Figure 1. (a) Schematic set-up of the packed-bed resin-N3 flow
device. (b) Azidation of benzyl chloride with resin-N3at different temperatures and different runs, with 0.1 ml/min flow rate.
The plot reports the conversion obtained when the
resin-N3 was reused three times, the total volume of
benzyl chloride passed through the resin bed at the optimized conditions
was 18 mL (6 mL per each use). This resulted in a total production of
2,6-difluorobenzyl azide of 3.0 g at 80°C (average conversion 99.5 ±
0.4%) and 2.5 g at 65°C (average conversion 82.6 ± 3.1%).
For the second reaction, Cu-bis(oxazoline) loaded cross-linked
polymersomes were employed as a nanosized reactor and separator. These
functionalized polymersomes were successfully applied previously for a
Cu (II) catalyzed cyclopropanation reaction at r.t. in a batch
reactor,17 but were
never exploited before in a CuAAC reaction toward the synthesis of
pharmaceuticals. The objective of introducing polymersomes in this
microflow process was to integrate the two-step synthetic procedure into
one step, and to protect the Cu (I) catalyst, positioned in the bilayer
membrane from undesired interactions with the azide ion.