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Solubility book (3rd Edn)
To estimate the solubility of eleven Ugi products in methanol by proton magnetic spectroscopy.
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.
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
The t-tbutyl group was used to calculate the solubility, using the
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
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.
Solubility of eleven Ugi products in methanol has been successfully determined using
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)
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.
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