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Author Topic: Short Question Thread 2.0  (Read 5706 times)

gloves

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Re: Short Question Thread 2.0
« Reply #40 on: April 26, 2012, 11:10:01 AM »
Quote from: GreenD on April 24, 2012, 08:26:16 PM
Although I haven't done the methylation, the decarboxylation is very difficult unless one has ethyl acetate. . . You also need stoichiometric amounts of ketone catalyst. Acetophenone is the best solvent for this reaction, it can give quantitative yields.

Methylation is easy, if you have DIPEA.

Why ethyl acetate? It boils at just 77°C, which is hotter than what it takes a simple ketone like acetone to boil, but I thought you'd need a solvent which takes more degrees than say boiling water to achieve the decarboxylation.

salat

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Re: Short Question Thread 2.0
« Reply #41 on: April 26, 2012, 01:29:30 PM »
Sometimes a solvent serves to remove excess heat from the reaction mix.  When the solvent is cooled and falls back in it cools the surrounding mix.  The maintenance of temperature in a reaction is an art in itself. 



Salat

gloves

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Re: Short Question Thread 2.0
« Reply #42 on: April 26, 2012, 07:44:44 PM »
Quote from: salat on April 26, 2012, 01:29:30 PM
Sometimes a solvent serves to remove excess heat from the reaction mix.  When the solvent is cooled and falls back in it cools the surrounding mix.  The maintenance of temperature in a reaction is an art in itself.

I think you're referring to reflux with a Vigrex or similar column, right? Do you think ethyl lactate would do too in this reaction? I thought the solvent had to stay liquid during the decarboxylation, though if you say so, wouldn't excess acetone work too if refluxing?

fresh1

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Re: Short Question Thread 2.0
« Reply #43 on: April 27, 2012, 09:06:02 AM »
i think salat is referring to the fact that UNTIL the solvent/s with the lower points have evaporated off, it will be difficult for the reaction to exceed the temperature of the lowest BP solvent/compound

   The point salat is suggesting is that the ethyl acetate may be being used intentionally to control the temperature of the reaction mix in some ways (until its all gone)  which sounds like a strong possibility  :-\

   and if I read you right, you, gloves are wondering how such a low BP solvent can be used in a Rxn you think needs to proceed above 100c to occur...
    I am not sure if it does 'need' to exceed 100c (maybe someone else can chime in here  ;D )

  Dont forget that mixtures of liquids and/or solvents, will have a different BP (most likely higher) than just pure ethyl acetate alone.

 Does this help?
« Last Edit: April 27, 2012, 09:14:10 AM by fresh1 »
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Sydenhams chorea

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Re: Short Question Thread 2.0
« Reply #44 on: April 27, 2012, 10:46:46 AM »
Quote from: GreenD on April 24, 2012, 08:26:16 PM
Quote from: twitch on April 24, 2012, 03:53:59 PM
Quote from: gloves on April 21, 2012, 12:00:20 PM
Did the proposed DMT synthesis thru decarboxylation of amino acids in ketones prove to be valid?

One needs to methylate after decarboxylation. But yes, the decarboxylation is catalysed by the presence of ketones, and some essential oils (depending on your oils there can be side products) Any high boiling point nonpolar solvent should do, xylene, or benzophenone, ketones will speed it along. Also, that's the easy bit! Methylation is the tricky part.

Although I haven't done the methylation, the decarboxylation is very difficult unless one has ethyl acetate. . . You also need stoichiometric amounts of ketone catalyst. Acetophenone is the best solvent for this reaction, it can give quantitative yields.

Methylation is easy, if you have DIPEA.

DIPEA? What are you talking about? Methylating tryptamine will result in the quaternary salt.
It is perhaps the narcotic. Hyoscine affects certain people very oddly. One cannot be sure. Sometimes, these cases take strange forms. The victim becomes in a sense, 'mediumistic', a vehicle for all the intangible forces in operation around her.

salat

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Re: Short Question Thread 2.0
« Reply #45 on: April 27, 2012, 02:13:05 PM »
Reflux is very different from Distillation, which is what you use to get a something out of the reaction mix, in which case you are taking the solvent out.

