P2P Oxime Questions

[Xicori]

High Bees!

Swim wanted to try oxime formation with the ketone produced in

Post 478384

(Xicori: "P2P from Aniline!  (Meerwein arylation)", Methods Discourse).

Sonson´s procedure (Chromics variation) was used.

https://www.thevespiary.org/rhodium/Rhodium/chemistry/alhg.oxime.html

To a 100ml RBF was added 2,7g of waterfree Sodium acetate and 9ml of water. Then 2,6g NH₂OH.HCl (~37mmol) was added and the mixture was stirred until most solids were in solution.

To this solution was added 4g (~30mmol) of P2P in 22,5ml of MeOH and the resulting yellow solution (still some solids undissolved) was refluxed for 90min. Even at reflux temperature some solids didnt dissolve.

After the mixture had cooled to room temperature 25ml of water was added and the mixture was put into the freezer but nothing crytallized - only some yellow oil fell out to the bottom of the flask.

So the mixture was extracted with 2*40ml Ethyl acetate. The cobined organic phases were dried over Na₂SO₄, and the solvent was removed on the rotary evaporator to leave ~5g of a yellow oil that does not want to crytallize in the freezer.

Now the questions:

SWIm coundnt find physical properties of P2P-Oxime on TFSE (only about MDP2P-oxime and methoxy-substituted oximes - they were all solids).

So it made swim wonder that his product was an oil. - Does anybee know the physical properties of P2P-Oxime or a good way of testing the product?

TLC? - any recommendations on the eluant?

Best wishes and a happy and productive year 2004!!  

xicori

[Rhodium]

P2P oxime is discussed as "benzyl methyl ketoxime" in

Post 402025

(Rhodium: "Ye olde Benzedrine", Stimulants)

[Xicori]

High!

Thanks Rhodium! - but in these procedure there is no yield given, but i think a yield of 90%+ should be possible...

SWIM made a TLC on his suspected oxime, but swim doesnt know what to think about the results...

Eluent was 1:1 Ethyl acetate : Pet Ether

Ketone (as reference sample): 1 single spot Rf = 0,87

Oxime: one little spot with Rf = 0,32, and one larger spot Rf=0,79

Is the Rf-difference between 0,79 and 0,87 big enough to say that these are different substances?

What could be the second spot at Rf = 0,32 ??

The product still didnt crystallize, but became very viscous.

Thanks for the help,
xicori

[hypo]

well, you should get syn- and anti-oxime. but i doubt this
can explain such a huge difference.

> Is the Rf-difference between 0,79 and 0,87 big enough to say
> that these are different substances?

how about mixing ketone and suspected oxime and see if it resolves
into 2 different spots?

you probably know it, but just in case, this procedure claims 100%:

Post 319296

(Rhodium: "P2P oxime in quantitative yield", Novel Discourse)

[armageddon]

Hi!

As your suspected oxime didn't cystallize even after isolation and separated to the bottom - maybe it is unreacted ketone? Oxime oiling out normally floats to the top AFAIK, perhaps someone could dig out the phys. properties (esp. density) of P2P oxime, I would guess its lighter than water?

The properties known to me are:

-melts at 70°C

-clear, off-white oil with a distinct aromatic smell

-crystallizes slowly upon freezing, giving crunchy, clear/colorless crystals

-mw 149.189 g/mol

-soluble in ethyl acetate, toluene, alcohols (also sparingly soluble in water? dunno..)

That's all I know about it.


Greetz A

[armageddon]

Hm, seems I wrote bullshit in my above post (sorry for that): the reason why I believed that P2P oxime would have a density >1 was that in a saturated salt solution, the oxime oils out and floats to the top - but of course this is due to the higher density of saturated salt solutions. P2P oxime is lighter than water...

(the other properties are right so far - does anybody know about the density of P2P-oxime?)

Greetz A