A flow reactor setup for photochemistry of biphasic gas/liquid reactions

• Josef Schachtner,
• Patrick Bayer and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170

• majority of applications of microflow setups involved reagents in the same aggregation state (homogeneous, mostly liquid phase). In contrast, an especially complex problem beyond the scope of most microreactor setups are heterogeneous reactions [31][32] between three dispersed entities such as a liquid

• , O3, H2, Cl2, acetylene, NOx, CO, CO2, etc.) but obviously bear several challenges with regard to a reproducible and precise control of the addition and mixing of the three phases: the liquid phase, containing organic substrates, the photo-active component (catalyst or sensitizer), the solvent, and

• attention should be directed at the homogeneity of the liquid phase in case of, e.g., limited solubility or biphasic systems which might require the addition of a co-solvent, prior filtration of the solution phase, or the installation of an upstream filter. It is important to consider that most HPLC pumps

Flow carbonylation of sterically hindered ortho-substituted iodoarenes

• Carl J. Mallia,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1503–1511, doi:10.3762/bjoc.12.147

• an important characteristic when gases are involved as this is an essential factor determining the solubility of a gas in the liquid phase. The interfacial area is generally very small when traditional batch chemistry equipment is used such as round bottom flasks. This also becomes proportionally

• the gases in the liquid phase. In our work a reverse “tube-in-tube” reactor [31][32][33] was used to deliver the carbon monoxide to the reaction (Figure 3), as this was shown to be more efficient than an alternative plug flow system (Scheme 1) when evaluated on iodobenzene (2). The “tube-in-tube” gas

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• milling conditions favours SN2 reactions; however it is also true that a solventless environment does not necessarily mean that there is a lack of solution in a liquid phase. Some reaction mixture components can often be liquid, while solvent effects or mixed SN2 and SN1-type reaction mechanisms cannot be

Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

• Hynek Balcar,
• Naděžda Žilková,
• Martin Kubů,
• Michal Mazur,
• Zdeněk Bastl and
• Jiří Čejka

Beilstein J. Org. Chem. 2015, 11, 2087–2096, doi:10.3762/bjoc.11.225

• earlier [21]. In contrast to that, the atomic ratio Cl/Ru = 1.9 for HGIIN+Cl−/MCM-22 may indicate that Cl− remained in a liquid phase as NaCl. For HGIIN+PF6−/MCM-22 catalyst, the results suggest that reduction of the PF6 anion to the PF3 species took place in immobilized compound. In addition to it, the

• were studied in RCM of (−)-β-citronellene. Figure 4 shows a splitting test [33] for HGIIN+Cl−/MCM-56. 10 min after the beginning of the reaction, a half of the liquid phase was filtered off into a parallel reactor further kept under the same reaction temperature. Metathesis reaction continued in the

• heterogeneous system only, which evidences no leaching of catalytically active species into the liquid phase. Ru leaching determined by elemental analysis in the reaction mixture after finishing the reaction was 0.3%, 0.1%, and 0.6% of starting amount of Ru in catalyst for HGIIN+Cl−/MCM-22, HGIIN+Cl−/MCM-56

Grubbs–Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

• Maximilian Koy,
• Hagen J. Altmann,
• Benjamin Autenrieth,
• Wolfgang Frey and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2015, 11, 1632–1638, doi:10.3762/bjoc.11.178

• applying supported ionic liquid phase (SILP) technology [11]. We recently reported on different Ru-based ionic metathesis catalysts that can be used for these purposes. In these systems, the charge is either located directly at the ruthenium [11][12] or at the 1-methylpyridinium-4-carboxylate ligands that

Synthesis and evaluation of the biostability and cell compatibility of novel conjugates of nucleobase, peptidic epitope, and saccharide

• Dan Yuan,
• Xuewen Du,
• Junfeng Shi,
• Ning Zhou,
• Abdulgader Ahmed Baoum,
• Khalid Omar Al Footy,
• Khadija Omar Badahdah and
• Bing Xu

Beilstein J. Org. Chem. 2015, 11, 1352–1359, doi:10.3762/bjoc.11.145

• ]. The conjugates NAS were produced by a combination of SPPS and liquid phase synthesis. Scheme 2 shows a representative synthesis route of a NAS conjugate (1). We loaded the first amino acid, Fmoc-Val-OH, on 2-chlorotrityl chloride resin, then removed the Fmoc group with 20% piperidine in