In a reflux you have the condensor straight up over the reaction flask so that the solvent evaporates then condenses back into the flask continuously until the reaction is done. 

When they say it acts as a heat sink they mean that heat is carried out of the flask by the solvent vapor - is then cooled to liquid by the condenser and falls back into the flask at a much cooler temp than it left it.  When it mixes with the contents of the flask it lowers the temp overall by some small amount.  Temperature is not usually uniform throughout a flask so you will have parts which are hotter than others no matter how good your stirring is.


Salat
« Last Edit: April 27, 2012, 02:15:56 PM by salat »
Salat

gloves

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Re: Short Question Thread 2.0
« Reply #46 on: April 27, 2012, 03:41:30 PM »
Thank you all for your replies, I however already knew the difference between reflux and distillation  :)

If tryptophan decarboxylation requires just heating in a suitable solvent in presence of a ketone, won't using acetone both as a catalyst and solvent work? Or using ethyl lactate and acetone, which are both easier to find?

Polonium

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Re: Short Question Thread 2.0
« Reply #47 on: April 27, 2012, 07:36:56 PM »
Attached is a reference where the decarboxylation of Tryptophan is attempted in various OTC solvents with a number of different ketones used as catalysts. The yield with acetone as the catalyst doesn't exceed 25% although it doesn't look like it was used also as a sovlent.

Have a look, its very comprehensive. The guy that did the study is very involved with one of the other clandestine chemistry sites. Seems like a pretty cool dude! One of the references in the article is the Rhodium Archive :)

salat

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Re: Short Question Thread 2.0
« Reply #48 on: April 27, 2012, 08:01:57 PM »
Quote
I however already knew the difference between reflux and distillation

Was referring to fresh1's post where he says evaporation of solvent - which isn't consistent with reflux so that is why I explained it.
Salat

gloves

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Re: Short Question Thread 2.0
« Reply #49 on: May 01, 2012, 12:36:21 PM »
Quote from: Polonium on April 27, 2012, 07:36:56 PM
Attached is a reference where the decarboxylation of Tryptophan is attempted in various OTC solvents with a number of different ketones used as catalysts. The yield with acetone as the catalyst doesn't exceed 25% although it doesn't look like it was used also as a sovlent.

Have a look, its very comprehensive. The guy that did the study is very involved with one of the other clandestine chemistry sites. Seems like a pretty cool dude! One of the references in the article is the Rhodium Archive :)

Thanks for the references  ;D figuring out how much are X mmol of a mix of compounds (natural oils) is the most challenging stuff in that paper.

newbiechem

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Re: Short Question Thread 2.0
« Reply #50 on: May 03, 2012, 04:19:27 AM »
quick question pleaseeee

is methylamine hcl soluble in water? tryed to dissolve 70gr in 70gr h2o but had alot undissolved  :o is it normal? or could be amonium chloride contamination from previous reaction?

thanks alott

DopeBee

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Re: Short Question Thread 2.0
« Reply #51 on: May 03, 2012, 06:47:55 AM »
Quote from: newbiechem on May 03, 2012, 04:19:27 AM
is methylamine hcl soluble in water?
Very. Try dissolving in warm water though, as the dissolution is endothermic which lowers solubility.

newbiechem

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Re: Short Question Thread 2.0
« Reply #52 on: May 03, 2012, 03:47:44 PM »
well the matter is that mine didnt dissolve, so.... i believe most of what didnt dissolved was amoniumchloride probely.
hot IPA will dissolve methylamine but not the amonium right? so colect methylamine from IPA when cold?
thanks alot

Piglet

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Re: Short Question Thread 2.0
« Reply #53 on: May 11, 2012, 03:17:44 PM »
Can one use 1,2dichloro-ethane in place of chloroform in a schmidt reaction? Or any other substituents?
Many thanks!
...walking the middle path

