05-23-02 02:33
No 313044
In the synth of p-meo phenol from hydroquinone & benzoquinone found by our Siberian clan chem warrior Antoncho (Patent GB1557237), can one use the appropriate quantity of quinhydrone (hydroquinone-benzoquinone complex) as a substitute for benzoquinone ?
In Post 268566 (Antoncho: "Re: P-MeO-phenol from hydroquinone: part II", Novel Discourse) Antoncho suggested that quinhydrone is formed initially anyway.
(Hive Bee)
05-23-02 17:19
No 313364
I tried once to do the Spiceboy synthesis of p-benzo using quinhydrone instead of hydroquinone, it did not work. I assume you will need to start from hydroquinone ( or p-benzo in your case ). I am not sure about the reaction you mentioned, but I am afraid the intermediate steps of the synthesis will not go the right path. I would suggest you get or make p-benzo instead. Making it is better than buying it, p-benzo is suspicious, watched. I would suggest also cleaning the green p-benzo with DCM, I so far have had good results. If you want more info see my previous thread on "p-benzo making". I would also add one extra wash ( before DCM distill off ) with cold water.
(Official Hive Translator)
05-23-02 21:04
No 313437
Yeah, of course, quinhydrone will work just fine!
It IS formed immediately upon contact of BQ w/HQ (black precipitate), but then gradually dissolves.
Another thing is that SWIM was never able to get the yields stated in the patent, they're always significantly lower
. So maybee it'd bee a good idea to twitch this rxn somewhat or use the 'reflux' variation instead of RT one.Antoncho
P.S. Siberian clan chem warrior -
LOL, that's one nice epitet! Thanx
(Hive Bee)
05-24-02 01:06
No 313516
Wolfx:
It seems that the lack of success with the Spiceboy synth shall remain a mystery. At a later stage I'll probably try one of the alternate methods (I wonder if ammonium dichromate could work...)
Antoncho:
I decided to go ahead and try it anyway. Rinsed the quinhydrone (resulting from the HQ/H2O2 synth) a few times with MeOH in which some of it seems to dissolve but so what. Added this to HQ/H2SO4 in MeOH and the mixture has been swirling for ~16 hrs at ~20°C as I type. The soln immediately went black as was your experience but has remained that way up until I last checked (4hrs ago). Closer inspection revealed that the soln is actually a very dark green. Tonite I may try the the reflux option and let you know the results on Mon.
Just for the record I wasn't ass-kissing with that epithet, I just genuinely think you are on the frontline in the WOD and some support and praise is deserved (Hive medals for bravery in action?)
Btw, any progress on 2cb?
(Official Hive Translator)
05-24-02 06:43
No 313619
The soln , in SWIM's dreams, has stayed very dark-green for some time, but after ~30 mins beecame trransparent and dark reddish-brown.
When SWIM tried using HMeSO4 instead of H2SO4 (like to keep it unhydrous), the color change happened much slower and the resulting soln was of much darker color then in the previous trials. Thus SWIM concluded that it's no improvement.
He didn't compare the yields, though - don't ask him why.
So.... Maybee all that's needed in your case is to hold it for some longer time. Do you, by chance, have TLC? It would bee an immense improvement - to see how the rxn goes and what happens; SWIM himself dearly wishes he had such a possibility, but, alas...
As for 2C-B, SWIM's own experiments has been stopped for the reasons of awful businesss, esp. lately, in connection w/our moving to the Hive
Just want to note - that OH-, orrto- to the aldehyde group, is very deactivated to electrophyllic substitution, - at least in 4 trials of both SWIM and SWIVitsh w/MeI, a satisfactory yield wasn't reached. Vitsh was the most successful at that - he managed to get the aldehyde, but there , again, seems to bee smth fishy w/that cold condensation method (wrong mp, possibly the nitroalcohol).
OTOH, DMS seems to bee the way to go, according to Karl's experience.
Well, one day when we'll come (hopefully) to some conclusive modus operandi, i'll make a complete report. Not now.
