Author Topic: The Dimsyl ion and its uses in Organic synthesis. (Read 582 times)

Sedit · « **Reply #20 on:** December 10, 2009, 04:01:24 AM »

I tracked this down to find out that it had been posted at Science Madness sometime ago but the link was dead. The person that posted the link kindly retrieved the file for me as well. It is about the synthesis of "Super bases" and Proton sponges. Even though I have yet to see one thats as strong as we need there are quite a few that are damn close but are pretty complicated.

Non the lest I will post it for all your reading pleasures. Im sure theres a little something for everyone in this book.

Enkidu · « **Reply #21 on:** May 09, 2011, 05:00:19 AM »

Quote from: Sedit 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.

A quick mention of the preparation of the 3-phenylpropyl methyl sulfoxide intermediate is made in this paper.

Potassium Hydroxide Catalyzed Addition of Arylamines to Styrenes
Daniel Jaspers, Sven Doye
SYNLETT 2011, No. x, pp 000A–000Ex.x.201 Advanced online publication: xx.xx.2011. 7 February 2011
DOI: 10.1055/s-0030-1260555

shroomedalice · « **Reply #22 on:** June 15, 2011, 02:08:59 PM »

you gave me an idea enkidu

what if we were to use KOH DMSO styrene and xylene in a dean stark setup.

would not the removal of water push the dimsyl reaction forward ?

maby we could even do with out the xylene and use styrene as the azeotrope for water
removal

Sedit · « **Reply #23 on:** June 15, 2011, 08:17:07 PM »

Yes, check the reference request thread or I will check for you later, Someone over at Science madness gave me some papers that suggest that KOH or Alkoxides move in favor of the addition product anyway even without a dean stark trap. It seems to confirm my theory that as the Dimsyl is used up in the addition reaction new Dimsyls fill the gap. The speed of the reaction should be proportional to the PKA of the base used.

If its the Dimsyl your after then I would suggest to use EtOH as its alkoxide would favor more Dimsyl ions and it would carry water away as it was distilled off.

I was recently going to test this but Styrene has vanished from the stores making it just one more complication in the experiments to acquire styrene.

Enkidu · « **Reply #24 on:** June 15, 2011, 08:23:39 PM »

To prevent the obvious unwanted side rxn (the addition of DMSO across the target propene), the rxn must be run at a cold temp to prevent the decomposition of the intermediate sulfoxide. The intermediate sulfoxide should be separated from the reaction mixture and decomposed on its own for ease of workup.

I'm not sure that using ethanol would be a good idea because the hydroxide and the ethoxide will be busy deprotonating each others conjugate acids instead of deprotonating the DMSO. I'm honestly not sure how that equilibrium will work. It may depend on the concentration of the species in equilibrium.. so, in that case, you'd only want a little ethanol?

Enkidu · « **Reply #25 on:** June 15, 2011, 10:48:37 PM »

Quote from: Sedit on June 15, 2011, 08:17:07 PM

Yes, check the reference request thread or I will check for you later, Someone over at Science madness gave me some papers that suggest that KOH or Alkoxides move in favor of the addition product anyway even without a dean stark trap.

Please link me.. a search for DMSO revealed nothing [of use] in the SM ref req thread.

Sedit · « **Reply #26 on:** June 16, 2011, 12:13:42 AM »

Enkidu I believe you are the one that retrieved it for me here, I will check later but its in our reference request thread the discussions where just private messages with someone over at science madness pointing me in the right direction.

Enkidu · « **Reply #27 on:** June 16, 2011, 01:09:19 AM »

Is this the ref you indicate? It's already listed in your first post. Do me a favor and back up your statements with references instead of sending people on wild goose chases cuz of sloppy posting

http://127.0.0.1/talk/index.php/topic,315.msg7274.html#msg7274

Sedit · « **Reply #28 on:** June 16, 2011, 02:27:41 AM »

Sloppy posting?

Beg your fucking pardon but I have been a very busy person today and I was doing nothing but answering Shrooms question. Just because your to incompetent to find it yourself don't mean that my post was bad.

Now, I will go looking for the reference now because my responsibilities are asleep, so please, set your bottle down for a second and ill be right back. Try not to drink yourself into oblivion before I get back OK.

