Objective

To monitor the reaction of the imine formed with an acid (amino or carboxylic acid).

Steps

  1. Make up separate 1 mL of 1M solutions of any aromatic aldehyde, any amine and any acid in MeOH-d4.
  2. Take HMRs and CMRs of the aldehyde, acid and amine separately.
  3. Combine the aldehyde and amine solutions into a 1 dram vial and shake vigorously then transfer to an NMR tube.
  4. Take HMR at 5, 10 and 20 minutes after mixing.
  5. Take CMR at 25 min after mixing.
  6. Take HMR at 40 min after mixing.
  7. Take CMR at 45 min after mixing.
  8. Take HMR at 80 mins after mixing.
  9. Take CMR at 85 mins after mixing.
  10. Continue to take NMRs after interval doubling until no more change is observed.
  11. Remove water with MgSO4, or any other means.
  12. Filter if nesessary depending on technique used.
  13. Add prepared acid solution to imine solution and shake.
  14. Take HMR at 5, 10 and 20 minutes after mixing.
  15. Take CMR at 25 min after mixing.
  16. Take HMR at 40 min after mixing.
  17. Take CMR at 45 min after mixing.
  18. Take HMR at 80 mins after mixing.
  19. Take CMR at 85 mins after mixing.
  20. Continue to take NMRs after interval doubling until no more change is observed.

Vatiations

Other NMR solvents that we have seen to work in our experiments or other papers (eg CDCl3, DMSO, etc).
All amine and aromatic aldehyde combinations.