Author Topic: When substituting GAA for Formic acid...  (Read 6815 times)

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unnilhexium

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Re: When substituting GAA for Formic acid...
« Reply #40 on: December 20, 2001, 04:21:00 PM »
WTF, Are you serious noj??????????  Anyway, for the benefit of those who can't get formic or wacker chems, I will post the results of the last peracetic SWIM ever intends to do.  325ml of 90% acetic, is added to 70ml of 25% h2o2.  Then comes 4ml of 32% sulfuric acid.  The flask is stoppered, thoroughly shaken, and allowed to stand for 12 hours.  At the 11 hour point, it is put in the fridge to chill.  At the same time, 70 grams of high quality isostuffrole is dissolved in 110ml acetone, and put in the freezer.  At the 12 hour point, the peracetic is dumped in a large erlenmeyer flask, sitting in an icebath, on SWIMS magnetic stirrer.  Stirring is commenced, and the iso is dripped in over the course of about 35 minutes.  At about the 1 hour point, the temp has stabilized, and the ice bath is removed,
and stirring is continued for a total of 16 hours.  The mix is divided into 3 ~200ml portions, and each flooded with 600ml cold h2o, glycol/epoxide sepped off, and each portion extracted with 3 x 35ml dcm.  Nasty emulsions formed on the first two portions, which were broken up with salt.  The extracts are combined, washed with h2o, and the solvent evaporated.  Next, 100ml of "methanol flavored heet" is added, and the solution is gently heated.  It is then added to 550ml preheated 15% sulfuric (250ml 32% sulfuric(battery acid)and 300ml dh2o).  It is gently heated and stirred for 2 hours, then flooded with 250 ml h2o, and set in a cold water bath for 20 minutes.  It is then at room temp, and dumped in a sep funnel, where the raw mdp2p is tapped off, the acid extracted with 3 x 90ml dcm.  The combined extracts are washed once with 250ml h2o, and once with 250ml 5% NaOH.  A blacklight is used on the second wash to determine the layers(the ketone layer glows green, the crap layer is black).  The mix is then evaporated of solvent and vac distilled to yield 43.7g of high quality ketone(yield ~57%).  All of SWIMS reagents were shitty OTC reagents, and swim believes that better reagents would give higher yields.
BTW, wanting to impress the hive, swim practiced VERY good lab technique on this run, as this was one of his best yields (usually got more around 45-50% yield).

Good luck

106

noj

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Re: When substituting GAA for Formic acid...
« Reply #41 on: December 20, 2001, 05:06:00 PM »
yea, well, I'm running around on eggshells here, and looking at so many various references, and watching 7 Federal agents lurking around a common locale.. I get forgetful at times. Selectively usually. Found some wood bleach at the hardware store so will attempt again over the next few days.

Anyone happen to know the concentration of the sodium hydroxide included in this a/b kit?

A theory is a tool - not a creed. -J. J. Thomson

PoohBear4Ever

  • Guest
Re: When substituting GAA for Formic acid...
« Reply #42 on: December 20, 2001, 05:24:00 PM »
Got the MSDS report on a common brand found in several hardware store chains, but have since deleted such info. from both memory inside head and inside computer.  Funny thing is that I actually ordered the report first for H2O2, but they only had NaOH listed in the report...

Those bastards,

PB

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unnilhexium

  • Guest
Re: When substituting GAA for Formic acid...
« Reply #43 on: December 21, 2001, 04:20:00 AM »
That's the same h2o2 swim uses.

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noj

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Re: When substituting GAA for Formic acid...
« Reply #44 on: December 23, 2001, 08:02:00 PM »
The product quickly takes a red color (indicating the decomposition of iso) when left to it's own devices, and yields have been terrible.  When an ice bath is used, the mix maintains a pretty orange color

unnilhexium, are you sure about this? About half way through the iso addition with acetone the solution turned almost black (red). This is the same color as is experienced when performing a wacker. The solution was maintained at 35-38°C. Are you sure the red color isn't simply a successful oxidation? According to the synth at Rhodium's we are looking to extract a dark red liquid, so it seems that this is a sign of success, and that orange would indicate a low yield.

A theory is a tool - not a creed. -J. J. Thomson

unnilhexium

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Re: When substituting GAA for Formic acid...
« Reply #45 on: December 23, 2001, 11:26:00 PM »
When you flood the mixture with water, the epoxide/glycol that separates out is red, if that is what you are refering to.  But I'm actually pretty sure about this one.  Also, swim maintains a temp well below 35C (with the help of an icebath, and chilling the isosass and peracetic).  I don't remember the post#, but I remember rhodium(I think it was rhodium) stating that the red color from the reaction is caused by the decomposition of isosafrole.  Or then again, maybe I've finally managed to fry my brain.  Either way, all swim can say is that he has not seen a higher peracetic yield(57%), than the one he posted, and that swims brand of rolls are the most sought after in all the land.

