PNP's into amphetamines reduction on alu foil

IndoleAmine · Dreamreader Deluxe

Oh, and brain: try using SnCl2 dihydrate, 2.1x molar excess to (substituted) phenyl-2nitropropene - suspend the SnCl2 in EtOAc, stir to dissolve as much as possible, then slowly add the nitropropene in small amounts while stirring, the temperature of the solution shouldn't rise above 30°C (addition may take a while; please be patient here!). If it gets too hot, use an ice/water bath to cool to below 30°C.
After all P2NP has been added, stir for 30 minutes, until the color doesn't change anymore (it is yellow, but becomes almost white at the end). Now add 8x molar excess of HCl as 20% aequous solution, remove the EtOAc using aspirator vacuum, then reflux the whole thing for 1 hour, and steam distill the P2P (or extract with DCM when working with substituted nitropropenes, as they often cannot be steam distilled). Yield is 70-80% of theory.
(procedure courtesy of Barium - was just too lazy to look it up, but its in the hive archives somewhere...)

i_a

brain · Linguist Extraordinaire

hm, p2np reduction thes way Smile

in progress

like in post before! he reaction wa so vigorous - it was boiling ! when cooled down, with colt water bart-it didnt boilet agan... but was wery hot!

now will let it cool for couple of minutes, ad NaOH solution, and chec it Smile

extract with ethyl ether.

IndoleAmine · Dreamreader Deluxe

Cool - I own exactly the same beaker like you have, even the same size.... Laughing

(and I LOVE pictures! Hope we'll see more of them!?)

Good work!!

i_a

brain · Linguist Extraordinaire

when the mixture is acidic Ph

when the ph is rised (adding NaOH solution)

2 layers had separatet-white&gray (containing Hg !)

extracted with ethyl ether

and -shock !! i feeld bad-because the ether wac colorless!! but when ether evaporatet the colorless oil have formed !!

tested on tlc's

and its almoust pure amphetamine freebase! with 1,4% p2p and some impurytis [less than 0,4%- b.p tested, tlc]

with 79% yeld (about 16g)

brain · Linguist Extraordinaire

i couldnt wait till tomorrow Smile

and take 1/10 of oil ! soluble in acotone ! take H2SO4 [98%] add to it acotone [the actone+h2so4 after 20 min is reacting->red liquid, hawe to be prepared before makin amph*sulphate]
and ad to amph+acetone... white precipate have formed !! total white !

the filtrate was threated h2so4... and precipate filtred.. [3x was propered!!]

--- the last adding of h2so4-the crystals formed-and imidietly soluble... next 5 min-the pink solub was formed !! [impurytis??]

IndoleAmine · Dreamreader Deluxe

Thumbs up (not for your english; but for the pics Laughing

)!!

About making the sulfate, normally it goes like:

- Dissolve amph freebase in 4x its volume of MeOH, EtOH or IPA
- dissolve calculated amount of H2SO4 in roughly same amnt. of alcohol
- add H2SO4 soln. slowly to amine solution with good stirring, don't add everything at once
- everytime the thing gets thick from precipitated sulfate (making a paste), you filter off the sulfate salt and rinse the filter cake with acetone
- you can't get all salt when making the sulfate, the last 5-10% will always redissolve and form red/pink amine hydrosulfate which is waaaay more soluble than diamine sulfate...

(keep a bit of freebase amine in the beginning; then just add 80% of the H2SO4 soln. slowly, then filter off sulfate, then add more H2SO4 dropwise until sulfate starts to dissolve again, then add a few drops of amine and filter the remaining sulfate. Thats how I would do it)

greets

i_a

brain · Linguist Extraordinaire

i will do this with rest of amph.freebase Wink

-can i use EtOH instead IAP -in the Al/Hg reduction proces?

IndoleAmine · Dreamreader Deluxe

I have used them both with Al/Hg, it works - but this wasn't with nitropropenes but with ketones.

Nevertheless it should work too: both EtOH and IPA can't mix very well with satd. hydroxide or salt solutions and separate to the top (tIPA/EtOH are less polar than these satd. solns.), and both can dissolve p2np, and its oxime and the amine too, andboth are miscible with water, so they should both work...

i_a

tetraedr · Sun Mar 27, 2005 1:08 am

I think, here is no big difference between MeOH, EtOH and i-PrOH.

But the main problem here - the filtration of sulfate salt. SWIM did this reactiom one time and had a strong problem with it. He has got about 3 g of freebase (mabe not so dry from the rest of solvent), but only 1.5 g of salt from it. I think, he lost a lot of substance during washing the filter.

I think, maybe better to evaporate thoroughly the white paste after acidifying and then dry the precipitate in the oven (at 50-60 grad).

brain · Linguist Extraordinaire

no ! it will smell-bad .... it have to be washed - after filtrating... then it is white-and dont smell Smile

IndoleAmine · Dreamreader Deluxe

tetraedr: Probably because the fb wasn't dry? You have to rinse the filter cake with (dry) acetone before drying it, this removes impurities and water. And these are both reasons why your sulfate did disappear in the filter: it wasn't waterfree, and since sulfates love water, it probably dissolved in the tiny amnt. of water you had present, and this water/sulfate solution was taken up by the filter paper, or dissolved in solvent you used...

