Researchers

Hai & Khalid

Objective

To determine the solubility of UCExp251-1C (176C) in a) benzene, b) 0.1M phenananthrene-9-carboxaldehyd solution in benzene solution, c) 0.1M furfurylamine solution in benzene solution, and d) 0.1M phenylacetic acid solution in benzene . Results from this experiment will help understand the effect of starting materials on the solubility of UCExp251-1C in a Ugi reaction.

Result


Spreadsheet ONSCExp144-i


Discussion

It appears that the solubility of the Ugi product 176C is doubled to 0.06M in the presence of 0.1M phenylacetic acid in benzene. It remained unaltered (0.03M) in 0.1M phenanthrene-9-carboxaldehyde in benzene solution and in 0.1 furfurylamine in benzene solutions.
[That is very interesting - also do the SAMS on the added solute to confirm they are close to 0.1M JCB]-ok
Calculated SAMS concentrations for aldehyde, amine and acid in the solutions made, agree with the experimental concentrations (+/-0.03M). [good JCB]

To be done [compare the concentration of the Ugi product formed in the reaction mixture saturated with the Ugi product, using the supernatant HNMR from UCExp252-4A]
[it would probably be worth doing 0.2M and 0.3M phenylacetic acid as well to fully understand what might be happening during the course of the Ugi reaction JCB]
[Can you come up with an interaction between the Ugi product and phenylacetic acid that might explain this behavior? JCB]
I think there are two possible ways in which phenylacetic interacts with the Ugi product in benzene.
a) protonate the amide oxygens (one or both), making them positively charged (as in amide hydrolysis), but this would result in an ionic species- which I believe should decrease its solubility in benzene, but obviously a contrasting effect is observed.
Also an ion pair formation may not be very like because benzene being relatively non polar would not support ion pair formation. Another type of interaction could be a simple hydrogen bonding between the acid and the Ugi product.
b) the other possible interaction that I can think of is the increased pi-pi stacking (non-covalent interactions) hydrogen bonded phenylacetic acid with the Ugi product and the solvent benzene or . [have to look-up for references to support the point]. This type of interaction could possibly increase the Ugi product's solubility in the solution.

Conclusion

Solubility of the Ugi product 176C doubled in 0.1M phenylacetic acid solution in benzene compared to benzene . It however remained unchanged in 0.1M phenanthrene-9-carboxaldehyde and 0.1M furfurylamine solutions in the solvent.

Log

2009-11-06
15:00 Turned on Lauda heating / cooling device and set the water/glycol bath to 40C
15:15 Weighed out 14mg phenylacetic acid in a 1ml volumetric flask. Put a small amount of benzene to dissolve, then filled benzene up to the mark of 1ml volumetric flask. The concentration was 0.1M.
15:30 Put this solution in to one dram vial. Labeled C.
16:00 Weighed out 10 mg of phenanthrene-9-carboxaldehyde in another one dram vial. Put 476.8 uL of benzene into the vial. The concentration was 0.1M. Labeled the vial A.
17:00 Took 8.83 uL of furfurylamine in a mL volumetric flask. Filled to mark with benzene. the concentration is 0.1M. Labeled B.
17:10 Pipetted out benzene (200uL) in to two clean half dram vials, added a small amount of UCExp251-1C and vortexed them for ~15s. Made sure some of the solute was left undissolved. These solution are now labeled ONSCExp144-1 and ONSCExp144-2
17:15 Pipetted out 200uL of solution A (0.1M phenanthrene-9-carboxaldehyde solution in benzene) in to two clean half dram vials, added a small amount of UCExp251-1C and vortexed them for ~15s. Made sure some of the solute was left undissolved. These solution are now labeled ONSCExp144-3 and ONSCExp144-4
17:20 Pipetted out 200uL of solution B (0.1M furfurylamine solution in benzene) in to two clean half dram vials, added a small amount of UCExp251-1C and vortexed them for ~15s. Made sure some of the solute was left undissolved. These solution are now labeled ONSCExp144-5 and ONSCExp144-6
17:20 Pipetted out 200uL of solution A (0.1M phenylacetic acid solution in benzene) in to two clean half dram vials, added a small amount of UCExp251-1C and vortexed them for ~15s. Made sure some of the solute was left undissolved. These solution are now labeled ONSCExp144-7 and ONSCExp144-8.
17:30 Parafilmed all 8 vials.
17:50 Placed the vials in the lauda heating/cooling bath. The temperature in the bath was 40C
18:25 Adjusted the temperature in the bath to 25C.
19:00 The temperature in the bath reached 25C
2009-11-07
10:40 Turned off the water/glycol bath and removed the vials. All vials contained some of undissolved solid, indicating that these solutions are saturated.
10:50 Centrifuged the vials containing the saturated solutions and carefully pipetted out approximately 100uL of the supernatant from each vial in to clean and dry one dram vials containing 700uL DMSO-d6 and labeled accordingly.
Centrifuged solution
DMSO-d6+ ~100uL supernatnant
new label
ONSCExp144-1
ONSCExp144-1A
ONSCExp144-2
ONSCExp144-2A
ONSCExp144-3
ONSCExp144-3A
ONSCExp144-4
ONSCExp144-4A
ONSCExp144-5
ONSCExp144-5A
ONSCExp144-6
ONSCExp144-6A
ONSCExp144-7
ONSCExp144-7A
ONSCExp144-8
ONSCExp144-8A
12:05 Obtained HNMR of the solutions, ONSCExp144-1A, ONSCExp144-2A, ONSCExp144-3A, ONSCExp144-4A, ONSCExp144-5A, ONSCExp144-6A, ONSCExp144-7A and ONSCExp144-8A