Monoamine
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Preparation of chlorosulfonic acid derived protecting groups
Hi All, I'm currently trying to make some sulfonic acid protecting groups for some upcoming projects.
For the most famous such protecting group, 4-Toluenesulfonyl chloride, the only way I saw how to make it is by using sulphurily chloride (SO2Cl2),
which can be made from SO2 and Cl2 (or S2Cl2 can be used together with SOS to make the compound.
My issue is that I don't have a very efficient ways to generate SO2 (in the quantities that re needed for a suable amount.
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clearly_not_atara
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I'm not aware of any way to make TsCl from SO2Cl2, either. Friedel-Crafts conditions will give mostly sulfone because TsCl is more electrophilic than
SO2Cl2. TsCl is conventionally prepared using chlorosulfonic acid together with BnH. Chlorosulfonic acid can be prepared using oleum, but this is not
easy.
Birch reduction of sulfones gives the sulfinates. This can be used to obtain mesyl chloride from methylsulfonylmethane:
Me2SO2 + Li(NH3)6 >> MeSO2Li + CH4
MeSO2Li + Cl2 >> MeSO2Cl + LiCl
[Edited on 04-20-1969 by clearly_not_atara]
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Fery
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Monoamine ask our forum member chemship1978 for chlorosulfonic acid, I've bought it from him some time ago. IIRC also woelen got it from some NL shop:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...
He is mentioning es-drei.de but they seem do not sell it anymore:
https://shop.es-drei.de/saeuren/
If you need tosyl chloride, I've bought it from here: https://chemcraft.su/product/24783
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woelen
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Unfortunately, both of my sources of chlorosulfonic acid stopped selling it. I can imagine that, because of its very corrosive properties. The stuff
reacts violently with water and contact with skin leads to instant destruction and chemical burns. Stuff to be treated with respect. Once neutralized
and diluted by water, however, the resulting liquid is benign and can be flushed down the drain without adverse environmental impact.
Making it from SO2Cl2 is very hard. H2SO4 and SO2Cl2 do not react with each other to make SO2Cl(OH).
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Boffis
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I have a real hard-copy book on naphthalene chemistry. Throughout the book it describes the preparation of various naphthalene sulphonyl chloride and
while some are prepared directly, using chlorosulphonic acid in excess, the majority are prepared from the sodium salt of the sulphonic acid and a
chlorinating reagent such as phosphorus pentachloride. I am not at home at present and I have not been able to find a digital copy of this massively
useful book or I would scan some of the preps for you. But many of the preparations are covered by patents or technical references and it should be
possible to find a few representative procedures.
Sulphonyl chlorides can also be prepared by the oxidation of aromatic disulphides with nitric acid and chlorine, this procedure is covered in Vogel
under the preparation of orthanilic acid (2-aminobenzene-sulphonic acid).
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