Drying the salt in an oven is a good idea, but only when the sulfate was washed very thoroughly with acetone and/or alcohol, since the impurities will else make your sulfate become dirty and yellow-looking. Only ultra-clean sulfate is suitable for oven drying.
(like brain said)

And MeOH is good for making the sulfate; but for Al/Hg it is crap deluxe! You can't separate any phases, and have to add a whole lot of water and toluene/ether/whatever, a very messy thing and not recommended. Use IPA or EtOH for Al/Hg, they aren't very miscible with conc. lye solutions and form a top layer which is much, much easier to xtract than MeOH/hydroxide mess.....

i_a

icecool · Insistent Chemist

First off all brain very nice pics they also help to clarify people things when reading a lot who never did such a reaction...
And second off all, SWIM is thinking about insted of doing a THF+LiAlH4+P2NP reduction.
Insted of that doing the Al/Hg reaction.
SWIM thought about this procedure can anyone confirm this and answer the questions... Smile

To a 10,37 g of thin aluminium foil cut in 1 inch squares (in a 2 L glass) there was added 650 ml of warm (not a cool) water and 65 mg of mercuric chloride. Amalgamation was allowed to proceed until there was the evolution of the fine bubbles, the formation of the light-grey precipitate and the appearance of the occasional silvery spots on the surface of the aluminium. It takes about 10-15 min, depending on the freshness of surface and temperature of the water. The water was removed by decantation and foil was washed twice of water. Then to glass was added 40 mL of water followed by the hot solution of phenyl-2-nitropropene (7 g, 0,26 mol) in the mixture of 52 mL of IPA and 26 mL of AcOH Then the exothermic reaction was occurred, mixtures was become to reflux (cooling is not necessary), but strong mix by stick is strongly recommended. Aluminium foil was dissolved into the grey precipitate. Reaction was complete after 15-20 min. Mixture was cooled down, diluted with 200 mL of cool water, alkalized with KOH solution until strong base, the product was extracted with ether (3x50), combined organic layers were washed with water, dried over sodium sulfate and thoroughly concentrated under vacuum.

Is it necesarry that KOH is used can also NaOH be used?
Can magnesiumsulfate also be used?
Concentrated under vacuum....can't you just let the solvent evaporate at roomtemperature...or should one distill the oil?
IF you are going to heat it to get rid of the solvent does it need to be under vacuum? Since brain IIRC let the solvent evaporate on roomtemp and if I am right tetraeder did too?
And isn't this a lot easier than LiAlH4 in dry THF or ether.
Since here you don't have the problem of a water sensetive mixture (explosive) while the reduction finds place, and there also isn't the costs of moleculair sieves...
Anyway what will be the expected yield from 7g of P2NP, like 5,5g or so of amphetamine freebase?

SWIM used tetraeder's method BTW and adjusted the amounts for SWIM's amount of P2NP...

And what about this method to prepare Aluminium amalgam?

IndoleAmine · Dreamreader Deluxe

Just in case you all havent grasped it yet: Hg is damn deadly toxic, is liquid, has a very low vapor pressure and will evaporate when heated. (!)

Even if you distill plain water and the flask you are heating contains elemental Hg, some of the Hg will distill over together with the water, at a rate of about 10-20mg/500ml!!!! Exclamation

Also, the problem with mercury is not that of one single exposure, it is more that of a long term exposure: the Hg vapors contaminate the room and you breathe trace amounts of Hg all the time while at work. Mercury accumulates in the human body, since it can only be excreted slowly in very small amnts. through the urine. And I don't want to explain a mercury poisoning resulting from chronic exposure here in detail, you can look that up for yourself if you want to know what happens to you when working with Hg. One last thing: for keeping the effective concentration of Hg vapor low enough to maintain safe working conditions, the air has to be replaced AT LEAST 6-8 times per hour, so you should work with very good ventilation! Also note that Hg vapors are without any smell, you only notice a slight headache maybe - but as said, the danger lies in the long-term exposure and resulting accumulation, leading to sudden toxic symptoms, which include shakiness, personality disorders, tremors, manic behavior and severe shizophrenia as well as bleeding teeth, dark borders visible above the teeth, teeth falling out, and finally death.

You have been warned! Always make sure all windows are opened, no open rxn vessel if possible, don't bend over the beaker while stirring, you would breathe a lot of toxic Hg vapor. And please, please, please WASH you freebase VERY thoroughly with lots of satd. NaCl solution, if possible distill the freebase before forming any salt.

Its a pity that Al/Hg is such a nice reducing agent, though with such an enormous toxicity......

i_a

IndoleAmine · Dreamreader Deluxe

Hmm - LiAlH4/THF is very easy too, and surely less toxic to work with than the by-product of an Al/Hg - elemental mercury....

Yes, NaOH can be used to basify, just as well as KOH - just bring the pH up to above 12 with any tool you have at hand (even ammonia or bicarb, but it foams like hell)... Wink

Evaporating the solvent is sometimes ok if you use ether or something similar low-boiling, if you own a fumehood and have plenty of this particular solvent anyway; because high-boiling solvents like toluene would evaporate too slowly, and the amine evaps/disappears completely before the solvent has evapped. Also, the solvent that evaporates presents a fire hazard as well as a health hazard, and "detection hazard" too maybe. And it is lost forever, plus it needs a lot of time to evaporate solvents without heating.

And some amines react with the CO2 in the air to form carbonates (2C-H for example), another reason to use vac distillation for solvent removal.

Recover the solvent at least with normal distillation if you have the apparatus, then evap the last solvent traces at room temp.

You do nobody a favor when evaporating unhealthy hydrocarbons without any need, neither good for your busget nor for your environment - so recover solvents always if possible, this is good lab practice and should really be followed.

i_a

brain · Linguist Extraordinaire

but-Al is cheaper Very Happy

than LAH

and i dont like working with thf...