Author Topic: The Dimsyl ion and its uses in Organic synthesis. (Read 579 times)

Sedit · « **on:** November 22, 2009, 06:57:48 PM »

The Dimsyl ion is a very useful super base used in organic synthesis to affect a wide variety of reactions. It can be synthesized in good yeilds thru the addition of a strong base such as an alkali hydride(NaH, KH) or alkali amide(NaNH2). Newer Methods exist that facilitate the generation of the Dimsyl ion as well that include the electrolysis of a soluble alkali salt in DMSO[1]. As it stands this appears to be one of the safest and most readily avalible means of generating the deprotonated form of DMSO in that it does not require the use of dangerous hydrides and amides or the work of Elemental alkali metals.

One of the primary uses of the Dimsyl ion which causes me to write this thread is its ability to synthesis Allylbenzene in high yeilds thru the condensation of Styrene with Dimsyl ion and pyrolysis of the resulting intermediate.[2] Something I recently found intriguing is the fact that the addition of Alkali hydroxides is able to form the NaDMSO as well although the concentration is quite low[4]. As such I wounder if the above reaction will be able to proceed to the right by using up the Dimsyl ions as it forms keeping the concentration in the lower end ranges while still allowing the formation the sulfoxide in sufficient yeilds. There are good odds that since H₂O is a product here that the addition of a Molecular sieve may be needed to achieve the desired results. If experimentation proves this to be true then all one will need is to mix Styrene and DMSO at room temperature with KOH and allow a long stir at lower temperatures. This can then be followed by a steam distill to effect pyrolysis and liberate the resulting Allylbenzene. If higher temperatures where used to speed up the reaction you would be left with condensation products of Allylbenzene since the resulting sulfoxide degrades with relative ease.

As a methylating reagent:

One can see from this that the Dimsyl ion is effective in the methylation of Carbon-carbon Pi bonds in that it adds the sulfoxide followed with elimination thru refluxing the mixture following the initial reaction.

Quote

The dimsyl ion also adds to carbon-carbon double bonds, and if the mixture is heated for several hours, the initial adduct eliminates methanesulfenic acid. The overall result is methylation and with compounds such as quinoline or isoquinoline, yields are nearly quantitative [Russell, G. A.; Weiner, S. A., J. Org. Chem. 31, 248-251 (1966)] .

Source

This also seems like it could provide an effective means for the methylation of ?-nitro styrenes as long as the methylation proceeds at the ?-carbon as well. This means that for once substituted Benzaldahydes can possible be condensed with Nitromethane followed with this treatment of the Dimsyl ion to yeild the corrisponding Nitro compound which would be followed with a reduction to amphetamine.

To facilitate ester Cleavage and conversion to Methyl ketones
There is also another useful little tidbit of information a freind has kindly provided me with which shows one very important use of the Dimsyl ion in organic synthesis. What is interesting about this is its ability to add to Esters followed by a reduction with Al/Hg to yeild the given methyl Ketone[5]. One can envision with little effort the esterfication of Phenylacetic acid followed with treatment with NaDMSO and further reduction to yeild Phenylacetone. This eliminates the need for toxic lead but introduces the use of toxic Mercury so unless it is found that other methods of reduction can be used then I am not sure this is a viable option. However once the reaction mixture already contains Hg I can not help but wounder if the following reduction to an amine could be performed in a single pot reaction.

Conclusion:

As you can see from all of this the formation of the Dimsyl ion is critical in some very useful organic processes. There are quite a few means of synthesis but as it stands the electrochemical synthesis appears to be the most valid and as an added bonus the reference provided shows a means of synthesizing Grignard reagents without the hassles normaly associated with them. Much thanks goes out to our member shroomedalice for bringing this reaction to light for me sometime back and staying on top of it enough to find the electrochemical synthesis that cataylised this threads formation. I would very much like some feedback from our member base on the various uses and generation of the Dimsyl ions.

