Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Pregnenolone sulfate synthesis
loststar0
Harmless
*




Posts: 8
Registered: 7-7-2015
Member Is Offline

Mood: No Mood

[*] posted on 7-7-2015 at 07:16
Pregnenolone sulfate synthesis


Can anyone synthesize pregnenolone sulfate from pregnenolone or get it for under $30 / 150 mg.

[Edited on 7-7-2015 by loststar0]
View user's profile View All Posts By User
Praxichys
International Hazard
*****




Posts: 1053
Registered: 31-7-2013
Location: Detroit, Michigan, USA
Member Is Offline

Mood: Coprecipitated

[*] posted on 7-7-2015 at 09:05


Seems pretty straightforward.

Methyl alcohol is converted to dimethyl sulfate using cold concentrated sulfuric acid. Dimethyl sulfate undergoes partial hydrolosis to methyl bisulfate.

2x + H2SO4 --> + H2O --> x2

Similarly (hypothetically) with pregnenolone to pregnenolone (bi)sulfate:

-- same process -->

I think the main competing reaction may be acid addition of water across that unsaturated bond. The product, being fairly acidic, could be isolated with a quick a/b extraction. The differences in pKa between the reactant and product probably make it a good candidate for column separation, if TLC shows it is necessary. Perhaps adsorbtion/desorbtion on a cation exchange column as the sodium salt?

Might be worth a try if the offer is $200/gram. Although Sigma sells the sodium salt for $600/gram...




View user's profile Visit user's homepage View All Posts By User
MrHomeScientist
International Hazard
*****




Posts: 1803
Registered: 24-10-2010
Location: Flerovium
Member Is Offline

Mood: No Mood

[*] posted on 7-7-2015 at 10:38


Why is it that nearly every organic chemistry reaction uses sulfuric acid as a catalyst (and requires reflux for days)? What's so special about it? Why not other acids? Why are acids required at all? Forgive me for my ignorance, but I never took organic chemistry in school nor do I practice it at the hobby level.


Awaiting the chorus of angry exceptions to my limited (and biased) observations. If you didn't get the hint, I prefer inorganic :P
View user's profile Visit user's homepage View All Posts By User
SimpleChemist-238
Hazard to Others
***




Posts: 147
Registered: 28-9-2014
Member Is Offline

Mood: Chlorine Trifloride Flame Thrower

[*] posted on 7-7-2015 at 11:08


Sulfuric acid is quite useful, its used as a acid catalyst in a voluminous amount of reactions because of its properties. Its a strong acid and also can remove water from many reactions. For example in the synthesis of methyl benzoate were water can drive the reaction back yielding the reactants. For example nitric acid is not used because it often acts like a base, this is why sulfuric acid reacts with it to form the nitronium ion responsible for nitration.



We are chemists , we bring light to the darkness. Knowledge to ignorant, excitement to the depressed and unknowing. we bring crops to broken fields and water to the desert. Where there is fear we bring curiosity.

View user's profile View All Posts By User
gdflp
Super Moderator
*******




Posts: 1320
Registered: 14-2-2014
Location: NY, USA
Member Is Offline

Mood: Staring at code

[*] posted on 7-7-2015 at 11:23


Quote: Originally posted by SimpleChemist-238  
Sulfuric acid is quite useful, its used as a acid catalyst in a voluminous amount of reactions because of its properties. Its a strong acid and also can remove water from many reactions. For example in the synthesis of methyl benzoate were water can drive the reaction back yielding the reactants. For example nitric acid is not used because it often acts like a base, this is why sulfuric acid reacts with it to form the nitronium ion responsible for nitration.

Nitric acid very rarely acts as a base, the nitration reaction is fairly unique in this aspect. This is not the reason why nitric acid is nearly never used as an acid catalyst in organic chemistry, it's due to it's highly oxidizing properties, especially at high temperature. Sulfuric acid is also used because of it's low volatility, as well as it's strength, allowing it to protonate, not necessarily fully but enough for a reaction to proceed, many common organic compounds such as alcohols, ketones, aldehydes, and esters.

Many organic reactions involve refluxing for several reasons. For one, it allows the temperature to be precisely controlled, determined by the choice of solvent. The other main reason is that while many simple inorganic reactions are driven by the concentration of ions(simple metathesis reactions are nearly instantaneous), organic reactions can have a very low reaction rate, increasing the temperature simply allows the reaction to proceed at an appreciable rate and overcomes the significant activation energy required by most organic reactions.




View user's profile View All Posts By User
smaerd
International Hazard
*****




Posts: 1262
Registered: 23-1-2010
Member Is Offline

Mood: hmm...

[*] posted on 7-7-2015 at 11:27


Interesting Praxichys

I was thinking along the lines of chlorosulfonic acid and a mild base. I guess the enolate could be a problem.

So maybe protect the ketone as a ketal, then chlorosulfonic acid + base, weak acid hydrolysis.




View user's profile View All Posts By User
Praxichys
International Hazard
*****




Posts: 1053
Registered: 31-7-2013
Location: Detroit, Michigan, USA
Member Is Offline

Mood: Coprecipitated

[*] posted on 7-7-2015 at 11:41


It's terribly convenient.

It's a high-boiling, diprotic, strong, slightly-oxidizing, dehydrating acid that forms both soluble and insoluble salts with alkali and alkaline earth metals.

Because of its high boiling point, it can be used to isolate a huge number of organic and inorganic acids from their salts through distillation. It dehydrates many organic compounds, forming acid anhydrides and ethers. It can add hydroxyls to alkenes and replace halides with unsaturated bonds. It can strip hydroxyls to alkenes at high temperatures or form sulfate esters at low temperatures, making great alkylating agents in the process. As a strong desiccant it has many uses in acid-catalyzed chemistry like esterification. Where lesser acids would boil away during reflux, a Fischer esterification goes smoothly with H2SO4. Various organic compounds may be forcibly dehydrated to useful products, like formic acid to make carbon monoxide. As a strong acid, it forces equillibria toward sulfate salts, freeing many organic acids with lesser pKa for liquid/liquid extraction, or for recharging ion exchange columns. Its high density makes it suitable for drying many organic phases. Sulfonated aromatic compounds gain solubility and resistance to oxidation, like in a classic picric acid synthesis. Then, when no longer necessary, sulfate can be precipitated as its calcium or barium salt, leaving an inert product ready for disposal and a nice, clean solution containing your target. Many amine sulfates are solids and easy to handle - conversely, many amine hydrochlorides are volatile liquids. The acid can be concentrated simply by heating it, allowing its easy reuse.

Sulfonic acids are ubiquitous in azo dyes, which provide color to most of the things one comes in contact with on a daily basis. Most plastics involve sulfuric acid somewhere in the process of making them, especially nylon and rayon. Long chain organic sulfonic acids are great surfacants in widespread use, all mode from sulfuric acid. It also has countless applications in batteries, fertilizer, explosives, pesticides and herbicides, electroplating, and metal refining and surface treatment.

Yes, sulfuric acid... I'd bathe in the stuff if I could. I can easily name it as the single most useful (and probably most used) reagent I have, apart from water.

:D




View user's profile Visit user's homepage View All Posts By User
MrHomeScientist
International Hazard
*****




Posts: 1803
Registered: 24-10-2010
Location: Flerovium
Member Is Offline

Mood: No Mood

[*] posted on 7-7-2015 at 12:20


Great answers! I appreciate the lesson.
View user's profile Visit user's homepage View All Posts By User

  Go To Top