fewer atoms are utilised to give a product in a required enantiomeric excess. We illustrate this concept by analysing several well-known asymmetric catalytic chemical reactions carried out in academic laboratories, and compare small

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• ; Introduction Flavins are redox-active chromophores [1][2][3][4][5][6] and represent one of the most abundant classes of natural enzyme co-factors [7][8][9]. Recently, the photo redox properties of flavins have been used to catalyze chemical reactions [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24

Continuous flow based catch and release protocol for the synthesis of α-ketoesters

• Alessandro Palmieri,
• Steven V. Ley,
• Anastasios Polyzos,
• Mark Ladlow and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2009, 5, No. 23, doi:10.3762/bjoc.5.23

• and release; flow synthesis; α-ketoesters; mesoreactor; polymer supported reagents; Introduction Organic synthesis is changing rapidly owing to the discovery of processes that challenge current dogma and lead to the invention of new chemical reactions [1][2]. Likewise, new synthesis tools are

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• alternatives to the traditional ‘round-bottomed flask’ concept, which is still typically widely used for most chemical reactions [1][2][3][4][5][6][7][8]. Many advantages have been attributed to the use of flow devices, such as improved heat and mass transfer as well as mixing, and also easier scale-up and

Synthesis of unsymmetrically substituted biaryls via sequential lithiation of dibromobiaryls using integrated microflow systems

• Aiichiro Nagaki,
• Naofumi Takabayashi,
• Yutaka Tomida and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2009, 5, No. 16, doi:10.3762/bjoc.5.16

• conducting reactions without decomposing such intermediates [34][35][36][37][38][39][40]. Moreover, microflow systems serve as effective ways of integrating chemical reactions, in which an initial product is used for a subsequent transformation [41][42][43][44][45][46][47][48][49][50][51]. For example

Photosonochemical catalytic ring opening of α-epoxyketones

• Hamid R. Memarian and
• Ali Saffar-Teluri

Beilstein J. Org. Chem. 2007, 3, No. 2, doi:10.1186/1860-5397-3-2

• chemical reactions include higher yields, shorter reaction times and milder reaction conditions when compared with classical methods. [1][2][3][4][5] The effect of ultrasound has mostly been shown by increasing the yields of reactions and in some cases changing the ratio of products formed. The most

Study of thioglycosylation in ionic liquids

• Jianguo Zhang and
• Arthur Ragauskas

Beilstein J. Org. Chem. 2006, 2, No. 12, doi:10.1186/1860-5397-2-12

• polarity can be routinely accomplished by altering the nature of the ion pair or altering the nature of the alkyl group on the substituted organic cation.[2] These structural variations substantially broaden the scope and versatility of ILs applications. Many chemical reactions have been carried out in

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

• between 100–1000 on the basis of their toxicity. Based on the environmental quotient, a computer program has been developed (EATOS of Environmental Assessment Tool for Organic Synthesis) [11] that can be used to compare and improve chemical reactions. Effective mass yield [12] This parameter is defined as