References:

[1]Versatile electrochemically based preparation of unusual Grignard reagents containing electrophilic substituents
Philippe Dauban, Robert H. Dodd
Tetrahedron Letters Volume 39, Issue 32, 6 August 1998, Pages 5739-5742

[2]The Addition of Dimethyl Sulfoxide Anion to Olefins and the Pyrolysis of Sulfoxides
Cheves Walling, Laszlo Bollyky
J. Org. Chem.,1964, 29 (9), pp 2699–2701

[3]Thermolysis of Alkyl Sulfoxides and Derivatives: A Comparison of Experiment and Theory
Jerry W. Cubbage, Yushen Guo, Ryan D. McCulla, and William S. Jenks
J. Org. Chem. 2001, 66 (26), pp 8722–8736

[4]Basicity of saturated solutions of alkali metal hydroxides in dimethylsulfoxide
B. A. Trofimov1, A. M. Vasil''tsov1 and S. V. Amosova1
Russian Chemical BulletinVolume 35, Number 4 / April, 1986, pg.682-686

[5]Swenton, J. S; Anderson, D. K; Jackson, D. K; Narasimhan, L (1981). "1,4-Dipole-metalated quinone strategy to (±)-4-demethoxydaunomycinone and (±)-daunomycinone. Annelation of benzocyclobutenedione monoketals with lithioquinone bisketals". J. Org. Chem. 46: 4825. doi:10.1021/jo00337a002.

Sedit · « **Reply #1 on:** November 22, 2009, 08:59:44 PM »

Im going to attach a Schematic of the Allylbenzene synthesis and propose a question for all those reading this.

The NaOH/DMSO solution only slightly generates the Dimsyl ion and this is more then likely due to the formation of an equalibrium with the formed H₂O which lays highly to the left of the reaction. However DMSO and H₂O have a large difference in boiling point and one should theoreticly be able to mix DMSO and NaOH and slowly distill the H2O to yeild almost quantative results of the NaDMSO ions. Think of it to a simular fashion to how Klute I believe it was generates Alkoxides over at Science madness.

Remove the water and what is left?
DMSO + NaOH <<---> H₂O + NaDMSO

You will push the reaction farther and farther to the right as the water is removed allowing more NaDMSO to stablize and more H₂O to form and be evaporated.

Sedit · « **Reply #2 on:** November 23, 2009, 12:28:18 AM »

To add to the thread I have decided to post a procedure I found on the net for the common preperation of the NaDMSO which uses Sodium Hydride for those that have access to that sort of thing.

Introduction
Dimsyl sodium is used for the alkylation of polysaccharide and sometimes oligosaccharides by the Hakomori procedure. It is a very strong base and it converts the polysaccharide to the polyanion. Treatment of DMSO with NaH gives dimsyl sodium, under the evolution of hydrogen gas. Because of its flammability NaH is kept in oil which must be washed away before the reaction with DMSO. The NaH-suspension should be grey, if it is white that is a sign of NaOH coming from moisture. Petroleum ether or hexane is used for this. The resulting solution of dimsyl sodium is 2M.

Reagents
•Sodium hydride in oil (50%)
•Petroleum ether
•DMSO pro analysi
•serum flasks 10 and 25 mL
•Needles 0.9 mm, or somewhat larger.

Procedure
1.Put the NaH/oil dispersion (1 g) in a 25 mL septum flask and seal it. Wash with petroleum ether/hexane (15 mL) by stirring with a magnetic rod. Crush big lumps of dispersion with a glass rod. Repeat twice.
2.Remove the last traces of petroleum ether/hexane by flushing with a gentle stream of N2 or dry compressed air. Some heating of the flask may be necessary.
3.Add DMSO (10 mL), cap, and put a needle through the septum. Stir with magnetic rod. If gentle reaction heat to 40-45°C, if not leave until the reaction calms down, then heat. You may ultrasonicate for some minutes.
4.Transfer the dimsyl sodium solution to screw cap tubes and centrifuge for a couple of minutes at ca. 3000 rpm.
5.Transfer to 10 mL serum flasks.