• solid-phase peptide synthesis and liquid-phase synthesis). i) Fmoc-Val-OH, DIPEA; ii) 20% piperidine; iii) Fmoc-Pro-OH, HBTU, DIPEA; iv) Fmoc-Thr(t-Bu)-OH, HBTU, DIPEA; v) thymine-1-acetic acid, HBTU, DIPEA; vi) TFE/DCM 2:8; vii) D-glucosamine hydrochloride, HBTU, DIPEA; viii) TFA/H2O 95:5

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• ; c) TMSCF3, RMS 79 pm. The experimental set-up for the dibromo-, dichloro- and difluorocarbene reactions performed on C11-vinyl SAMs. Model reactions of dec-1-ene (1) with dihalocarbenes in the liquid phase. a) and b) NaOH, BTEAC, CHX3, DCM, 8 h, 25 °C; c) TMSCF3, THF, NaI, 3 h, 65 °C. Assignment of

Synthesis of novel conjugates of a saccharide, amino acids, nucleobase and the evaluation of their cell compatibility

• Dan Yuan,
• Xuewen Du,
• Junfeng Shi,
• Ning Zhou,
• Abdulgader Ahmed Baoum and
• Bing Xu

Beilstein J. Org. Chem. 2014, 10, 2406–2413, doi:10.3762/bjoc.10.250

• the peptide segment (Phe-Arg-Gly-Asp or naphthAla-Phe-Arg-Gly-Asp with fully protected groups), and later, an amidation reaction in liquid phase connects these three parts together. The overall yield of these multiple step synthesis is about 34%. Besides exhibiting excellent solubility, these

Solution phase synthesis of short oligoribonucleotides on a precipitative tetrapodal support

• Alejandro Gimenez Molina,
• Amit M. Jabgunde,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2014, 10, 2279–2285, doi:10.3762/bjoc.10.237

• support-bound oligonucleotides precipitated quantitatively from MeOH, while the unreacted building block and small molecular reagents remained in the filtrate (Figure 1). No sign of the HPLC signal referring to the support bound nucleotides (tR = 20.14 min) could be detected in the liquid phase. In

Bis(β-lactosyl)-[60]fullerene as novel class of glycolipids useful for the detection and the decontamination of biological toxins of the Ricinus communis family

• Hirofumi Dohi,
• Takeru Kanazawa,
• Akihiro Saito,
• Keita Sato,
• Hirotaka Uzawa,
• Yasuo Seto and
• Yoshihiro Nishida

Beilstein J. Org. Chem. 2014, 10, 1504–1512, doi:10.3762/bjoc.10.155

• undertook an alternative way by means of the SDS-PAGE. The results summarized in Table 1 show that the ricin protein was partitioned into two phases, i.e., solid phase (precipitates) and liquid phase (supernatants), after the sedimentation. Its distribution (%) in the solid phase increased with the

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• -pentadienylpiperidines. The structures of the streptopyridines A to E were confirmed by total synthesis. The analysis of the liquid phase by solvent extraction or extraction with an Oasis adsorbent showed that streptazolin and 2-pentadienylpiperidine are the major compounds, while the streptopyridines are only minor

• structure verification. Agar plate cultures and liquid cultures were investigated and the liquid phase analyzed for the presence of secondary metabolites. The results showed that by headspace analysis new secondary metabolites can be found that eluded earlier analysis. The separate analysis of headspace and

• liquid phase is complementary and in combination allows better evaluation of the metabolic potential of an investigated microorganism. Results and Discussion The volatiles released by agar plate cultures of strain Streptomyces sp. FORM5 were collected by CLSA for one day on a charcoal filter and eluted

Biantennary oligoglycines and glyco-oligoglycines self-associating in aqueous medium

• Svetlana V. Tsygankova,
• Alexander A. Chinarev,
• Alexander B. Tuzikov,
• Nikolai Severin,
• Alexey A. Kalachev,
• Juergen P. Rabe,
• Alexandra S. Gambaryan and
• Nicolai V. Bovin