Electro´S

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Re: Short Question Thread 2.0
« Reply #54 on: May 11, 2012, 09:25:37 PM »
Just making Numbers.  :)
I saw Salat post about "Bromination HBr in GAA".
2:1 NaBr/KBr to oil
0.5:1 H2SO4 (actually, just a hair less than equimolar)
?:1 GAA (see METHOD for determination)
Can any one help me showing me if the GAA amounth is right? :-[
100mmol=>16,2g Safrole
210mmol=>21,5g NaBr---25,05 KBr  =>(16,7g Br = 17,7g HBr)
100mmol=>9,8g H2SO4 (a little less equimolar to keep some Br salt undissolve without Sulfuric Acid around Safrole)
295mmol=>17,7 g GAA  =>(17,7g HBr +17,7 GAA) = 35,4g 50%HBr-GAA.
Thanks!!! ;D
edit: Sorry, i forgot something:The mass of GAA is equal to the mass of HBr for a 50% concentration.
Much Thanks Salat!!!
« Last Edit: May 11, 2012, 10:48:45 PM by Electro´S »

lugh

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Re: Short Question Thread 2.0
« Reply #55 on: May 11, 2012, 09:51:55 PM »
Quote from: Piglet on May 11, 2012, 03:17:44 PM
Can one use 1,2dichloro-ethane in place of chloroform in a schmidt reaction? Or any other substituents?
Many thanks!

Some Schmidt reactions are done in dichlormethane, so it's probable that dichlorethane could be used as well  8)
Chemistry is our Covalent Bond

salat

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Re: Short Question Thread 2.0
« Reply #56 on: May 11, 2012, 10:41:14 PM »
I asked the chemist in the family to check your math and he says it's fine. 

I notice that you seem concerned about sulfuric in contact with safrole - note that you don't add your safole until you have finished creating your 50% Hydrobromic acid so the sulfuric acid should be used up by then. 

Do be sure and keep this as cool as you can and be wary of fumes.  If you have any questions due to translation issues please PM me.

Salat

Piglet

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Re: Short Question Thread 2.0
« Reply #57 on: May 12, 2012, 12:18:43 PM »
Thank you lugh. I will try.

Is it possible to request a reference of these 2 papers from somebody with university access (anyone know where the references?
(I try to access http://127.0.0.1/talk/index.php/topic,2556.msg26266.html#new , but I get error - The topic or board you are looking for appears to be either missing or off limits to you.)

http://www.sciencedirect.com/science/article/pii/S0040403900818882
http://dx.doi.org/10.1111%2Fj.1365-2133.2008.08464.x
...walking the middle path

Polonium

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Re: Short Question Thread 2.0
« Reply #58 on: May 12, 2012, 06:50:55 PM »
Here you go piglet.

Silver(I)/persulfate oxidative decarboxylation of carboxylic acids. Arylacetic acid dimerization.
William.E. Fristad,  Jeffrey A. Klang
Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455 U.S.A.
http://dx.doi.org/10.1016/S0040-4039(00)81888-2

In vivo evaluation of piperine and synthetic analogues as potential treatments for vitiligo using a sparsely pigmented mouse model.
Faas, L., Venkatasamy, R., Hider, R.C., Young, A.R. and Soumyanath, A.
(2008), British Journal of Dermatology, 158: 941–950.
doi: 10.1111/j.1365-2133.2008.08464.x

You need 10 posts to view the references section. You'll get there soon ;)

Electro´S

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Re: Short Question Thread 2.0
« Reply #59 on: May 13, 2012, 05:54:36 AM »
Hi, a new survival questions!
Reducing P2NP with Hg/Al with IPA and GAA. What is the best way to get a slow rate reaction?.
Sometimes the cat of my dreams try to make thick Al with thin foil, making 5 cm squares of 15-20 layers, and them chopped in a blender just seconds.
Other times it add mercury salt (In GAA) to the reaction in a couple of times, (when the hidrogen liberated amounth is going down, a little bit more of mercury solution is added to the reaction)
It had learn than the volcano reaction during reduction can be controled if it put the flask in a water bath from the beguinning.
The reason why it wants a slow rate reduction is because it allways end with fair yields. The yields of amine salt obtained is just half  of P2NP amounth placed on the reaction or even a little less  :'(. And it thinks may be is for the fast and extreme exotermic start of the reaction.
Any suggestion to boost yield a little bit more.
Thanks!!!  :D
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