Comments
•The less moisture and oil that comes into the reaction the better.
•Some heat is required to start the hydrogen evolution, which must be led out via the needle. If there is water in the DMSO and bubbling in the flask takes place the needle may get clogged with NaOH and the flask can explode.
•A sediment is often obtained in the centrifugation.
•If dry gas is blown around the place of transfer no seals are required.
Source Page

shroomedalice · « **Reply #3 on:** November 23, 2009, 02:11:43 AM »

Im not sure but I have a funny feeling that when we run a current through DMSO and perchlorate ions that
we might get chlorine oxides as a by product.

still not sure on this so if you try this be aware it could be a possiblity.
for those who dont know chlorine oxides will kill you real quick.

also on the safety of this reaction is the fact that DMSO is transdermal and anything that
is contained in it will become active through the skin.
this means that salts that are only toxic via oral means now become toxic via skin contact.

Sedit · « **Reply #4 on:** November 23, 2009, 02:39:22 AM »

If this is a concern to you shroom then perhaps you could use the simular soluble salt KI. This will not produce dangerous contamination at all and will surely do completely away with the need for any Pt electrode since you will not be dealing with the pottasium chlorate.

I still must reiterate I do not feel any of this is at all nessasary and that the NaDMSO will form simular to alkoxides just with greater ease. Normaly alkoxides have the issues of azeotropes with H2O leading to lowered yeilds but the difference in boiling point here means that the water will leave as its synthesized and all you will be left with is the NaDMSO ready to add to the Styrene.

I know this is legel so I will surely research this ASAP. Just mix DMSO and NaOH and distill at the BP of H2O and measure the amount of water recovered. It should give one a great idea of the Dimsyl concentration.

shroomedalice · « **Reply #5 on:** November 23, 2009, 03:21:51 AM »

that will probably work sedit.
I always made my alkoxide via xylene alcohol and a hydroxide.
then I just distilled out the xylene to make the conversion.
maby this will work as well for DMSO.

well I have another use for the dimsyl.

ylide
the only problem being the formation of the organo phosphine.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THS-42H22BG-8Y&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=7a907348a4570b07df2cae1bc94f17db

not that hard realy react MBRP with a phenyl halide or an alkyl halide in the pressence of NiBr
then reduct with iron too organophosphine.

after reaction ylides can be recycled via reduction of the oxide formed then reaction with dimsyl again.
this way you can reuse your phosphorous saving you a lot of messy match boxes on the next run.

myself I am thinking of the triethylphosphonium ylide

this should open up another new set of reactions for us.

Sedit · « **Reply #6 on:** November 23, 2009, 03:22:49 AM »

These people are by far the leading researchers on DMSO reaction partialy due to the fact that there looking to sell you some so they want to know what its good for. Either way check out this paper that involves the Dimsyl ion from Gaylord involving various reactions associated with the formation and use of the DMSO ions.

shroomedalice · « **Reply #7 on:** November 23, 2009, 05:11:44 AM »

Another use for dimsyl is the conversion of hydroxyl groups to methyl groups (not found on gaylord)
http://www.publish.csiro.au/?act=view_file&file_id=CH9660521.pdf

first the hydroxyl is is tosylated
then tosylate is reacted with dimsyl anion
finally reduction affords a methyl group in place of the hydroxyl

Sedit · « **Reply #8 on:** November 23, 2009, 02:45:36 PM »

Naf has kindly supplied me with a reference that seems to support my logic in that removal of the formed water from the system increases the concentration of Dimsyl anions in the reaction. This is run at 150C which is more then likely not practical here since pyrolysis will possibly occure leading to higher condensation products with the formed Allylbenzene.

Quote

Acid/base reactions of DMSO and hydroxide ion, which give ris
to dimsyl anions 26, may be prominent at 150°C. The
basicity of hydroxide increases dramatically with temperature.