Beilstein J. Org. Chem. 2014, 10, 1372–1382, doi:10.3762/bjoc.10.140

• times insufficient for a spontaneous association in solution (found out as ≤1 min). The solution was placed on a freshly cleaved surface of mica or graphite, exposed for fixed time intervals (denoted as texp), followed by the removal of the liquid phase from the surface and the scanning of the sample in

• biantennary oligoglycines in neutral and basic solutions. Layer growth proceeds due to the surface co-participation. In the case of the molecule Н-Gly4-NH(СН2)10NH-Gly4-Н growth continues until the surface is completely covered, whereas in the bulk of the liquid phase dimensions remain unchanged over time

• comparison of association of all investigated peptides. The association in the liquid phase proceeds slower at low concentrations leading to an increased size of the formed supramers. In summary, based on our investigations related to unglycosylated molecules we can conclude that the association of

Solid-phase-supported synthesis of morpholinoglycine oligonucleotide mimics

• Tatyana V. Abramova,
• Sergey S. Belov,
• Yulia V. Tarasenko and
• Vladimir N. Silnikov

Beilstein J. Org. Chem. 2014, 10, 1151–1158, doi:10.3762/bjoc.10.115

• ) and liquid phase synthesis (B); the blunt end of MorGly oligomer (C). Cleavage of MorGly oligonucleotide mimics from solid support and deprotection of nucleobases by aqueous ammonia treatment: i) NH3/H2O. MorGly homopentamers containing adenine, uracil, and thymine nucleobases. Synthesis of Boc

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• with in terms of the sustainability of individual processes a few large scale consortia have focused on continuous flow nitration using miniaturized devices [20][21]. An analysis of the literature shows that as many as 45% of the nitrations are for liquid phase systems both homogeneous (miscible) and

• activity. The presence of multiple phases clearly indicates the choice of substrates explored in the nitrations reported so far and the use of solvents for specific substrates, mainly to maintain the system in liquid phase (although immiscible). More details on the selection of the experimental setup will

• shown in Figure 2. In Table 1 specific parameters are shown to provide a firsthand overview of the typical conditions and setups. In general, the heat of reaction for all of them ranges from −73 to −253 kJ/mol, and almost all substrates are in liquid phase, propane being the sole exception. Typical

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

• Ludovic Eberlin,
• Fabien Tripoteau,
• François Carreaux,
• Andrew Whiting and
• Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

• these results obtained in the liquid phase, Hall and co-workers also examined the suitability of a solid-phase strategy. Finally, due to problems of purity encountered with an N-arylmaleidobenzoic acid-functionalized resin [70], or availability of the supported aldehyde partner, a four-component variant

Synthesis of nucleotide–amino acid conjugates designed for photo-CIDNP experiments by a phosphotriester approach

• Tatyana V. Abramova,
• Olga B. Morozova,
• Vladimir N. Silnikov and
• Alexandra V. Yurkovskaya

Beilstein J. Org. Chem. 2013, 9, 2898–2909, doi:10.3762/bjoc.9.326

• phosphotriester block liquid phase synthesis. The phosphotriester approach to the oligonucleotide synthesis was shown to be a versatile and economic strategy for preparing the required amount of high quality samples of nucleotide–amino acid conjugates. Keywords: CIDNP; nucleotide–amino acid conjugates

• conjugates consisting of amino acid, nucleotide, and dye residues including linkers of different lengths (Figure 1). Target compounds 1–8 have been synthesized by the phosphotriester block liquid phase synthesis (LPS). Results and Discussion Design of model compounds Our previous studies revealed a great

• standards, the use of the hyperpolarization approach is extraordinary to elucidate the interactions between hidden transient intermediates of nucleosides and amino acids in conjugates, which mimic biologically relevant processes. The liquid phase synthesis (LPS) in combination with the phosphotriester

Ethyl diazoacetate synthesis in flow

• Mariëlle M. E. Delville,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 1813–1818, doi:10.3762/bjoc.9.211

• attached to guarantee a liquid phase even above boiling temperatures of the solvents. To ensure well-defined reaction times during optimization experiments, neat N,N-diisopropylethylamine (DIPEA) was added via syringe 4 to efficiently quench the reaction. The collected product (60 μmol) was analyzed by

