12-14-03 19:33
No 476893
SWIM really wants to do this....
Phenylalanine solution treated with hypochlorite solution, extracted and directly refluxed with methylamine until no more water is generated, purify my ketone and be happy with the ease, SWIM really wants to get around the benzene altogether, what can be done. There isn't mych on this type of reaction in TFSE at all, I'm thinking the benzene can be replaced in the oxidation but I'm not sure of the amination step.
--Word on the street is, You Reap What You Sow
(Hive Bee)
12-14-03 19:39
No 476895
You will not get P2P from hypochlorite oxidation of phenylalanine, you will get phenylacetaldehyde. There is however synths of meth from this too, look at rhodiums site.
(Hive Bee)
12-14-03 19:46
No 476897
Ahem, that is the meaning, please re-read my post, I am talking of oxidation to phenylacetaldehyde then amination to P2P with methylamine, I should have been more specific about the ketone, sorry.
--Word on the street is, You Reap What You Sow
(Hive Bee)
12-14-03 19:59
No 476901
Ahem, wouldn't amination of phenylacetaldehyde with methylamine yield N-methylphenethylamine? Or are you proposing that the imine between phenylacetaldehyde and methylamine will rearange into P2P?
Please elaborate on how you will get phenylacetone from phenylacetaldehyde and methylamine.
(Hive Bee)
12-14-03 20:04
No 476902
Maybe amination isn't the word for it, actually I don't know what the hell you would call it, but It isn't something I came up with on my own josef, so stop being an asshole, and be hospitible.
../rhodium/meth.phe
--Word on the street is, You Reap What You Sow
(Hive Bee)
12-14-03 20:08
No 476904
Ok, sorry. Actually it was precisely that method I was meaning earlier in the thread. But when you said that the product you were expecting to get was P2P you made me wonder.
Edit: And to answer your question, it's likely that you can replace the benzene with toluene in the last reaction.
(Hive Bee)
12-14-03 23:16
No 476937
1b) (alternative) JACS 70, 3868 (1948)
Distill methylamine gas (prepared by dripping 50% NaOH in water over methylamine hydrochloride crystals) onto cooled phenylacetaldehyde (45.7 g, 0.38 mole) while stirring until the solution has gained about 15 g (0.5 mole) of methylamine. Let stand for 1-2 hrs under cooling and stirring. Extract the mixture with dry ether, dry the ether and evaporate the solvent to get about 80-90% yield of aldimine. With the aldimine in hand, it's important to proceed directly to the next step: the preparation of a methyl Grignard solution in ether.
Well, this suggests that you can just bubble some MeAm gas through phenylacetaldehyde without solvent, so then this can be done at RT, cool in ice bath with stirring and then extract with solvent, hopefully something other than ether.
I am assuming the P2P has a short shelf life since this says the aldimine should be used directly after making it.
I can't beleive I overlooked that part, does any one have any advice with this?
Game Plan
Treat an aqueous solution of 20g of l-phenylalanine in 500ml water with an aqueous 0.3N solution of sodium hypochlorite in 300ml water. I am shady on this part since this is where SWIM is suposed to solvent extract the aqueous layer. Anyway, take the resulting aldehyde and hook up to a gassing advice, take freshly prepared methylamine and create the gas with a solution of NaOH, probably an eye dropper, beer bottle, tubing, and rubber stopper will be used to gas, all the while measuring on a gram scale to make sure the solution gains 5g and then cool with stirring and proceed to reduction of choice, how does this sound, incomprehensible, unrealistic, shady, input please.
--Word on the street is, You Reap What You Sow
(Hive Bee)
12-15-03 14:36
No 477074
Ok, I still don't quite get all of this, so I will try to gain a better understanding through true/false Q&A....
Reacting phenylacetaldehyde with methylamine gives p2p.
True or False?
The reaction product of phenylacetaldehyde and MeAm will react w/ leukart to give meth.
True or False?
Their is an easy procedure to get p2p from phenylacetaldehyde.
True or False?
I have read the way of getting the p2p from cadmium, and I read that reaction product between phenylacetaldehyde and MeAm will react with MeMGBr to give meth without going through p2p
--Word on the street is, You Reap What You Sow
(Hive Bee)
12-15-03 18:15
No 477110
The two first statements are false.
As you have obviously read the cadmium procedure to make phenylacetone from phenylacetaldehyde I think you can judge for yourself the third statement.
Personally I would choose the last method you list, react the imine between phenylacetaldehyde and methylamine with MeMgI, to get meth. (If you choose the cadmium route you anyway have to prepare MeMgI and then turn that into Me2Cd, and after that get phenylacetone. And then turn that into meth by some route. More work...)
(Hive Bee)
12-15-03 18:22
No 477111
Does it still produce the racemic mix almost identical to p2p meth, that is what SWIM is going for and just started dippin his toes into this P2P PPA this and that stuff.
All in all, I guess that the MeMgI will be almost as easy to prepare as n-methyl-formamide, I really hate all this carcinogenic stuff and ether is one of the nastiest fuming bitches of a solvent one can use IMO. Thanks josef
--Word on the street is, You Reap What You Sow
(Hive Bee)
12-15-03 18:25
No 477113
Yep, it will produce the racemic meth.