Pregnenolone sulfate synthesis

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...

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

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.

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.