OK im back, now... that didn't take so long did it? Naaa....

http://127.0.0.1/talk/index.php/topic,2024.msg21542.html#msg21542

Or.... you can scroll down about three fucking post to the one you made and uploaded the G'damn paper to. I told you I didn't have time, whats your excuse? You where the one that uploaded it sheesh....

Now the side reaction is all they mention it as but what would be needed is at lest a stoichiometric amounts of strong base to yield Allyl benzene and Propylene Benzene as the primary product.

Quote

This byproduct
is obviously formed by proton abstraction from DMSO and subsequent addition of the corresponding anion to styrene (Scheme 1).

This competitive reaction is favored
when no suitable amine as reaction partner is present and
occurs even at room temperature.

Now... I believe I received two references around that time piggy backing each other so once again I will go hunting for it.

Enkidu · « **Reply #29 on:** June 16, 2011, 02:45:23 AM »

I WANTED A NEW PAPER

Sedit · « **Reply #30 on:** June 16, 2011, 02:50:36 AM »

No need for a new paper when the old ones have your answers in them

. I want a bunch of new ones too but this reaction just has not been studied as much as I wish it was, its very very powerful.

Quote from: Enkidu on June 15, 2011, 08:23:39 PM

To prevent the obvious unwanted side rxn (the addition of DMSO across the target propene), the rxn must be run at a cold temp to prevent the decomposition of the intermediate sulfoxide. The intermediate sulfoxide should be separated from the reaction mixture and decomposed on its own for ease of workup.

I'm not sure that using ethanol would be a good idea because the hydroxide and the ethoxide will be busy deprotonating each others conjugate acids instead of deprotonating the DMSO. I'm honestly not sure how that equilibrium will work. It may depend on the concentration of the species in equilibrium.. so, in that case, you'd only want a little ethanol?

Perhaps but given the PKA of Potassium Ethoxide the addition of a drying agent such as CaO here would without a doubt force this equilibrium to the right. More then likely this will happen faster then I anticipated given there mention how the Sulfoxide addition product is the main on in the absence of an amine. They also mention it happens at room temperature so that would mean that without a doubt the use of CaO/EtOH+KOH would speed this little fellow along rather nicely and all one would have to do is wait for the equilibrium to setup as the CaO is converted into its hydroxide as it gobbles up water.

PS: Thanks for pissing me off, its got my mind cleared and I now see that this is by far the holy grail of AMPH synthesis. Allylbenzene bucket chemistry by the gallon, it really does not get any better then this.

Enkidu · « **Reply #31 on:** June 16, 2011, 09:20:38 AM »

J. Am. Chem. Soc., 1973, 95 (20), pp 6840–6842, "New synthetic reactions. Sulfenylation-dehydrosulfenylation as a method for introduction of unsaturation" states the the "thermolysis of the a-methylsulfinyl derivative of ethyl decanoate was studied in some detail. At temperatures below 120*, elimination was sluggish. At 120*, 5 hr was required. In refluxing toluene, completion occurred in about 14 hr. No difference in yield was noted for the two methods."

===

Pyrolysis of unsymmetrical dialkyl sulfoxides. Rates of alkene formation and composition of the gaseous products
David W. Emerson, Arthur P. Craig, Irvin W. Potts Jr.
J. Org. Chem., 1967, 32 (1), pp 102–105 DOI: 10.1021/jo01277a026

===

J. Org. Chem., 1975, 40 (13), pp 2014–2016, "Alkylative eliminations. Scope of the activating group"
says that elimination was effected by raising the temperature of THF to reflux.

===

shroomedalice · « **Reply #32 on:** June 16, 2011, 01:25:12 PM »

personaly ive got a nice stark setup and styrene is abundant in oz so when time permits/ if it permits
ill see what happens.

personaly not my thing styrene too propenyl benzene but we have been kicking this around
for a wial now sedit so if I can give it a go I shall.

scary what could be done with it if it worked though hehe ;P

Sedit · « **Reply #33 on:** June 16, 2011, 01:39:06 PM »

Yeh use the dean stark setup, I don't know if i'm reading this wrong or if they only used the DS on some of the reactions but they do make mention of it at the very end.