Source Page

If you look at the paper referenced you will see that figure 28 which is an intermediate in the chloroacetate product of #14 seems to suggest that an acid workup may indeed effect elimination simular to pyrolysis of the sulfoxide does. This all makes me sort of wounder though how they where achieving these effects since other text seems to state that pyrolysis occures rapidly at temperatures BELOW 200C and yet there running all there reactions at temperatures of 150C and up.

No matter what the reason I feel this seems to support my thinking in that if NaOH was added to DMSO and the water distilled you will be left with an extremely basic media of NaDMSO. What confuses me about the reaction mechanism in all of this is; Where does the Sodium cation go when the Dimsyl anion condenses with styrene?

{edit}

I have done a couple calculation forhow much H2O should be recovered from 50 grams of my 10% DMSO solution in a perfect world.

50grams DMSO/H2O 90% w/w = 45 grams of DMSO 5 grams H2O
45 grams of DMSO = 57.59 mols of DMSO
57.59% 1 NaOH mol = 23.03 grams of NaOH
57.59% 1 mol H2O = 10.37 grams of H2O released from NaDMSO formation.

Given the absorbed H2O of NaOH that number can be expected to be higher from 50 grams of H2O released from 90% DMSO solution.

I have also decided to include a copy of a wounderful book I have only begun to scratch the surface on. One of the main preps I have read of interest so far is the decomposition of DMSO using H2SO4 to yeild Dimethylsulfide and Formaldahyde. It also appears that this reagent is an effective methylation reagent so if proven true then it could aid in creating a safe form of methylation where the harmful reagents are made insitu. It all makes me wounder with its so many uses if I should change the name of this thread or just start a whole new one on the various reactions DMSO can be used for.

Sedit · « **Reply #9 on:** November 23, 2009, 09:20:43 PM »

Im just going to keep talking here folks feel free to jump in anytime

.

However this time I have a question perhaps someone can answer. Elemental Sodium or Potassium added to DMSO, albeit not wise to do so, will synthesis Na or K dimsyl. Why can I not do this with Lithium? Someone over at science madness made mention of this in a thread about drying DMSO but I do not understand why Lithium would not proceed the same way.

shroomedalice · « **Reply #10 on:** November 24, 2009, 12:56:48 AM »

Lithium just sits at the bottom unreactive. thats been my experiance heated it might work.

also when you do finaly get it to work there will be quite a lot of metallation of the carbon.
you will notice that when a lot of the documents that deal with lithium dimsyl that they use
complex amides. My origonal idea of straight lithium amide is flawed as this will also create
the metallation as a compeating reaction though not to the extent of pure lithium metal.
This also means that electrolisis is not an option for lithium salts.

to put it most simply though I think its got to do with how small the atom is and that its
melting point is way above Na and K.

lithium piperidides and LDA seem to be the go.

my self I would like to try lithium diethylamide and the lithium amide of diethylamine (not sure what
that would be called though)

shroomedalice · « **Reply #11 on:** November 24, 2009, 01:06:23 AM »

I also dont belive the idea of heating a caustic solution of DMSO will work. the reason being
that at the temps you are sugesting you will have a huge amount of breakdown of the
dimsyl ion into sodium sulfide.
probably best to use xylene and a vacuum to remove the water of formation.

www.gaylordchemical.com/bulletins/bulletin110b/Bulletin110B.pdf

Decomposition Rates at Different Temperaturesa) Below 25°CAt temperatures of 25°C and lower, DMSO solutions of dimsyl sodium are quite stable. Sjoberg89found no decomposition when the solution was stored as a solid at 10°C for two months. At 20°C,Price and Whiting11 found a decomposition rate of 8% per week. At 25°C, a 3 M solution of dimsylsodium in DMSO decomposed at a steady rate of 3-4% per day as evidenced by the yield obtainedwhen aliquot samples were reacted with benzophenone90 (Figure 1). Although the decomposition ofdimsyl sodium is exothermic, no temperature rise was observed when 3 M dimsyl sodium solutionwas stored one week at 25°C in a Dewar flask, i. e. the decomposition reaction was so slow thatthere were no problems of heat transfer.b) At 40°C. -50°C. As shown in Figure 1, dimsyl sodium decomposes at an appreciable rate at 40°C with 11% beinglost in one day. A similar result was reported by Lyness, O?Connor and Berry44 who observed a 9%loss in one day at 50°C.c)

