Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• system for purifications of an immobilized enzyme-based reaction. Redrawn from [54]. Countercurrent L–L purification using large Zaiput membranes in the presence of a phase transfer catalyst (PTC). Redrawn from [55]. General scheme of a telescoped flow process using L–L separators. Example of phase

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• esters with mainly fruity odor profiles are obtained in moderate to excellent yields. Some selected esters (14–16) and their odor profiles are shown in Scheme 4 [32]. Related methods for the esterification of natural occurring alcohols, such as geraniol, utilizing immobilized enzyme-catalysis in packed

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• experiments. Furthermore, the most suited carrier with immobilized enzyme was analyzed in long-term studies with respect to the stability of the enzyme preparation. The enzymes were immobilized on six different carriers according to the instructions of the supplier (Lifetech Purolite, Ratingen, Germany). The

• immobilized enzymes during storage and application is an important criterion for the economic use of the enzyme. Therefore, immobilized enzyme aliquots were stored under four different conditions: filtered and cooled at 6 °C, with buffer at 6 °C, with buffer at 40 °C, and with buffer at 40 °C and shaking at

• sizes (600–1200 nm) that was used for the aldolase immobilization, suggesting that the residual content of moisture significantly influences the stability of the immobilized enzyme. The strongest influence on the stability is evoked by the heating of the immobilized enzymes. A reduction of the half-life

Selective enzymatic esterification of lignin model compounds in the ball mill

• Ulla Weißbach,
• Saumya Dabral,
• Laure Konnert,
• Carsten Bolm and
• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1788–1795, doi:10.3762/bjoc.13.173

• -1a with CALB in the ball mill A mixture of erythro-1a (50 mg, 0.15 mmol), acyl donor 2 (0.60 mmol) and CALB (30 mg of the immobilized enzyme) was milled for 2 h to 6 h at 30 Hz in a 10 mL ZrO2 milling jar loaded with 6 ZrO2 milling balls (5 mm in diameter). After the milling was stopped, the reaction

• erythro-1a with isopropenyl acetate (2a) in the ball mill. Reaction conditions: erythro-1a (50 mg, 0.15 mmol), 2a (0.60 mmol), CALB (30 mg of immobilized enzyme) or NaOH (12 mg, 0.30 mmol), 10 mL ZrO2 milling jar, 6 ZrO2 milling balls (5 mm in diameter). CALB-catalyzed esterification of lignin model

Highly stable and reusable immobilized formate dehydrogenases: Promising biocatalysts for in situ regeneration of NADH

• Barış Binay,
• Dilek Alagöz,
• Deniz Yildirim,
• Ayhan Çelik and
• S. Seyhan Tükel

Beilstein J. Org. Chem. 2016, 12, 271–277, doi:10.3762/bjoc.12.29

• immobilized enzyme is the type of binding groups on the support which provides higher loading of enzyme and higher retention of activity [28]. Epoxy group containing supports are widely used in the immobilization of many enzymes through multi-point covalent attachments since epoxy groups can easily react with

Flow synthesis of phenylserine using threonine aldolase immobilized on Eupergit support

• Jagdish D. Tibhe,
• Hui Fu,
• Timothy Noël,
• Qi Wang,
• Jan Meuldijk and
• Volker Hessel

Beilstein J. Org. Chem. 2013, 9, 2168–2179, doi:10.3762/bjoc.9.254

• rationalized by the natural equilibrium as well as product inhibition which was experimentally proven. The flow synthesis with the immobilized enzyme was compared with the corresponding transformation conducted with the free enzyme. The product yield was further improved by operating under slug flow conditions

• was achieved at 20 minute residence time. Finally, the productivity of the reactor was calculated, extrapolated to parallel run units, and compared with data collected previously. Keywords: Eupergit; flow chemistry; immobilized enzyme; threonine aldolase; Introduction Enzymes are bio-based catalysts

• ]. The above mentioned drawbacks may also be largely avoided by the use of an immobilized enzyme [4]. Immobilization has also been shown to enhance the stability of the enzyme [5]. A number of different immobilization methods were reviewed by Sheldon [6]. Despite the many advantages to use enzymes, their

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

• mL·min–1, H2:substrate ratio = 4). The racemic alcohol (75% conversion for the first step) was directly fed to a second catalytic reactor containing the supported biocatalyst to carry out the kinetic resolution (40–50 °C, Novozym 435 or CLEAS as the immobilized enzyme). Although only moderate conversions

Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems

• Gernot U. Marten,
• Thorsten Gelbrich and
• Annette M. Schmidt

Beilstein J. Org. Chem. 2010, 6, 922–931, doi:10.3762/bjoc.6.98

• of free trypsin, and redispersed in HEPES buffer. Determination of immobilized enzyme kinetics and activity: BAPNA was used as the model substrate. Four HEPES buffered BAPNA solutions with concentrations between 2.0 mM and 0.5 mM, and a 6.0 μM trypsin solution were prepared and tempered to the

N-acylation of ethanolamine using lipase: a chemoselective catalyst

• Mazaahir Kidwai,
• Roona Poddar and
• Poonam Mothsra

Beilstein J. Org. Chem. 2009, 5, No. 10, doi:10.3762/bjoc.5.10

• support method In an Erlenmeyer flask, fatty acids 1a–d and ethanolamine (2) were dissolved in minimum amount of solvent and impregnated on immobilized enzyme by subsequent evaporation under vacuum. Now enzyme-free carrier material was taken in beaker with dummy load and the reactions were performed in an

• amount of reaction mixture (0.5 mL for conventional, 0.1 mL for solution phase and 0.05 g for solid support) was taken out and diluted with methanol and chloroform [50:50 (v/v)]. The immobilized enzyme was removed from reaction mixture via filtration and the reaction mixture made up to the final

Large- scale ruthenium- and enzyme- catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol

• Krisztián Bogár,
• Belén Martín-Matute and
• Jan-E. Bäckvall

Beilstein J. Org. Chem. 2007, 3, No. 50, doi:10.1186/1860-5397-3-50

• racemization of 1-phenylethanol (2) in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In