Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

• Teresa Weise,
• Marco Kai,
• Anja Gummesson,
• Armin Troeger,
• Stephan von Reuß,
• Silvia Piepenborn,
• Francine Kosterka,
• Martin Sklorz,
• Ralf Zimmermann,
• Wittko Francke and
• Birgit Piechulla

Beilstein J. Org. Chem. 2012, 8, 579–596, doi:10.3762/bjoc.8.65

• range between 30 and 250 with signals that were significantly enhanced (5% confidence level) compared to those of the blank control samples. If the proton affinity of an analyte molecule is higher than the one of H3O+ the proton transfer reaction is more or less quantitative (quasi-first-order reaction

• kinetics). Thus the detection efficiency of compounds is rather independent of the nature of the analyzed molecule [53] and the signal obtained by normalization of the measured count rate to the primary ion count rate is roughly proportional to the concentration. The headspace concentrations measured by

Synthesis of heteroglycoclusters by using orthogonal chemoselective ligations

• Baptiste Thomas,
• Michele Fiore,
• Isabelle Bossu,
• Pascal Dumy and
• Olivier Renaudet

Beilstein J. Org. Chem. 2012, 8, 421–427, doi:10.3762/bjoc.8.47

• ) catalyst (delivered either using CuI, copper micropowder, or CuSO4 and sodium ascorbate as reducing agent) and the utilization of microwave or ultrasonic irradiation are parameters that can influence the reaction kinetics, improve the yields and sometimes prevent side reactions. In a previous study, we

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• homogeneous scFs media can be altered by changing these parameters [26][27]. Selected examples of phase equilibrium-controlled chemical reaction kinetics in high pressure CO2 have been reviewed elsewhere [28]. Nevertheless, examples exploiting the great potential of the combined use of immobilized catalysts

The Eschenmoser coupling reaction under continuous-flow conditions

• Sukhdeep Singh,
• J. Michael Köhler,
• Andreas Schober and
• G. Alexander Groß

Beilstein J. Org. Chem. 2011, 7, 1164–1172, doi:10.3762/bjoc.7.135

• desired Eschenmoser coupling products were obtained within 70 s residence time. The reaction kinetics was investigated and 15 examples of different building block combinations are given. Keywords: activation energy; episulfide; flow chemistry; keto imine; kinetics; S-alkylation; sulfide contraction

• comparable good yields and high reaction selectivities. In the case of higher flow rate, of 1000 µL/min and beyond, and the corresponding shorter reaction time, a decreased conversion was observed due to the slow reaction kinetics (Figure 1). The flow chemistry technique allows the determination of reaction

• /mol, and a frequency factor A of about 3.73 × 109 s−1, were found. This activation energy is obviously the reason for the slow reaction kinetics at moderate temperature. Hence, the application of pressurized high temperature conditions should lead to significant reaction intensification. For the

Asymmetric Au-catalyzed cycloisomerization of 1,6-enynes: An entry to bicyclo[4.1.0]heptene

• Alexandre Pradal,
• Chung-Meng Chao,
• Patrick Y. Toullec and
• Véronique Michelet

Beilstein J. Org. Chem. 2011, 7, 1021–1029, doi:10.3762/bjoc.7.116

• evaluated in various solvents and proceeded smoothly leading to the desired alkene 3a [59]. The reaction kinetics and stereoselectivity were found to be highly solvent-dependent, the enantiomeric excesses (ee) varying from 31% to 78% at room temperature (Table 1, entries 1–3). The reaction kinetic was very

Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold–triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization

• Hideto Ito,
• Tomoya Harada,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2011, 7, 951–959, doi:10.3762/bjoc.7.106

• , it is concluded that the acceleration effect by L1 is not due to an electronic effect rather a steric effect. The time–conversion profiles shown in Figure 3 clearly indicate that the high catalytic efficiency with L1 is due to the improvement of the reaction kinetics and not the thermal stability of

Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate

• Michael North and
• Marta Omedes-Pujol

Beilstein J. Org. Chem. 2010, 6, 1043–1055, doi:10.3762/bjoc.6.119

• reaction kinetics showed that complex 2 is active only as mononuclear species in propylene carbonate. Kinetic and NMR studies also showed that the propylene carbonate can coordinate to the vanadium ion of complex 2, thus reducing its Lewis acidity and accounting for the decrease in reaction rate observed

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

• reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid. Keywords: direct electric heating; flow reactors; micro reactors; organic chemistry; reaction kinetics; Introduction Continuously operated small reactors for organic