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UC on ChemSpider
Alicia's Masters Thesis
Open Web Drug Dev.
To Do List
Ugi NMR Analysis
To isolate the
after a prolonged treatment of
with 50% trifluoroacetic acid in CDCl3 inorder to answer the
rewrite to standard of experimental format - all full sentences and actual times and amounts from log
Dissolved 47.5 mg (0.1 mmol) of the Ugi product 86B from
in 500 uL CDCl3. Then 500 uL of trifluoroacetic acid was added to the above solution in the NMR tube (50% solution in CDCl3) The reaction was monitored by NMR. After a complete conversion the solution was poured into a centrifuge tube and neutralized using 10% NaOH solution. The organic component was extracted from the solution using dichloromethane and dried with anhy. MgSO4. The product was subjected to NMR and MS analyses.
Characterization of 97B
2-[(aminoacetyl)amino]-N-tert-butyl-2-phenylacetamide: Brown oil; 1H NMR (
ppm, CDCl3) 1.28 (s, 9H), 1.85 (sb, 2H), 3.35 (sb, 2H, 5.45 (d, 1H,
6.8 Hz), 5.84 (s, 1H), 7.26-7.42 (m, 5H), 8.27 (d, 1H
6.8 Hz); 13C NMR (
ppm, CDCl3) (
put numbers in sequence and double check them - some are obviously wrong
) 28.5, 44.7, 51.7, 56.7,1 27.2, 128.1, 12.9, 138.5, 169, 172.2; FAB MS 264.78 (nominal), 267.1703 (exact mass). Yield- 100%? Quantitative conversion.
(C25H35N3O5, Mol. Wt.: 457.56)
All protonated carbons
Overlay of C NMR and All protonated carbons
t = 05min
t = 09min
t = 13min
t = 33min
t = 43min
t = 50min
t = 01h 00min
t = 01h 02min
t = 02h 05min
t = 02h 07min
t = 18h 01min
t = 45h 29min
t = 66h 01min
t = 6 days
(Extract of the basified 097A in CDCl3)
Kinetcs spreadsheet- UCExp097-1
Tentative H NMR assignments of 97B
Fig - UCExp09-i : Kinetics of 1,6-methylfurfuryl elimination
Kinetics of the 1,6-methyl furfuryl elimination from the Ugi product 086B in 50% TFA in CDCl3, was determined to be first order with a rate constant
k= 0.9x10-3 min-1
This is similar to the kinetics of 1,6-elimination observed previously;
50% TFA/ CDCl3
k = 1.2x10
50% TFA/ CDCl3
k = 0.9x10
From the NMRs it can be conclusively said that, after an initial boc deprotection, the ugi product undergoes a loss of methyl furfuryl group which has been recorded several time in analogous ugi products (with methyl furfuryl group) under similar conditions as in
This has also been reported in the
18:00 Weighed the ugi product (86B) (47.5 mg, 0.1 mmol) in an NMR tube and dissolved it in CDCl3 (500 uL)
18:49 Obtained H NMR of the ugi product 86B in CDCl.
19:02 Added TFA (500 uL) to the NMR tube, this is
19:07 Obtained H NMR of 97A. (t = 05min)
19:11 Obtained H NMR of 97A (t = 09min)
19:15 Obtained H NMR of 97A (t = 13min)
19:35 Obtained H NMR of 97A (t = 33min)
19:45 Obtained H NMR of 97A (t = 43min)
19:52 Obtained H NMR of 97A (t = 50min)
20:02 Obtained H NMR of 97A (t = 1h 00min)
20:04 Obtained H NMR of 97A (t = 1h 02min)
21:07 Obtained H NMR of 97A (t = 2h 05min)
21:09 Obtained H NMR of 97A (t = 2h 07min)
13:03 Obtained H NMR of 97A (t = 18h 01min)
16:31 Obtained H NMR of 97A (t = 45h 29min)
13:03 Obtained H NMR of 97A (t = 66h 01min)
17:41 Obtained H NMR Of 97A (t = 6days)
18:00 Poured the contents (97A) of the NMR tube into a centrifuge tube and basified the acidic (pH ~1) solution with 10% NaOH (2 mL) until the pH reached ~10. As the base was added to 97A, the centrifuge tube warmed up, and the deep brown color of the solution lost its intensity.
18:15 Added dichloromethane (3 mL) to the centrifuge tube, mixed the contents well by squirting with a pasteur pippet. The deep brown bottom layer settled, on top of which a clear aqueous layer incorporating a yellow precipitate (almost at interface of the organic and aqueous layers) appeared.
18:30 The bottom organic layer was pipetted out and the top aqueous layer was extracted once agian with methylene chloride (2 mL).
18:45 The organic layers were combined together and washed with distilled water (2 mL). The accumulated brown organic layer was dried with anhydrous MgSO4.
21:00 After letting sit in for about half an hour in MgSO4, dichloromethane containing brown liquid was set on a vacuum pump for evaporation.
21:35 After evaporating the solvent
(29mg) was obtained. [ Problem with the yield- because a 100% recovery cannot be more than 26.3mg, weight likely swollen by some solvent or other impurities]
19:06 Obtained H NMR of
by dissolving it in CDCl3 (1ml)
09:49 Obtained C NMR of
16:30 Obtained mass spectra (both low resolution and the exact mass)
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