Photochemistry with laser radiation in condensed phase using miniaturized photoreactors

• Elke Bremus-Köbberling,
• Arnold Gillner,
• Frank Avemaria,
• Céline Réthoré and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1213–1218, doi:10.3762/bjoc.8.135

• as for demanding reaction conditions, such as the rapid elevation of temperature (with pulsed IR-laser radiation) or pressure pulses (due to the evaporation of the solvent upon the introduction of energy). Several microstructured reactor types were designed and produced for reactions in the liquid

• phase. They are equipped with quartz-glass cover plates, transparent to the laser radiation, pressed onto an appropriate sealing material. Moreover, channels suitable for the mixing and reaction of two or more isopycnic solutions were built in a polymer bloc by mechanical treatment [31]. The provision

Synthesis of diverse indole libraries on polystyrene resin – Scope and limitations of an organometallic reaction on solid supports

• Kerstin Knepper,
• Sylvia Vanderheiden and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1191–1199, doi:10.3762/bjoc.8.132

• results in the liquid phase, ortho,ortho-unsubstituted nitroarenes also delivered indole moieties in good yields. Subsequent palladium-catalyzed reactions (Suzuki, Heck, Sonogashira, Stille) delivered, after cleavage, the desired molecules in moderate to good yields over four steps. The scope and

• contrast to their liquid-phase counterparts. However, they gave a mixture of products (Supporting Information File 1). The next stage is the functionalization by cross-coupling reactions. In our first communication, we employed Suzuki and Heck reactions [24]. In addition to these reactions, Stille

Liquid-crystalline heterodimesogens and ABA-heterotrimesogens comprising a bent 3,5-diphenyl-1,2,4-oxadiazole central unit

• Govindaswamy Shanker,
• Marko Prehm and
• Carsten Tschierske

Beilstein J. Org. Chem. 2012, 8, 472–485, doi:10.3762/bjoc.8.54

• ). Upon cooling of these compounds from the isotropic liquid phase, Schlieren textures were observed, which are evidence of nematic phases [68][69]. These trimesogens have very high clearing temperatures at around T = 320 °C for compound CB-Ox-CB/3 and at T = 245 °C for CB-Ox-CB/4. The major reason for

Biocatalytic hydroxylation of n-butane with in situ cofactor regeneration at low temperature and under normal pressure

• Svenja Staudt,
• Christina A. Müller,
• Jan Marienhagen,
• Christian Böing,
• Stefan Buchholz,
• Ulrich Schwaneberg and
• Harald Gröger

Beilstein J. Org. Chem. 2012, 8, 186–191, doi:10.3762/bjoc.8.20

• concentration of n-butane in the liquid phase at a reasonable level (at least over a certain period of time, which is dependent also on the volume of the gas phase). Results and Discussion For our initial study of the ability of the P450-monooxygenase to exhibit sufficient activity even at a decreased reaction

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

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

• and were dissolved in the liquid phase containing the whole cells and other nutrients required for the cell growth. The product was again removed in the gas phase and collected in a saturator/absorber module. By supplying and removing substrates and products by transfer to the gas phase, problems

Translation of microwave methodology to continuous flow for the efficient synthesis of diaryl ethers via a base-mediated S_NAr reaction

• Charlotte Wiles and
• Paul Watts

Beilstein J. Org. Chem. 2011, 7, 1360–1371, doi:10.3762/bjoc.7.160

• is maintained under a back pressure of 25 bar, which enables reactants and solvents to be heated above their atmospheric boiling point whilst staying in the liquid phase. The reactant flow rates, reactor temperature and sample collection point is automated and the system has an in-line pressure

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

• more than threefold improved STYs. Statistical methods and a thorough study of the phase behavior were used to optimize the system. Optimum conditions were located just below the critical point of the mixture in an expanded liquid phase regime. High reaction rates corresponding to TOF values of 500–800

• was attributed to their inclusion in hydrophilic gaps of the network, where they are surrounded by a strong ionic net. The extremely ordered supramolecular structure of the ILs in the liquid phase may be able to act as a “mould”, maintaining the active 3D structure of the enzyme and avoiding unfolding