Continuous N-alkylation reactions of amino alcohols using γ-Al₂O₃ and supercritical CO₂: unexpected formation of cyclic ureas and urethanes by reaction with CO₂

• Emilia S. Streng,
• Darren S. Lee,
• Michael W. George and
• Martyn Poliakoff

Beilstein J. Org. Chem. 2017, 13, 329–337, doi:10.3762/bjoc.13.36

• could be synthesised by incorporation of CO2 from the supercritical solvent into the product. Keywords: continuous flow; heterocycle; N-alkylation; self-optimisation; supercritical CO2; Introduction N-alkylated amines are an important motif present in a range of pharmaceutically and industrially

• alcohols using γ-Al2O3 with scCO2 as the solvent and employed self-optimisation [45][46] to explore the defined parameter space to effectively identify the highest yielding and optimal conditions in a relatively short timeframe. Results and Discussion To investigate our hypothesis that γ-Al2O3 with scCO2

• ). For this reaction, self-optimisation is important as multiple products were identified that could form in parallel; from 1 the possible products we expected to see were a mixture of piperidine (2a), N-methylpiperidine (2b), N- and O-methylated 1, as well as oligomers. We chose to target 2b only for

Self-optimisation and model-based design of experiments for developing a C–H activation flow process

• Alexander Echtermeyer,
• Yehia Amar,
• Jacek Zakrzewski and
• Alexei Lapkin

Beilstein J. Org. Chem. 2017, 13, 150–163, doi:10.3762/bjoc.13.18

• recently described C(sp3)–H activation reaction to synthesise aziridines was used as a model reaction to demonstrate the methodology of developing a process model using model-based design of experiments (MBDoE) and self-optimisation approaches in flow. The two approaches are compared in terms of

• experimental efficiency. The self-optimisation approach required the least number of experiments to reach the specified objectives of cost and product yield, whereas the MBDoE approach enabled a rapid generation of a process model. Keywords: automated reaction system; C–H activation; design of experiments

• ; flow chemistry; process modelling; self-optimisation; Introduction The development of manufacturing processes to produce functional molecules, such as pharmaceuticals or fine chemicals, often relies on experience and trial-and-error, rather than on mechanistic process models [1]. The only reason for