At 70°C. and HigherCorey and Chaykovsky2 pointed out that dimsyl sodium solutions are best prepared at temperaturesof 70-75°C in order to obtain a sufficient rate of formation while avoiding the higher temperatures atwhich decomposition of dimsyl sodium is too rapid to be acceptable. Even at 70° C. the exothermicdecomposition of dimsyl sodium is rapid enough to require some attention if this, or a highertemperature, is to be maintained for a length of time. However, as indicated above, mostapplications of the reagent are at room temperature where very little decomposition takes place

Naf1 · « **Reply #12 on:** November 24, 2009, 01:46:07 AM »

Yes the potassium salt of DMSO is more stable than the Sodium analog and would be preferred. But heating a caustic solution of DMSO will work, Sedit posted the relevant links to the literature in the first post. It is not as straight forward as using sodamide or sodium hydride, but with careful stoichiometry to avoid hydrating the hydroxide ion. I do not know if this method will produce a high a concentration of dimsyl anion that Sedit wants,

"With a fixed concentration of base in DMSO, even an insignificant increase in the concentration
of water causes a sharp decrease in the basicity of the system due to hydration of
the highly basic hydroxide ion"

"it is possible to estimate the concentration of the dimsyl ion in the KOH--DMSO system. The
calculated value is 3-10 -4 M or approximately 1% of the concentration of the KOH in DMSO."

"Equilibrium can be attained in 5-10 min by heating
the system to 85*C~ and higher with subsequent cooling."

Basicity of saturated solutions of alkali metal hydroxides in dimethylsulfoxide
B. A. Trofimov1, A. M. Vasil''tsov1 and S. V. Amosova1
Russian Chemical BulletinVolume 35, Number 4 / April, 1986, pg.682-686

http://127.0.0.1/talk/index.php?action=dlattach;topic=315.0;attach=1075

Sedit · « **Reply #13 on:** December 08, 2009, 11:51:42 PM »

Lithium Nitride may prove to be a much simpler method for the home chemist then achiveing LiH or LiNH₂ to synthesis the Dimsyl ion. Li₃N is synthesized thru the direct combination of the elements just as LiH and LiNH₂ is yet obtaining dry Ammonia is next to impossible and im not so sure that heating Lithium and Hydrogen is such a great idea considering the big boom factor in the equation. However Nitrogen can be had for a fair price with ease. There are a couple methods for producing it and one that caught my attention recently was one where it was prepaired in mineral oil whose density lies between that of Lithium and Lithium Nitride and Nitrogen is feed into the mixture under high stirring. Since the reaction is exothermic the temperature can be controlled by the amount of Nitrogen introduced into solution. After completion of the reaction the Lithium Nitride sinks where the unreacted Lithium floats. You can also produce it by heating it in a N₂ atmosphere but for some reason this is said to produce an impure product.

Ok down to the chemistry of the reaction. Lithium Nitride is such a Powerful base its stronger the Alkali amides and Alkali hydrides like LiH. It is so powerful its able to deprotonate hydrogen itself givin this reaction according to wiki and quite a few other sources, Li₃N + 2H₂ = LiNH₂ + 2LiH. LiNH₂ reacts with DMSO to yeild LiDMSO and NH₃ and LiH yeilds LiDMSO and H₂. As you can see Lithium Nitride may prove to be an accessible reagent for the production of Dimsyl ions.

shroomedalice · « **Reply #14 on:** December 09, 2009, 03:42:18 AM »

sedit what a find

so many things can be done with this.

