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Author Topic: isomerization by base + PTC  (Read 181 times)

aniracetam

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isomerization by base + PTC
« on: April 14, 2011, 05:20:57 AM »


of course, in the known scheme the PTC is tetrabutylammonium hydroxide.
could a quaternary ammonium hydroxide be substituted with a quaternary ammonium chloride, such as adogen 464?
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letters

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Re: isomerization by base + PTC
« Reply #1 on: April 17, 2011, 11:19:59 AM »
no experience with this type of substrates, but in general the chloride ion may pose a threat to what seems like a fragile quadcyclic system. I vaguely recall reading somewhere that chloride ions decompose lsd, which is why tap water is bad for it. but that might be a myth.
« Last Edit: April 20, 2011, 04:16:11 PM by letters »

JustDreaming

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Re: isomerization by base + PTC
« Reply #2 on: November 24, 2011, 10:57:04 PM »
How about choline bitartrate?

Quote
Choline hydroxide is one of the class of phase transfer catalysts that are used to carry the hydroxide ion into organic systems, and, therefore, is considered a strong base. It is the least costly phase transfer catalyst, and is used as a cheap method of stripping photoresists in circuit boards. Choline hydroxide is not completely stable, and it slowly breaks down into trimethylamine.

edit -
@letters - now is it chloride ion's or is it chlorine/chloramine? I've never heard anyone mention chloride only chlorine. edit - I'm often mistaken but I believe in the POCl3 synthesis(a la Shulgin) the NH4OH is added to remove the hydrochloride and thus form the free-base(meaning there will be Cl- bouncing around to form the hydrochloride from the nucleophilic substitution and post-basification). The thionyl chloride route works a similar way. I don't think Cl- is the culprit as a bluelighter has suggested, but again my knowledge is incredibly limited.
« Last Edit: November 25, 2011, 05:00:07 AM by JustDreaming »
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akcom

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Re: isomerization by base + PTC
« Reply #3 on: November 25, 2011, 05:52:16 AM »
The only way to tell for sure is experimentation.  Yields for reactions involving quat. ammonium salts can vary wildly between salts.

aniracetam

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Re: isomerization by base + PTC
« Reply #4 on: November 25, 2011, 06:15:22 AM »
yes, I know.

btw, here's the paper describing the adsorbtion of Adogen 464 onto silica; separations can be done at a pH of 8 with it.
another possibility is pretreatment of the silica bed with triethylamine, a common practice; the stationary phase may also serve as a medium for the adjoining of adducts.
« Last Edit: November 25, 2011, 06:22:42 AM by aniracetam »
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JustDreaming

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Re: isomerization by base + PTC
« Reply #5 on: November 26, 2011, 01:59:18 AM »
I am aware that a lot of patents are bogus as I know many of you are as well.

However this patent seems quiet real: 2005082902

The idea is that though the yield is ~70% v.s. the 80% of tetralkylammonium hydroxides, it can of course be recycled into subsequent runs and has less epimerization. Of course, if these examples are real examples(I'd imagine they are).

Kind of surprising people were boiling paspalic in alkali water knowing how sensitive to heat and base it is(hence 25% isomerization).

Furthermore the patent holder also wrote: Ergot: The Genus Claviceps (ISBN: 905702375X ), and works for a pharmaceutical company. I'd imagine the information is legitimate :).
« Last Edit: November 26, 2011, 02:04:08 AM by JustDreaming »
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akcom

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Re: isomerization by base + PTC
« Reply #6 on: November 27, 2011, 10:17:44 PM »
Just to clarify its molecular chlorine (Cl2) not chloride ions which are thought to be responsible for the degradation of LSD in tap water

Sedit

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Re: isomerization by base + PTC
« Reply #7 on: November 28, 2011, 06:12:11 AM »
Yes but can Cl2 even truely exist in an (Aq) solution? Is should form HCl and HOCl on contact with water the later which I would think should cause havoc on most organic substances let alone something as unstable as LSD.
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Assyl Fartrate

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Re: isomerization by base + PTC
« Reply #8 on: November 28, 2011, 12:31:36 PM »
Cl2 can exist dissolved in aqueous solution but you are right, much will convert into HCl and HOCl. Solutions of Cl2 will still be yellowish green from the dissolved chlorine. These days most tap water seems to have chloramine, which unfortunately does not go away on boiling. Ugh. Get distilled water...
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aniracetam

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Re: isomerization by base + PTC
« Reply #9 on: November 29, 2011, 12:18:52 AM »
a brita filter would likely suffice.

or get distilled water if you're really that paranoid, but it may  be more helpful to find some data on the matter rather than pondering over anecdotal hypotheses.
« Last Edit: November 29, 2011, 12:30:34 AM by aniracetam »
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Vesp

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Re: isomerization by base + PTC
« Reply #10 on: November 29, 2011, 12:39:58 AM »
Distilled water is like $0.50 a gallon. Might as well just use that anyways. Not like it is a big financial decision. Just pick it up next time you go to the store or whatever.
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aniracetam

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Re: isomerization by base + PTC
« Reply #11 on: November 29, 2011, 12:44:29 AM »
no, i don't wanna..
0.4 um filter + ion exchange/ac = win.
if I need distilled, i'd just rv it.
« Last Edit: November 29, 2011, 12:46:27 AM by aniracetam »
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akcom

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Re: isomerization by base + PTC
« Reply #12 on: November 30, 2011, 06:32:40 AM »
Quote from: Sedit on November 28, 2011, 06:12:11 AM
Yes but can Cl2 even truely exist in an (Aq) solution? Is should form HCl and HOCl on contact with water the later which I would think should cause havoc on most organic substances let alone something as unstable as LSD.
It's an equilibrium that greatly favors aqueous chlorine over HOCl and HCl
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