86B

62E

104C

64C

108C

109C
150D

171K

173B

173G

176


Objective

To estimate the solubility of eleven Ugi products in methanol by proton magnetic spectroscopy.

Procedure

Saturated solution of eleven Ugi products was prepared in methanol by adding the solute to a small amount of methanol (200-300uL) in one dram vials. The solutions were vortexed for 10min and left to equlibrate over night. The supernatants were then separated from the solutions after centrifuging. The saturated supernatants were then dissolved in a CDCl3 (700uL) and an internal standard 1,2-dichloroethane was added to then before HNMR spectra was obtained for each.

Results

HNMR
Solute
Solvent
Int. Std
SAMS Solubility (M)
HNMR
86B
CH3OH
DCE
0.17
HNMR
62E
CH3OH
DCE
0.13
HNMR
104C
CH3OH
DCE
0.29
HNMR
64C
CH3OH
DCE
0.03
HNMR
108C
CH3OH
DCE
0.36
HNMR
109C
CH3OH
DCE
0.15
HNMR
150D
CH3OH
DCE
0.07
HNMR
171K
CH3OH
DCE
0.02
HNMR
173B
CH3OH
DCE
0.08
HNMR
173G
CH3OH
DCE
0.18
HNMR
176
CH3OH
DCE
0.08
SpreadsheetONSC-EXP065C



86B -- 0.1701M


62E -- 0.1263M


104C -- 0.2929M


64C -- 0.034M

108C -- 0.3577M


109C -- 0.1501M


150D -- 0.0742M


171K -- 0.0171M

173B -- 0.081M


173G -- 0.1828M


176 -- 0.0834M


Discussion

The t-tbutyl group was used to calculate the solubility, using the SAMS spreadsheet. This calculation does not require an internal standard and assumes that the volumes of the two components (solute and solvent) are additive, the volume of the solid solute is calculated by using its predicted density available on ChemSpider.
The t-butyl group (where ever available) was used as the sample peak to integrate against solvent peak. The t-butyl methyl protons are assumed to relax much faster than than the ones on the rings or double bonds, therefore these protons may be more reliable than others.


Conclusion

Solubility of eleven Ugi products in methanol has been successfully determined using SAMS.

Log

2009-02-26

22:40 Saturated solutions of eleven Ugi products, 86B, 62E, 104C, 64C, 108C, 109C, 150D, 171K, 173B, 173G and 176 was prepared in methanol by vortexing methanol (approximately 250-350uL) and each Ugi product in a one dram vial for 10min.
23:20 The solutions were left to equilibrate overnight at room temperature (28C)

2009-02-27

14:00 The solutions were centrifuged and the supernatants were poured out in to different vials and labeled accordingly.
17:00 To clean NMR tubes CDCl3 (700uL) was added followed by 1,2-dichloroethane (10uL) and supernatants (100uL). The solutions in the NMR tubes was mixed thoroughly.
20:40 Obtained HNRMs of the solutions on a 500MHz varian instrument.