Objective

To synthesize a ugi product using tert-butylamine, benzaldehyde, tert-butyl isocyanide and Boc-Gly-OH.

Procedure

A solution of benzaldehyde (212 uL, 2 mmol) and tert-butylamine (231.18 uL, 2.2 mmol, 10% excess) was made in methanol in a 4 mL volumetric flask. The solution was immediately transferred to a 25 mL Erlenmeyer flask. The reaction mixture was allowed to sit for about 6 hours without stirring to form the imine.
A solution of Boc-Gly-OH(350 mg, 2 mmol), and tert-butyl isocyanide (226 uL, 2 mmol) was made up in 4 ml volutmeric flask in methanol. This solution was added to the preformed Imine solution. The reaction mixture was allowed to sit undisturbed overnight, when a crystalline Ugi product was obtained which was filtered and washed with cold methanol. The crystalline product was saved in a vial.

Results

tert-butylamine
H NMR (methyls at 1.15 ppm and amine at 1.20 )
C NMR
Benzaldehyde
H NMR
C NMR
tert-butyl isocyanide
H NMR
C NMR
Boc-Gly-OH
H NMR
C NMR
089A
H NMR

Discussion

  1. From the H NMR of 089A, it is evident there is a substantial amount of aldehyde still remaining in the reaction, this is unlike the previous reactions (Exp086, etc) where the final product hardly contained any aldehyde. Since the aldehydes we are using are fully soluble at the concentration used in our Ugi reactions, there should never be any aldehyde in the final Ugi product obtained by filtration. In this experiment, the solvent was allowed to evaporate.


Conclusion

This experiment was aborted because the reaction mixture was accidentally left to evaporate to dryness.

Log

2007-04-04

12:20 Made up a solution of benzaldehyde and tert-butylamine in methanol (4 mL)
17:30 Made up a solution of Boc-glycine and t-butyl isocyanide in 4 mL methanol (2 mmol each)
17:40 Added t-butylisocyanide and boc-glycine solution in methanol to the previously made benzaldehyde in t-butylamine solution.

2007-04-05

16:40 Only a few crystals have accumulated on the walls of the erlenmeyer flask. The reaction does not seem to have gone smoothly as in Exp086

2007-04-07

14:00 The erlenmeyer had been left in the fume hood without a stopper, as a result, methanol (the solvent) evaporated and some solid had appeared at the bottom of the erlenmeyer flask,
14:30 The solid was removed with cold methanol and filtered. 089A (76.7 mg) was obtained.
15:00 The solid was air dired and then let sit in a vacuum dessicator for about an hour.
17:00 Obtained H NMR of 089A


Tags

benzaldehyde InChI=1/C7H6O/c8-6-7-4-2-1-3-5-7/h1-6H
tert-butylamine InChI=1/C4H11N/c1-4(2,3)5/h5H2,1-3H3
Boc-Gly-OH InChI=1/C7H13NO4/c1-7(2,3)12-6(11)8-4-5(9)10/h4H2,1-3H3,(H,8,11)(H,9,10)
tert-butyl isocyanide InChI=1/C5H9N/c1-5(2,3)6-4/h1-3H3