Camera-enabled techniques for organic synthesis

• Steven V. Ley,
• Richard J. Ingham,
• Matthew O’Brien and
• Duncan L. Browne

Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118

• the tube-in-tube reactor. In a recent publication describing the use of ammonia gas in flow synthesis [80], a reversed, “tube-in-tube” reactor configuration was employed whereby the gas was introduced into the semipermeable tubing, while the substrate passed through a second, outer, PTFE tube. This

3D-printed devices for continuous-flow organic chemistry

• Vincenza Dragone,
• Victor Sans,
• Mali H. Rosnes,
• Philip J. Kitson and
• Leroy Cronin

Beilstein J. Org. Chem. 2013, 9, 951–959, doi:10.3762/bjoc.9.109

• the imine reduction processes. All the characteristics of the devices are summarized in Table 1. The 3D-printed devices were integrated in the flow systems using 1.58 mm outer diameter (OD) polytetrafluoroethylene (PTFE) tubing, with an internal diameter of 0.5 mm and standard connectors made of

Synthesis of phenanthridines via palladium-catalyzed picolinamide-directed sequential C–H functionalization

• Ryan Pearson,
• Shuyu Zhang,
• Gang He,
• Nicola Edwards and
• Gong Chen

Beilstein J. Org. Chem. 2013, 9, 891–899, doi:10.3762/bjoc.9.102

• ), and PivOH (6 mg, 0.06 mmol, 0.3 equiv) in anhydrous toluene (4 mL) in a 10 mL glass vial (purged with N2, sealed with PTFE cap) was heated at 120 °C for 24 h. The reaction mixture was filtered through a short pad of celite and concentrated in vacuo. The resulting residue was purified by silica-gel

• : A mixture of picolinamide 3 (70 mg, 0.2 mmol, 1 equiv), Pd(OAc)2 (4.4 mg, 0.02 mmol, 0.1 equiv), PhI(OAc)2 (129 mg, 0.4 mmol, 2.0 equiv), and Cu(OAc)2 (72 mg, 0.4 mmol, 2 equiv) in anhydrous toluene (4 mL) in a 10 mL glass vial (purged with N2, sealed with PTFE cap) was heated at 120 °C for 24 h

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

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

• of bubble-free fluid is ensured in this case by microchannels in at least two levels, which are built from corresponding structured layers. These reactors were made of polyether ether ketone (PEEK) and polytetrafluoroethylene (PTFE) [32] to study the influence of side reactions with the reactor

• regulating the flow speed of the reactant solution, with the help of a syringe pump (Figure 5). For this study, reactors made of PEEK, as well as PTFE reactors were used, leading to similar yields of carbazole (Figure 3 and Figure 4), showing no major influence of the reactor material on the reaction. The

The application of a monolithic triphenylphosphine reagent for conducting Appel reactions in flow microreactors

• Kimberley A. Roper,
• Heiko Lange,
• Anastasios Polyzos,
• Malcolm B. Berry,
• Ian R. Baxendale and
• Steven V. Ley

Beilstein J. Org. Chem. 2011, 7, 1648–1655, doi:10.3762/bjoc.7.194

• dibenzoyl peroxide was then added and the mixture maintained at elevated temperature (50 °C) until the initiator had dissolved (approximately 5 minutes). The mixture was decanted into a glass column and the ends were sealed with custom-made PTFE end pieces. The column was incubated at 92 °C [44][45] for 48

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• pressure of 14 MPa for 3 min. The diffusion layers were prepared by coating a carbon cloth from Ballard (AvCarb 1071HCB) with a layer of 85 wt % carbon black (Ketjen Black EC 300J) and 15 wt % PTFE. A single DMFC test cell was finally assembled from diffusion layers, catalyst coated membrane, bipolar

Koch–Haaf reaction of adamantanols in an acid-tolerant hastelloy-made microreactor

• Takahide Fukuyama,
• Yu Mukai and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2011, 7, 1288–1293, doi:10.3762/bjoc.7.149

• combining an acid-tolerant hastelloy-made micromixer, a PTFE tube, and a hastelloy-made microextraction unit, a packaged reaction-to-workup system was developed. By means of the present system, the multigram scale synthesis of 1-adamantanecarboxylic acid was achieved in ca. one hour operation. Keywords

