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https://pubs.acs.org/doi/10.1021/acs.jmedchem.8b01523 
Granberg KL, J. Med Chem. 2019, 62, 3, 1385-1406. 

One thing that attracted me to this method is that the ratio of the methyl sulfonamide to base to the chlorophosphate is 1:2:1; in other words, there is not the approximate twofold of excess of the methyl sulfonamide over the phosphorylating agent that I found in most other protocols.  As to what is different, my speculation is that the steric bulk of this base prevents it from removing a proton from the product, which is more acidic than the starting material.

Or maybe the product becomes a lithio enol? I know that ethyl acetate is best lithiated by LiHMDS it gives better yields, better than LDA. Its interesting. I dont know if steric bulk stops deprotonation, maybe it does
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As far as I know, Valence shell electrons don't shield other valence shell electrons from the proton in the nucleus, and outer shell electrons don't shield inner shell electrons.
This is incorrect. Valence shell electrons do shield other valence shell electrons; the effect is not as strong as the shielding effect by inner shell electrons, but it is not negligible. An outer shell electron may even spend some of its time closer to the nucleus than an inner shell electron, meaning a valence shell electron may exhibit a small shielding effect on an inner shell electron. Depending on your level of study, you may want to review structural models of the atom to have a better understanding of why this is the case.

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If effective nuclear charge is net pull inwards by all the protons in the nucleus on outer electrons, why does removing a outer electron increase the net pull by the protons on outer electrons inwards? As far as I know, Valence shell electrons don't shield other valence shell electrons from the proton in the nucleus, and outer shell electrons don't shield inner shell electrons.

I'm learning about cations smaller than their neutral atoms.

If F_electrostatic=kq_1q_2/r^2. Let q_1 be charge of nucleus' proton(s) which is constant if you make a neutral atom a cation. AFAIK: If q_2 is negative and becomes smaller because you pulled out an electron to form some cation, then you're decreasing attractive force inwards towards the nucleus, which means that quite absurdly you're decreasing effective nuclear charge contrary to what my source says.
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Yes, it is difficult.  It's best to read all the related paragraphs, because sometimes there's a bit of an out.  But that value is not too strange for either the EP or the USP.  It can make titration quite interesting.  There are some tricks played.  Some of the techs would make sure their weights were always as close to identical as possible ( before dissolving a reference standard, if done by weight). Then the titration volumes should be nearly the same, as well.  And trying to get by with the minimum amount of indicator and using white surfaces, as well as good volume reading, helps a lot.  The automated equipment was only helpful if doing many identical standardizations.  It was usually more of a pain than it was worth to us.  Good luck.
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https://pubs.acs.org/doi/10.1021/acs.jmedchem.8b01523 
Granberg KL, J. Med Chem. 2019, 62, 3, 1385-1406. 

One thing that attracted me to this method is that the ratio of the methyl sulfonamide to base to the chlorophosphate is 1:2:1; in other words, there is not the approximate twofold of excess of the methyl sulfonamide over the phosphorylating agent that I found in most other protocols.  As to what is different, my speculation is that the steric bulk of this base prevents it from removing a proton from the product, which is more acidic than the starting material.
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Dear.. as indicated in paragraph 4.2.2 of the European Pharmacopoeia, it is necessary that the replications relating to the correction factor respect a max rsd of 0.2 it is really difficult to obtain this repeatability. especially for low concentrations.. do you have any ideas?

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Great! Maybe there is a cool explanation why the LiHMDS is better to use
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A few months ago we used lithium hexamethyldisilazane, LiHMDS, as the base to remove a proton from a methyl sulfonamide.  We used diethylchlorophosphate as the phosphorylating agent.  The reaction gave the desired product, and I am inclined to use it in preference to nBuLi.
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Organic Chemistry Forum / Re: .
« Last post by Borek on May 15, 2024, 02:50:06 PM »
Please consult the forum rules - you agreed to them when registering, but obviously you have never read them.

Editing your post just because you don't like the answer is against the rules as well.

Topic locked.
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Organic Chemistry Forum / Re: Bromination
« Last post by rolnor on May 15, 2024, 02:09:49 PM »
That's true, thanx. It's possible no catalyst is required
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