Synthesis
General procedure: Before each experiment, the solvent needs to be pumped through a tube-in-tube device at 16 bar hydrogen pressure for 30 min to equilibrate the system (cf. Fig. 4). An Omnifit reaction cartridge (20.0 mm outer diameter, 15.0 mm inner diameter) containing 1 g of Pd-C catalyst was used. To prevent overpressurization of the system in case of blockage, the upper pressure of the Knauer pump was set to 25 bar. with the injection loop disconnected from the flow line, the loop was opened and manually (using a syringe) injected with 3.6 mL of a 0.076 M ethanol solution of 3-nitro-4-fluorobenzonitrile (recovering the excess feedstock solution in the loop for reuse). The injection loop was then closed and switched to flow. The system outlet product is collected downstream of the backpressure regulator for 120 minutes. The solvent is removed by distillation under reduced pressure (first using a rotary evaporator and then a two-stage rotary vane pump), resulting in 3-amino-4-fluorobenzonitrile.
References
[1] Tetrahedron, 2018, vol. 74, # 47, p. 6795 - 6803
[2] Patent: US2012/196824, 2012, A1
[3] Patent: WO2011/6935, 2011, A2. Location in patent: Page/Page column 27
[4] Patent: US2008/81802, 2008, A1. Location in patent: Page/Page column 11; 12
[5] Patent: US2013/59846, 2013, A1. Location in patent: Paragraph 0448; 0449; 0450; 0451