Interesting to note table 2-example 8, Its a direct hydroamination of a propenylbenzene yet it only occurs in low yields. That reaction was run for 24 hours and still only obtained 6%

. Perhaps this is the result of hinderence due to the bulky nature of the arylamines and I would love to see if any of these reactions worked using Methylamine or some other amine source.

By all means please give it a go Shroom you know im dying on this one. I have got motivated to perform this reaction two times now, the first I could not get my DMSO even slightly dry and recently I went to get styrene for safe keeping and possibly start messing around only to find its no longer being sold here.

Enkidu · « **Reply #34 on:** June 16, 2011, 08:52:36 PM »

From Chem Comm 1965, (2), p.29, "Pyrolysis of alkylsulphoxides,"

Quote

Treatment of the anion of dimethyl sulphoxide with a normal [long chain aliphatic] primary bromide, R-Br for 3 hours at room temperature gave good yields of the sulphoxide, R-SOCH3, usually crystalline. Pyrolysis of the sulphoxide to the vinyl olefin was conveniently carried out by refluxing in dimethyl sulphoxide. For example, the sulphoxide was obtained in 73% yield. Refluxing this sulphoxide for 30 minutes in dimethyl sulphoxide afforded tridec-1-ene (80%).

===

From what I've read, I don't really like the following patent (patents often turn out to be BS), but apparently hydroxide works fine. They claim sodium hydroxide causes the rxn to fail.

GB1085198A Process for the production of araliphatic sulphoxides

Quote

The title compds. are prepd. from a substituted styrene with a sulfoxide at 75-150° in the presence of KOH. Thus, to 500 ml. tech. Me2SO is added 56 g. powd. KOH and the mixt. is heated with stirring to 115-20°. To this mixt. is added at 115° dropwise with stirring in 1 hr. 104 g. styrene, and the mixt. is kept 1 hr. at 115-20° with stirring and worked up to yield 83.5% crude methyl ?-phenylpropyl sulfoxide (I), m. 44-5° (cyclohexane-C6H6), b0.01 143-5°, b0.2 156°. Similarly is prepd. methyl 3-phenylbutyl sulfoxide, b0.1 145-50°.

nk40ouvm · « **Reply #35 on:** June 18, 2011, 02:56:55 AM »

Quote from: Enkidu on June 16, 2011, 08:52:36 PM

From what I've read, I don't really like the following patent (patents often turn out to be BS), but apparently hydroxide works fine. They claim sodium hydroxide causes the rxn to fail.

GB1085198A Process for the production of araliphatic sulphoxides
Quote
The title compds. are prepd. from a substituted styrene with a sulfoxide at 75-150° in the presence of KOH. Thus, to 500 ml. tech. Me2SO is added 56 g. powd. KOH and the mixt. is heated with stirring to 115-20°. To this mixt. is added at 115° dropwise with stirring in 1 hr. 104 g. styrene, and the mixt. is kept 1 hr. at 115-20° with stirring and worked up to yield 83.5% crude methyl ?-phenylpropyl sulfoxide (I), m. 44-5° (cyclohexane-C6H6), b0.01 143-5°, b0.2 156°. Similarly is prepd. methyl 3-phenylbutyl sulfoxide, b0.1 145-50°.

Very nice find, if it's true. Changing the cation from sodium to potassium does have a surprisingly large effect in some reactions (see e.g. the big potassium-from-KOH-and-magnesium thread on SM).

There is a related difference between NaOH and KOH that might explain why the patent works, or alternatively, highlight a trap for those not "skilled in the art."

Potassium hydroxide has a stronger affinity for water than sodium hydroxide at high concentrations, so that anhydrous KOH is rare and requires special measures to prepare. KOH flakes or pellets contain a fair bit of water compared to NaOH, ~15-25% or so. In older literature that references "anhydrous potassium hydroxide" they are probably speaking of low-water-content hydroxide, prepared by strong heating of the usual KOH in silver dishes.

Presuming that the patent works, I wonder if it has something to do with relative water affinity. Even though it's not mentioned in the patent, it's possible that the authors pretreated the KOH by strong heating to drive off water and make it a more powerful water-binder. I think that omitting that bit of information would be fair play under the usual "known to those skilled in the art" clause. Or it's possible that it is simply the change of cation that's needed, no special KOH pretreatment necessary, or that the patent is simply bunk.