106

unnilhexium

  • Guest
Re: When substituting GAA for Formic acid...
« Reply #46 on: December 24, 2001, 11:04:00 AM »
BTW, all of the high yielding buffered performic write ups that swim has read(and will be dreaming soon), have said that the extracts are an orange color.  However, that brings swim to a question:  If the classic performic and buffered performic both give quantitative yield of the intermediate, then is the higher yield from the buffered reaction the result of:  A)residual sodium bicarbonate buffering the hydrolisis, or B)the epoxide, which is more prevalent in the buffered performic, has a higher yield in the hydrolisis than the glycol?  Any thoughts?

106

Chromic

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Re: When substituting GAA for Formic acid...
« Reply #47 on: December 24, 2001, 11:28:00 AM »
I bet it's that the bicarbonate encourages the peracid to breakdown, increasing it's activity... uping the yields of the performic. Judging by the mechanism, the glycol and the epoxide would give exactly the same yield (assuming hydrolysis of the epoxide is done in quantative yield) The H2SO4 hydrolysis has about an 80% yield, I'm unsure of the performic, but I'd imagine it to be around 80% as well... giving an overall yield of about 65%.

noj

  • Guest
Re: When substituting GAA for Formic acid...
« Reply #48 on: December 27, 2001, 05:40:00 PM »
Ok, I guess I did do the 15% rearrangement. I believe the fault was with the peroxide.

Speaking of peroxide, while vacuum distilling the ketone, I noticed a crystalline formation inside the condenser. Fearing what is called acetone peroxide, I tried to wash it out with water. No luck. So I tried using the chem finder to see the nature of this substance. Also no luck. Reading this thread I see that it is soluable in acetone, and that worked. Under vacuum it appeared sometime between 40° to 140°C. Is there another name for this acetone peroxide? And would continued distillation be okay? Don't have a blast shield and insurance doesn't cover explosions from drug synthesis. Under what conditions does it explode?


A theory is a tool - not a creed. -J. J. Thomson

Ritter

  • Guest
buffered performic -> monoformyl glycol
« Reply #49 on: December 27, 2001, 08:14:00 PM »
I have verifiable proof that the buffered performic rxn can provide practically quantitative yields of monoformyl glycol.  Back in the day when I used to dream of this rxn, SWIM used to check the mass of the orange syrup resulting when DCM was stripped (using high-vacuum) from oxidation product to make sure the rxn went to completion to provide maximum yields.  I don't remember exactly what the atomic mass of isosaf monoformyl glycol is, but 210 comes to mind.  Therefore if the oxidation of 1mol of isosaf(162g) produced 210g of product, the intermediate was ready for acid hydrolysis.  Sometimes yields were less if the peroxide was bad or whatever, and in these cases the formylglycol was re-dissolved in DCE and subjected to additional performic acid and sodium carbonate (yes I am anal  :)  ).  This always brought the mass up to the expected 210g/mol.  Acid pinnacol-rearrangement can yield up to 85% ketone.  Much ketone is usually destroyed during standard vacuum distillation, however there are techniques to minimize thermal decomposition providing those ultra-high yields.  They are for me to know and you to find out! :P

terbium

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Re: When substituting GAA for Formic acid...
« Reply #50 on: December 27, 2001, 09:42:00 PM »
Is there another name for this acetone peroxide?
I am more familar with Methyl Ethyl Ketone peroxides. I figure that acetone peroxides are about the same.

The thing is that (with MEK) there is more than one. There is methyl ethyl ketone hydroperoxide which (in a diluted form) is an article of commerce. I have never seen pure MEK hydroperoxide, I had always assumed that it is a liquid. Then there are also other organic peroxides that can be formed from the reaction of methyl ethyl ketone and hydrogen peroxide with acid catalyst; these other peroxides are probably some polymeric form, perhaps a dimer or trimer. These polymeric forms are extremely shock sensitive.

It would be a very good idea to test for any remaining active oxygen (peroxide) in your reaction product to be certain that it has all been destroyed before attempting a distillation. Perhaps shaking with a freshly prepared aqueous solution of ferrous sulfate would be a good way to destroy an remaining peroxide in the ketone prior to distillation.

Chromic

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Re: When substituting GAA for Formic acid...
« Reply #51 on: December 27, 2001, 10:24:00 PM »
Yeah, I imagine the yields of isosafrole monoacetyl glycol are similar to isosafrole monoformyl glycol. Too bad there isn't a better (easy) way to affect rearrangement than a 15% H2SO4 rearrangement.

Rhodium

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Re: When substituting GAA for Formic acid...
« Reply #52 on: December 28, 2001, 12:01:00 AM »
It would surely work to use p-toluenesulfonic acid in a small amount, as it is organic soluble? Has this been tried?

Chromic

  • Guest
Re: When substituting GAA for Formic acid...
« Reply #53 on: December 29, 2001, 05:36:00 AM »
Hmm, I wish I could experiment with some, but I've got no access to even common organic reagents.

I just reread Tao Corning's post on the peracetic... I guess my trials with uping the H2O2 and AcOH would likely have solved (or at the minimum, helped) his problems. I also wonder what Semtex's ketone->amine yields were on his peracetic? He never posted them.  :(