• sulfuric acid, an acid-tolerant system is essential. For this study, we employed a combination of a hastelloy-made micromixer (MiChS, β-150H) having 150 μm reactant inlet holes and 200 μm × 300 μm channels (Figure 1), and a PTFE tube (1.0 mm i.d. × 3 m, inner volume: 2.36 mL) as a residence time unit. To

• mixture was collected from the outlet. 1-Adamantanol (1a) dissolved in HCOOH (flow rate: 0.30 mL/min) and 98% H2SO4 (flow rate: 0.88 mL/min) were mixed in the micromixer at room temperature, and the resulting reaction mixture was fed into the PTFE tube and then into the extraction unit, in which Et2O

Continuous flow photolysis of aryl azides: Preparation of 3H-azepinones

• Farhan R. Bou-Hamdan,
• François Lévesque,
• Alexander G. O'Brien and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2011, 7, 1124–1129, doi:10.3762/bjoc.7.129

• Vapourtec R2 pump, [50] and mixed by a PTFE T-mixer. Aryl azide 8a bearing a p-methyl ester substituent, prepared by treatment of the corresponding aniline with NaNO2/HCl–NaN3, was selected for initial optimization of the reaction (Scheme 2). During preliminary experiments under the conditions reported by

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• porous PTFE membrane (75 µm thickness). The substrate solution was fed into the anodic chamber and flowed through the membrane into the cathodic chamber, where it would leave as products. The carbon fibre electrodes used in this design allow for a much greater surface area than the empty space between

• the continuous synthesis of diaryliodonium compounds. A microflow electrochemical reactor made out of two aluminium bodies (50 mm diameter, 25 mm height) was manufactured. The electrodes are constructed of two PTFE plates (35 mm diameter, 4 mm height) onto which 0.1 mm platinum foil electrodes [16

Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination

• Jessica R. Breen,
• Graham Sandford,
• Dmitrii S. Yufit,
• Judith A. K. Howard,
• Jonathan Fray and
• Bhairavi Patel

Beilstein J. Org. Chem. 2011, 7, 1048–1054, doi:10.3762/bjoc.7.120

• /liquid–liquid/liquid synthesis of fluoropyrazoles from fluorine, hydrazine and diketone starting materials was constructed from nickel metal and narrow bore PTFE tubing as described previously [28][29] (Figure 1). Briefly, fluorine gas, diluted to 10% v/v solution in nitrogen was added via a mass flow

Unusual behavior in the reactivity of 5-substituted-1H-tetrazoles in a resistively heated microreactor

• Bernhard Gutmann,
• Toma N. Glasnov,
• Tahseen Razzaq,
• Walter Goessler,
• Dominique M. Roberge and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2011, 7, 503–517, doi:10.3762/bjoc.7.59

• concentrations and in different reactor environments, a test reaction was developed that can readily reflect the level of corrosion. For this purpose a 0.5 M solution of nitrobenzene (10) in EtOH containing varying amounts of aqueous conc. HCl (0–1.0 M) was flowed through reactor coils made out of PTFE, SX 316L

• more or less quantitative with respect to HCl after 20 min at 150 °C in a stainless steel coil. Significant reduction to aniline was, however, also observed in a Hastelloy coil under these conditions. As expected, no reduction was experienced in reactor coils made out of chemically inert PTFE, which

• flow reactors were equipped with coils made from different materials (SX 316L steel, Hastelloy C-4 or PTFE), of variable lengths and inner diameters. A system pressure of 140 bar was applied for all experiments in the X-Cube Flash reactor while a pressure of ≈34 bar was selected for all experiments in

Solvent-free phase-vanishing reactions with PTFE (Teflon^®) as a phase screen

• Kevin Pels and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2009, 5, No. 75, doi:10.3762/bjoc.5.75

• Kevin Pels Veljko Dragojlovic Wilkes Honors College of Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458, USA 10.3762/bjoc.5.75 Abstract In a solvent-free phase-vanishing reaction with PTFE (polytetrafluoroethylene, Teflon®) tape as the phase screen, a thermometer adapter is

• utilized to insert a PTFE-sealed tube into the vapor phase above the substrate. Besides avoiding use of solvents, the experimental design is not dependent upon the densities of the reactants and the procedure generates little or no waste while providing the reaction products in high yield and in high

• purity. Keywords: bromination; phase-vanishing; PTFE; solvent-free; stilbene; Findings Phase-vanishing (PV) reactions are triphasic reactions, which involve a reagent, a liquid perfluoroalkane and a substrate [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. In a test tube, a liquid

