To carry out Ugi reactions as quickly and as reproducibly as possible on
small scales for products that precipitate out of methanol.
- Weigh a 2 ml Eppendorf tube and write weight on the tube
- Fill with 500 microliters of methanol
- Add 500 micromoles of amine, aldehyde, acid and isonitrile in that
order. After each addition, vortex for 15 seconds and confirm that a
homogeneous solution has been obtained. If a clear solution is not obtained
at any point abort.
- Leave tube at room temperature for 24 hours.
- Note the presence of a precipitate then vortex for 15 seconds.
- Centrifuge at x RPM for 60 seconds then discard supernatant.
- Add 500 microliters of methanol, vortex for 15 seconds then
centrifuge at x RPM for 60 seconds.
- Repeat the washing procedure for a total of 3 washes.
- Put open tube under high vac for 15 minutes.
- Record weight and obtain H and C NMR of entire sample in
- Submit small sample for MS analysis.
- Amine and Aldehyde can be mixed and left for 3 hours before
addition of acid and isonitrile to see if it makes any difference.
- One dram vials can be used instead of Eppendorf tubes.
- Use vortexing or sonication to induce precipitation.