11-22-2015, 01:32 AM
Cuddly Wrote:TLC and 1H-NMR spectra
Don't forget MS. Probably ESI with ammonium hydroxide 0,1% .
TLC --> ESI-MS --> 1H-NMR
Motivate me, please!
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11-22-2015, 01:32 AM
Cuddly Wrote:TLC and 1H-NMR spectra Don't forget MS. Probably ESI with ammonium hydroxide 0,1% . TLC --> ESI-MS --> 1H-NMR
11-22-2015, 01:44 AM
Insertnamehere Wrote:Don't forget MS. Probably ESI with ammonium hydroxide 0,1% . Ugh, I never liked MS. Luckily for me, that's not part of tge assignment, although fitting. What do you mean by that bottomline though? Is that the standard order of operation to identify an unknown substance or something? I'm not identifying, I know what I'm looking at, I just need to assign peaks and couplingconstants to the hydrogen atoms.
11-22-2015, 01:45 AM
http://www.ncbi.nlm.nih.gov/pmc/articles...o=0.406504
Would you be able to use this thread to get some insight on your paper? Maybe [MENTION=23097]Insertnamehere[/MENTION] can point you in the right direction. . ?Ask him?
11-22-2015, 01:52 AM
I really hate using the Tapatalk aplication sometimes..
It doesn't always load the posts in order .. Apologies. . You guys were already at it..
11-22-2015, 01:56 AM
Cuddly Wrote:Ugh, I never liked MS. Luckily for me, that's not part of tge assignment, although fitting. Do you? The standard prodecure after synthesis involves purification and then identification as the non-negotiable step to check whether the synthesis was successful. 1H-NMR is expensive and requires a rather large amount of purified sample so if the reaction doesn't past the MS checkpoint, you wouldn't consider to go further. Of course, that is real life, I dunno how it is structured in your assignment, cause perhaps they already gave you the MW. You could also consider HPLC over TLC, HPLC with something so hydrophilic would need a silica column. HPLC is much more prevalent and has better resolutions. In any case, checking all the protons in the RMN spectra shouldn't be all that hard. The actual synthesis interests me. As I understand, a glucosyl is a free radical intermediate, and the initial acetyl groups are certainly protecting groups to ensure only the hemiacetal group is dehydrogenated, how is it dehydrogenated, I wouldn't know yet. Afterwards, under pH 2 or over pH 9, the acetyl groups are removed. I suppose acid and heat are more frequently used.
11-22-2015, 04:20 AM
meditate, forsake that man and move on
11-22-2015, 11:07 AM
Insertnamehere Wrote:Do you? The synthesis starts with the 1234 6 protected glucose. So the reaction must be regioselective to the anomeric carbon atom. In case you're wondering why the glycosyl bromide sits in alpha position, it is because this is thermodynamically favourable. This glucosyl bromide is the used in two seperate reactions to form either a thioglucoside or 3-Phenylpropyl glycoside. The latter was purified with VLC and rotovap. The former by rotovap and recrystalization.
11-22-2015, 03:53 PM
Cuddly Wrote:The synthesis starts with the 1234 6 protected glucose. So the reaction must be regioselective to the anomeric carbon atom. Hydrogen Bromide eh? Adition/Elimination then. Nice. So, probably a basic media to remove the protecting acetyl groups. Alrighty then, so what are you waitin g for, go go go, put this all in writing |
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