But if the first attempt with off-the-shelf KOH fails it's worth considering that the KOH may just need pretreatment to reduce its water content.

Enkidu · « **Reply #36 on:** June 18, 2011, 06:34:14 AM »

Thanks for your response. The part of the patent with which I at first disagreed was the temperature of the rxn. Notice that some groups use temperatures as low as 70*C to decompose the sulfoxide. This could be due to some type of base mediated elimination involving the sodium ion. After re-reading a little, I think that the sulfoxides start to decompose much, much more quickly at 120*C, so it makes sense to hold the rxn at 115 or 110 for quick completion. However, I would rather use a longer rxn time and a lower (and safer for the chemist) temperature for an end product of higher purity.

Here is the relevant quote from the patent,

Quote from: GB1085198A Process for the production of araliphatic sulphoxides

The fact, that an addition can be brought about in the presence of potassium hydroxide acting as a catalyst must be considered especially surprising because it was not known that alkali metal hydroxides are really suited for converting methyl sulphoxides into the corresponding deprotonated methyl sulphoxide anions and that the addition reaction does not take place with sodium hydroxide. Moreover, using potassium hydroxide, the reaction temperatures are higher than in the known utilization of sodium hydride or alkali metal alcoholates and thus already come within the range of the pyrolytic decomposition temperatures of the reaction products. However as may be gathered from the high yields of the process under this invention, this decomposition does not take place under the reaction conditions of the invention.

Sedit · « **Reply #37 on:** June 18, 2011, 06:45:16 AM »

Quote from: nk40ouvm on June 18, 2011, 02:56:55 AM

Presuming that the patent works, I wonder if it has something to do with relative water affinity. Even though it's not mentioned in the patent, it's possible that the authors pretreated the KOH by strong heating to drive off water and make it a more powerful water-binder. I think that omitting that bit of information would be fair play under the usual "known to those skilled in the art" clause. Or it's possible that it is simply the change of cation that's needed, no special KOH pretreatment necessary, or that the patent is simply bunk.

While possible I am more inclined to feel its more to do with the PKA of the base then its water binding ability. However deep down inside these two things kind of go hand and hand. Can we not just distill the water off once the KOH is added to the DMSO?

Enkidu · « **Reply #38 on:** June 18, 2011, 07:19:52 AM »

Yes if you're using KOH; probably not if you're using other bases. Example 2 in the patent describes adding the KOH to the DMSO and boiling off a quarter of the DMSO to remove water. Note that this happens before the addition of the styrene.

Components\|	Boiling point, *C\|	Azeotropic B.P, *C\|	Composition in azeotrope
Water	100.00	93.90	40.90
Styrene	145.20		59.10

http://www.chemeng.ed.ac.uk/people/jack/azeotrope/hetero.html#s

According to this properties sheet, the solubility of potassium hydroxide in DMSO is about three times lower than sodium hydroxide.

Edit: The paper in this post, Basicity of saturated solutions of alkali metal hydroxides in dimethylsulfoxide, Russian Chemical Bulletin Volume 35, Number 4 / April, 1986, pg.682-686 is especially enlightening.

shroomedalice · « **Reply #39 on:** June 18, 2011, 10:29:26 AM »

my thoughts would be to do the reaction under vac as xylene will azeotrope water fine at 30 too 40 C.
still a little bit of dicking around would be in order as running a dean stark under vac would mean that unless
it was dripping into a vacuumed enviroment it will suck air into the reaction rather than letting the water out.

so a two neck flask that is also under vac with the first neck attached to the vac and the second attached
to the dripper of the dean stark would be the go.

not too hard realy.

Author Topic: The Dimsyl ion and its uses in Organic synthesis. (Read 582 times)

Sedit

Re: The Dimsyl ion and its uses in Organic synthesis.

Enkidu

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shroomedalice

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Sedit

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Enkidu

Re: The Dimsyl ion and its uses in Organic synthesis.

Enkidu

Re: The Dimsyl ion and its uses in Organic synthesis.

Sedit

Re: The Dimsyl ion and its uses in Organic synthesis.

Enkidu

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Sedit

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Enkidu

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Sedit

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Enkidu

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shroomedalice

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Sedit

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Enkidu

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nk40ouvm

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Enkidu

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Sedit

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Enkidu

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shroomedalice

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