Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• (Scheme 1). Retention of the cofactor was achieved by its covalent binding to polyethylene glycol (PEG) with a molecular weight of 10 kDa. The reactor was operated continuously for 48 days under sterile conditions. A maximal conversion of 99.7% and a space-time yield (STY) of 42.5 g L−1 day−1 were reached

• was used for cofactor regeneration, and immobilization of NADH on PEG prevented loss of the cofactor in the continuously operated reactor. Space-time yields of 700 g L−1 day−1 were achieved with the optimized reactor at 95% conversion. Deactivation of enzyme and PEG–NADH led to a decrease of

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

• provide simple tools for a rapid optimization of reaction parameters and facilitate the development of efficient flow processes [23][24][25]. Neoteric solvents (scFs, ionic liquids, PEG, etc.) have been considered as “green” alternative solvents due to their properties. However, in order to consider a

• below the detection limit of 1 ppm [52]. c) Catalysts immobilized in other liquid phases Other unconventional solvents such as fluorous solvents, polyethyleneglycol (PEG) or water were also used in a manner similar to that described above for ILs [19]. An example is the hydrogenation of itaconic acid or

• improvement of the system, the same authors reported the coupling of the resolution step with the continuous separation of the two products formed based on their different solubilities in the scCO2 phase [101]. Reetz et al. also extended this methodology to a biphasic polyethyleneglycol (PEG)/scCO2 system

PEG-embedded KBr₃: A recyclable catalyst for multicomponent coupling reaction for the efficient synthesis of functionalized piperidines

• Sanny Verma,
• Suman L. Jain and
• Bir Sain

Beilstein J. Org. Chem. 2011, 7, 1334–1341, doi:10.3762/bjoc.7.157

• Sanny Verma Suman L. Jain Bir Sain Chemical Sciences Division, Indian Institute of Petroleum (Council of Scientific and Industrial Research), Dehradun-248005, India 10.3762/bjoc.7.157 Abstract PEG-embedded potassium tribromide ([K+PEG]Br3−) was found to be an efficient and recyclable catalyst for

• the synthesis of functionalized piperidines in high yields in a one step, three component coupling between aldehyde, amine and β-keto ester. At the end of the reaction the [K+PEG]Br3− was readily regenerated from the reaction mixture by treating the residue containing [K+PEG]Br− with molecular bromine

• accessible catalytic protocol for the synthesis of functionalized piperidines by the one-pot coupling of aldehyde, amine and β-keto ester with PEG-wrapped KBr3 as a recyclable catalyst. The PEG-embedded tribromide could easily be synthesized through the concept of host–guest complexation [34] of PEGs with

Nano copper oxide catalyzed synthesis of symmetrical diaryl sulfides under ligand free conditions

• K. Harsha Vardhan Reddy,
• V. Prakash Reddy,
• A. Ashwan Kumar,
• G. Kranthi and
• Y.V.D. Nageswar

Beilstein J. Org. Chem. 2011, 7, 886–891, doi:10.3762/bjoc.7.101

• 4, 5). Other bases such as K2CO3 and K3PO4 gave lesser amounts of the desired product (Table 1, entries 3, 6). Among the solvents, DMSO yielded the best results (Table 1, entry 5) whereas PEG and DMF gave the products in moderate yields (Table 1, entries 9 and 10), whilst solvents such as toluene

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• from polyisoprene and that these can be further crosslinked. Latexes with double functionality were also prepared by the free-radical polymerization of divinylbenzene in miniemulsion [46][47]. The remaining vinyl group after polymerization could be, for instance, reacted with thiol-functionalized PEG

• presence of methoxypoly(ethylene glycol) with the same oil used by Altinbas et al. [86]. Based on FT-IR and 1H NMR measurements, the authors claimed that poly(ethylene gycol) (PEG) chains were connected to the poly(n-butyl cyanoacrylate). The same approach has been used by other authors with other surface

• active initiators based on PEG [87]. The hydrophilic layer thickness and surface coverage of non-dialyzed nanoparticles were estimated for various surfactant concentrations [88]. The investigation was carried out by the same group with a modified dextran as stabilizer [89]. An unconventional approach was

Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s

• Richard Hoogenboom,
• Martin W. M. Fijten,
• Guido Kickelbick and
• Ulrich S. Schubert

Beilstein J. Org. Chem. 2010, 6, 773–783, doi:10.3762/bjoc.6.96

• pump, a 2414 refractive index detector and a Waters Styragel HT4 column utilizing DMF containing 5 mM NH4PF6 at a flow rate of 0.5 mL/min as eluent and the column oven set to 50 °C (PEG calibration). MALDI-TOF-MS was performed on a Voyager-DE™ PRO Biospectrometry™ Workstation (Applied Biosystems) time

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length

• Florian K. Wolf,
• Anna M. Fischer and
• Holger Frey

Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67

• ]. Their potential arises from their ability to encapsulate and release hydrophilic molecules slowly. Particularly, PEG/PLA-based copolymers have been intensely studied in this context [11][12][13]. Apart from this special application in solution, analogs of well-known linear polymers with star

• via calibration with polyethylene glycol (PEG) standards. The obvious underestimation of the molecular weight by SEC is attributed to the peculiar spherical geometry of the multi-arm star copolymer and has also been observed with other star polymers. The polydispersities of the materials are in the

New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

• Otman Otman,
• Paul Boullanger,
• Eric Drockenmuller and
• Thierry Hamaide

Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58

• concentration of free surfactant in the aqueous phase. The hydrophilic part is most often constructed from PEG chains. In addition to the steric stabilization, this PEG coating reduces the detection of particles or liposomes by the immune system and consequently, the reticular endothelial uptake of

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

• low pressure applications. The third syringe was loaded on a separate syringe pump. The flow rate was adjusted to an overall flow rate of 7.5 µL/min. The source of heating for the reaction was a PEG 600 oil bath. After passing the heating zone (80 °C) behind the second T-junction (4 m) the reaction

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• water solubility more generally, aryl modified phosphonium salts, carrying a –COOH group [38] or PEG attachments [39], have been developed but require extensive synthetic work. Previously, non-stabilized alkylphosphonium salts have appeared much less amenable than the benzyl analogues. A single paper

• alkyl bromide precursors are not available (Scheme 1). 5a was readily synthesised by Swern-type oxidation (see Supporting Information File 1). The Wittig reagents were poorly soluble in water. Nevertheless, functional groups enhancing their solubility, such as previously reported –COOH or PEG