brite_lites
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My teacher didnt know
Sorry for posting such a stupid question but my chemistry teacher's not the brightest of sparks so she didnt know the answer: Is dimethyl
sulphoxide the same as dimethyl sulphate?
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chloric1
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no
The sulfoxide has only one oxygen and two methyl groups attached to a sulfur atom. Dimethyl sulfate is actually an ester of sulfuric acid, having
sulfur in its highest oxidation states.
Next time, just nod and smile when your teacher lectures and make sure to to have backup sources of information handy. There are numerous chem
dictionaries that could answer basic questions like this. Some of the compact paperback versions are as cheap as $14.99!! So, be assertive and buy a
couple references for your home use!
Fellow molecular manipulator
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brite_lites
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Ok thanks very much but I live in Ireland so nothing is cheap. Are both methylating agents or is it just the sulphate? Also is dimethyl sulphoxide
difficult to obtain? Where can I buy it mailorder?
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BromicAcid
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I do not believe there are any feasibly obtainable conditions under which DMSO can be used to a noticeable extent as a methylating agent. Also, DMSO
is easy to obtain here in the states, a number of companies carry it, one use being for horses, I know unitednuclear.com carries it but I don't
know if they ship over seas, just check around. If you want some other information on DMSO just ask.
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mick
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DMS, Dimethyl sulphate is a high boiling liquid with no smell, but once in side your body I think it might be able to methylate DNA and cause a lot of
problems.
DMSO, Dimethyl sulphoxide, is used to disolve drugs and is readily adsorded through the skin.
mick
DMSO + strong base might give you a methalating reagent.
[Edited on 12-10-2004 by mick]
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svm
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"DMS" usually refers to dimethylsulfide (where the sulfur doesn't have any oygens on it). it's a foul smelling liquid with a bp
of 38 degrees C.
dimethyl sulfate is indeed a good methylating agent, but it's slower than some others like methyl iodide.
as bromic said, I don't think there is a way to turn DMSO into a methylating agent. if you use a strong base, like mick said, it is a useful,
selective base for making enolates, etc., but it never delivers a methyl group.
if you treat DMSO with methyl iodide you can make a new compound where there are three methyl groups on the sulfoxide. that reagent can be treated
with a strong base and then used to turn ketones into epoxides (by delivery of one of the three methyl groups). this is the opposite of most
methylating reagents though, since it is nucleophilic not electrophilic.
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JohnWW
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Re possible uses of DMSO:
In my inorganic chemistry laboratory class, many years ago now, I was given the preparation of a (CH3)2S=O (DMSO) complex of Fe(III) to do, using
acid FeCl3 solution. As I remember, the product, obtained as a yellow powder, contained two different types of Fe(III) atom, and I think the formula
was either [Fe((CH3)2SO)4Cl2]+[FeCl4]- or [Fe((CH3)2SO)4]+++([FeCl4]-)3. The two types of Fe atom in the compound makes it an interesting subject for
a Mossbauer spectroscopy study, as well as for UV spectroscopy. I am not sure whether the coordinate bonding to the Fe was through the O or S atoms,
although Fe(III) bonds more strongly to S.
DMSO is used as an "alternative" topical treatment for pain, including arthritic joints, although to be safe for the purpose it would
probably have to be diluted.
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Marvin
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DMSO isnt diluted for medical use, its more of a method of getting drugs inside the body.
In essence its topical use is based on it being a solvent thats extremely good at going through the skin. You take the drug in question, dissolve it
in the neet DMSO and rub it on using the right type of gloves to avoid getting a dose of it yourself.
I'm told reliably that if you dip your little finger in DMSO and count to 7 you can *taste* it.
While its not toxic itself the rapid through skin transport can make solutions very toxic indeed, for example using NaF as a base in DMSO provides a
very rapid method for the NaF to enter the body if it touches skin. This means extra care needs to be taken using what is essentially a non toxic
solvent.
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Theoretic
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Once dimethyl sulfate is inside your body, you wouldn't worry about your DNA methylating and the like. You'd be hollering your head off,
 as DMSA quickly hydrolyses to sulfuric acid and methanol UNDER your skin, which
doesn't feel nice.
DMSO makes NaF behave like a BASE?
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neutrino
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DMSO make many things act like stronger bases.
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svm
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right. the oxygen of DMSO is very good at solvating cations, but the positively charged sulfur is shielded so it can't solvate anions very well.
the effect is that you have more of a "naked" anion, and thus a stronger base/nucleophile.
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Marvin
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NaF is a very strong base, the problem is water is also an acid so you are in effect limited to the strength of the conjugate base. In DMSO this
doesnt happen and F- can do more impressive things.
Its a little like adding sodium amide to water and expecting to see a really strong base. It reacts with the water, and your stuck with the conjugate
base sodium hydroxide which is no better than adding sodium hydroxide in the first place. A solvent that cant happen in, say liquid ammonia alows the
amide ion to do its stuff like rip chlorine atoms of aromatic rings...
svm's point also sounds valid but was previously unknown to me.
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