Objective


To study the effect of imminium (of phenanthrene-9-carboxaldehyde+ furfurylamine+phenylacetic acid) on the solubility of the Ugi product UCExp176C in benzene.

Procedure

A 0.3M solution per component of phenanthrene-9-carboxaldehyde, furfurylamine and phenylacetic acid was made-up in benzene in a 5mL volumetric flask. Using this as a stock solution serial dilution was performed as shown in the table below to obtain dilute solutions 0.3M, 0.15M, 0.075M, 0.0375M, 0.018M, 0.009M, 0.0046M, 0.002M, 0.001M, 0.0005Ma and 0M.
To the dilute solution in benzene Ugi product UCExp176C was added until no more of the solute dissolve upon vortexing. These solutions were placed in a temperature controlled bath at 40C for 12h. Then the temperature was reduced to 25C, with the samples left to equlibrate for another 2h.
Supernatants from each sample vial was separated and HNMRs were obtained. Using SAMS methodology solubility of the Ugi product was obtained.

Results

Spreadsheet ONSCExp156-i
Spreadsheet ONSCExp156-ii

Discussion



ONSCExp156plot-i.jpg
Figure 1: Plot of the Ugi product 176C solubility in benzene as a function of imminium concentration.

There appears a linear relation between solubility of the Ugi product and the imminium concentration from 0.007M and higher. The equation of this linear line is y = 0.1647x + 0.0472 with an R^2 = 0.9985. Corresponding Imminium concentration for Ugi product UC176C at 0.23M* was calculated at 0.8M

Note : * Represents the solubility of the Ugi product UC176C in its 4-component reaction mixture.

Based on the results from Exp157, it is obvious that the effect of the imminium is mostly because of phenylacetic acid. Therefore in a 4-component Ugi reaction, product yield of UC176C seems to be primarily dependent on the concentration of unreacted phenylacetic acid in the solution and its solubility in pure solvent, benzene and to a lesser extent on the concentration of imminium ion.

Conclusion


Solubility of the Ugi product UC176C increases linearly with imminium concentration. The imminium effect is mostly because of the acid in it.

Log

2009-12-21
10:20 Weighed out furfurylamine (145.7mg, 0.15mmol), phenanthrene-9-carboxaldehyde (309.4mg, 0.15mmol) and phenylacetic acid (204.3mg, 0.15mmol) in a 5mL volumetric flask on a top loading balance with a 0.1mg reading capability.
10:50 Added a small volume of benzene to dissolve the solid in the 5mL volumetric flask, then made-up to the mark by adding a few drops of solvent. Vortexed the solution to mix well and obtained a 0.3M per component solution. This is labeled ONSCExp156-1A
11:10 Transferred 100uL of the ONSCExp156-1A in to a clean NMR tube with ~0.5mL DMSO-d6, mixed well and obtained an HNMR, ONSCExp156-1A and ONSCExp156-1A-bc.
11:45 Concentration of each component was confirmed to be 0.3M in the solution.
13:00 Performed serial dilution of ONSCExp156-1A as shown in the table below (Table -156-i). All calculations is represented in the Spreadsheet ONSCExp156-i
Table 156-i
Solution
ID

Stock
Conc (M)

Stock
vol (mL)

Final
Vol (mL)

Final
Conc
(M)
1A
0.3
1
1
0.3
2A
0.3
1
2
0.15
3A
0.15
1
2
0.075
4A
0.075
1
2
0.037
5A
0.0375
1
2
0.018
6A
0.0187
1
2
0.009
7A
0.0093
1
2
0.005
8A
0.0046
1
2
0.002
9A
0.0023
1
2
0.001
10A
0.0011
1
2
0.0005
11A (blank)
0
0
0
0
12A (blank)
0
0
0
0
15:00 Samples 11A and 12A are blanks.
15:30 In to 12 clean half dram vial labeled ONSCExp156-2A through ONSCExp156-10A, containing a small amount of UCExp176C, approximately 400uL of the corresponding (#A series) solution was added. The vials were vortexed and made sure some of the solute still remained at the bottom of the vials.
16:20 Switched on the heater on the water/glycol bath and set it to 40C. Parafilmed the vials.
16:50 Temperature had reached 40C. Placed the vials in the water/glycol bath at 40C.
2009-12-21
11:45 Changed the setting of the water/glycol bath to 25C.
18:45 Removed the vials from the bath.
19:20 In to twelve clean/dry NMR tubes, pipetted out DMSO-d6 (~200uL) and labeled the tubes ONSCExp156-1A-1 and ONSCExp156-2A, ONSCExp156-3A, ONSCExp156-4A, ONSCExp156-5A, ONSCExp156-6A, ONSCExp156-7A, ONSCExp156-8A, ONSCExp156-9A, ONSCExp156-10A, ONSCExp156-11A, ONSCExp156-12A.
19:55 Transferred approximately 200uL of the supernatant from each vial in to the corresponding NMR tubes.
22:30 Obtained HNMRs of ONSCExp156-1A-1 through ONSCExp156-12A