for starters anhydrous ammonia is possible which I am in need of now.
LAH is just adding the hydride to AlCl3
Lithium hydride is very usefull on its own.

truly a brakethrough.

totaly what I need for the curtius reaction

also useing this with bromo saf should give huge yeilds as its 100% dry.

and its so easy.

very dangerous compound though I would think.

to be able to deprotonate hydrogen makes it very very reactive.

having worked a bit with sodium metal and lithium metal and trying to make alkoxides this is
truly news to me.

lithium metal will not make alkoxides

this would most likely reduce oximes as well

it will dry ether bone dry

also as we only want a very slow stream of nitrogen it can be generated from a reaction like
decomposing hydrazine

well im now going to start looking for nice nitrogen generation reactions that are bone dry

thankyou sedit that made my day.

truly we are uncovering some of the best cladenstine procedures possible.

I never thought I would see the day I would attempt a LAH synthesis.

Sedit · « **Reply #15 on:** December 09, 2009, 04:11:44 AM »

Im with you on the LiH synthesis. I have considered it many times and then always pussied out but I feel much better about reacting the nitrogen at high temperatures with Lithium then I do with Hydrogen then further reacting the Li₃N with H₂ to progress the reaction to LiH and LiNH₂.

Really something I would like to try sometime for bragging rights if nothing else. My main concern is the reaction vessle that it could be synthesized in. Lithium is a strong enough reducing agent to pull O₂ out of SiO₂ so it would form atlest small amounts of Lithium oxides if performed in a glass and so far the only reaction vessles I have seen to produce it pure are Rhodium and Platinum group metals vessles. This is why I feel the mineral oil process is the best yet because it allows purification and suspension in a solvent keeping it reacting with the metal instead of the vessle.

Why did you suggest that Lithium does not make alkoxides when I have seen plenty of literature that speaks of its use. Here you can buy it at Sigma.

BTW Can you provide a reference for the metalation reaction of DMSO with Elemental Lithium?

shroomedalice · « **Reply #16 on:** December 09, 2009, 04:42:02 AM »

Lithium will not react with DMSO to my knowlage but lithium amide does and creates the metallation. ill
dig up a few refs for ya no probs

as for lithium in alcohol it ends up making hydroxide and I think an alkene.
but lithium amide and nitride will make alkoxide

I have tried many times to make alkoxide from lithium metal as methoxide is a bit of a pain to
get pure.

even rhodium told me it was not possible when I was back on the hive.

Sedit · « **Reply #17 on:** December 09, 2009, 04:51:36 AM »

I ask about the metalation reaction because I wounder about the ability to bubble Nitrogen into a Lithium/DMSO mixture to progress along. I know im getting a bit a head of myself but it still sounds like a possibility since I doubt N₂ and DMSO to react so as long as Lithiums reaction with DMSO is non existant or sluggish at best then its possible this could proceed further.

Everytime I have added Lithium to Methanol there has always been the indication of a reaction taking place and I doubt it all from trace water present in the reaction.

heisenberg · « **Reply #18 on:** December 09, 2009, 04:53:18 AM »

That Li3N patent is quite a find.

I suppose it's time to start pricing N2 tanks.

Just lettin' you know someone else is reading the thread Sedit.

shroomedalice · « **Reply #19 on:** December 09, 2009, 05:09:48 AM »

ill find the sucker I had a couple of refs but that was a wial ago now its like digging through the lot again

I would not try that as at the temps you are going to need to get the nitrogen to react with the lithium
you are going to have probs.

better to add an amine to the solution with lithium in the bottom.

this will work as lithium just sits there I know this becouse I have seen it my self.

I would use diethylamine or ethylenediamine.

my self I will probably use diethylamine as I have a use for it for some thing else quite interesting.

Author Topic: The Dimsyl ion and its uses in Organic synthesis. (Read 579 times)

Sedit

The Dimsyl ion and its uses in Organic synthesis.

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