Synthesis of phosphonate and phostone analogues of ribose-1-phosphates

• Pitak Nasomjai,
• David O'Hagan and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2009, 5, No. 37, doi:10.3762/bjoc.5.37

• ). 19F NMR (282 MHz; MeOH-d4): δ = −234.3 (ddd, 1F, 3JHF = 26.4, 2JHF = 47.4, 2JHF = 47.7). 31P NMR (162 MHz; MeOH-d4): δ = 41.9–42.6 (br, m). νmax (PTFE): 3419, 1214, 1154, 799, 503. HRMS (ES-): Calcd. for C6H9FO5P [M-H]: 211.0172, found: 211.0166. Synthesized phosphonates 8 and 9 and cyclic phostones

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

• HPLC tubing used as flow reactor was made of PTFE with the measurements 1/16 × Ø 0.25 mm. The syringes containing the reagents were connected to the flow system with PEEK adapters (1/4- 28f – Luer, female) and 1/4 PEEK fittings. The T-mixers used were PEEK (1/4-28 with 1/16 fittings and Ø 0.5 mm) for

From discovery to production: Scale- out of continuous flow meso reactors

• Peter Styring and
• Ana I. R. Parracho

Beilstein J. Org. Chem. 2009, 5, No. 29, doi:10.3762/bjoc.5.29

• . Parallel Capillary Reactor The parallel capillary reactor consisted of a capillary block, head space, bottom space inlet manifold, spacer plate, PTFE seal and a packing spacer. Figure 2a shows the schematic of the reactor while Figure 2b is an external photograph of the actual reactor giving an indication

The development and evaluation of a continuous flow process for the lipase- mediated oxidation of alkenes

• Charlotte Wiles,
• Marcus J. Hammond and
• Paul Watts

Beilstein J. Org. Chem. 2009, 5, No. 27, doi:10.3762/bjoc.5.27

• (i.d.) × 3.6 cm (long)) (Omnifit), the immobilised enzyme was held in place using 25 μm polyethylene frits and fluidic connections made using commercially available PEEK and PTFE connectors (Supelco). The flow reactor was heated using a HPLC programmable column heater, containing stainless steel blocks

• filled with a solution containing the alkene under investigation (0.1 M), oxidant (0.2 M) in ethyl acetate and connected to the Omnifit reactor cartridge using PTFE tubing [150 μm (i.d.) × 10 cm (long)] and a PEEK luer connector coupled to a 1/16″ HPLC connector. To the pre-weighed reactor was added

• Novozym® 435 (4, 0.10 g, 26 μl total volume) and the reactor outlet formed from a length of PTFE tubing [150 μm (i.d.) × 5 cm (long)] to enable efficient sampling. The reaction mixture was then pumped through the packed bed (5 to 50 μl min−1) for a period of 30 min, in order to equilibrate, prior to

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

• (unpacked). The coil reactors are made from a selection of materials including PTFE, PEEK, stainless steel or Hastelloy® and accommodate volumes from 2–20 mL. The column reactor (Figure 1, A) can be heated up to 150 °C and the coil heater (Figure 1, B) up to 260 °C, over a range of flow rates between 0.01

Oxidative cyclization of alkenols with Oxone using a miniflow reactor

• Yoichi M. A. Yamada,
• Kaoru Torii and
• Yasuhiro Uozumi

Beilstein J. Org. Chem. 2009, 5, No. 18, doi:10.3762/bjoc.5.18

• oxidative cyclization of (Z)- and (E)-alkenols in i-PrOH with an aqueous solution of Oxone proceeded smoothly and safely in a PTFE tube without any exogenous catalytic species, and was subsequently quenched in a flow-reaction manner to afford the corresponding furanyl and pyranyl carbinols quantitatively

• conventional batch system to a miniflow system. The miniflow reaction system is composed of poly(tetrafluoroethylene) (PTFE) tubes of ø = 1 mm, T-shaped connectors, and syringes with syringe pumps as shown in Figure 1. When the miniflow reaction of the alkenols 1 in i-PrOH with an aqueous solution of Oxone was

• with a flow rate of 4.0 μl/min each by using syringe pumps from the individual inlets. The mixed solution passed through a PTFE tube reactor (length = 50 mm) at 80 °C, and then was quenched with 30% aq Na2S2O3 solution injected into the flow tube with a flow rate of 4.0 μl/min. The resulting organic