Best Wishes,
Antoncho
(Hive Bee)
05-28-02 03:11
No 315122
First result of p-methoxy phenol-using-quinhydrone trial:
After being stirred and maintained at ~ 40-45°C for um I dunno, about 12 hrs or something, the mixture was still a dark green, but there was a fair amount of a crystalline ppte. More ppte resulted as the soln cooled. I tried an extraction with xylene. The solid did not dissolve in xylene. Also, the xylene remained clear (no color taken up). So I separated the xylene layer and then filtered off the crystals. While the crystals were suspended in soln, they appeared as white or beige needles. After filtration, they look pea green, probably due to some impurity. These crystals seem reasonably soluble in water and MeOH. What is this stuff ?
Thoughts:
-The crystals may simply be unreacted HQ (also white needles). However when the reaction mixture was first made up, the HQ dissolved quickly and completely. Therefore if it is HQ it should still be mostly dissolved, even though some MeOH evaporated off during the reaction.
-I have hoped against hope that the crystals may be the desired p-methoxy phenol which would be acidic and would therefore ppte out of an acidic soln, but its apparent insolubility in xylene suggests otherwise.
-I will now try to recrystallize (I'm sure yet what solvent to use), dry and check the mp.
Any ideasss....beeeezzz..?
Antoncho,
Just want to note - that OH-, orrto- to the aldehyde group, is very deactivated to electrophyllic substitution, - at least in 4 trials of both SWIM and SWIVitsh w/MeI, a satisfactory yield wasn't reached. Vitsh was the most successful at that - he managed to get the aldehyde, but there , again, seems to bee smth fishy w/that cold condensation method (wrong mp, possibly the nitroalcohol).
I was under the impression that Vitsh (or his grandmothers dog's ghost or something - I forget) had successfully gone as far as the nitropropene ? Did I get my facts fucked ?
(Hive Bee)
07-19-02 03:26
No 334545
Finally some new results using quinhydrone (QH):
Expt 1
As detailed in above post, using wet impure QH, etc.
Result__> crap
Expt 2
Similarly to 1, same wet impure QH etc., but then a whole lot of nasty personal stuff happened blah, blah
Result__> inconclusive but probably crap
Expt 3
10g HQ + 2g QH(recrystallized from MeOH/H2O and dried in dessicator with H2SO4, crystals actually dark red brown but reflect green) + 12ml 95% H2SO4, all in 45ml MeOH.
Refluxed 5 hrs. Mixture was transparent dark reddish brown from the begining. Added 45 ml H2O. Distilled off most of the MeOH. Extracted with xylene (1x30ml,1x20ml). Evaporated xylene in vacuum.
Result __> ~9.9g of chocolate looking solid. Melts with some warming. The mp of p-meo-phenol is ~52°C so this is an encouraging sign.
Recrystallization trials: Tried DCM, acetone & 'lacquer thinners' (which I suspect to be MEK cos it ain't toluene)
None satisfactory. Acetone looked best but it leaves a crystalline sludge (rather than a slurry) not easily filterable. Maybe acetone/H2O will work (add water to chocolate (wait isn't that a movie?), add warm acetone until all dissolved, evap acetone under weak vacuum so that bp < 52°C) ?
Anyhow, these trials eventually destroyed the product.
Expt 4
34.4g HQ + 6.9g QH(dry, recrystallized from MeOH/H2O) + 22ml 98% H2SO4, all in 145ml MeOH.
Refluxed 5 hrs. Mixture was transparent dark reddish brown from the begining as before. Realized didn't have enough extraction solvent, so had to distill some DCM from paint stripper. Mixture was stirred at about 30 °C in the meantime (~ 2.5 hrs).
Added 100 ml H2O. Distilled off ~ 100ml MeOH.
(After ~75ml distilled, a black oil started separating)
About 40ml of floating black oil afterwards.
Left overnight which was quite cold (maybe 5°C). Mext morning there was a white crystalline ppte in water phase, probably unreacted HQ. Extracted with DCM (1x80ml,1x60ml,1x20ml). Ppte dissappears. Evaporated DCM, leaving ~ 35 ml black (v. dark brown) oil. Solidifies on cooling.
Result __> ~34g of chocolate looking solid. Melts when warmed.
Notes:
- Either the use of decent QH or refluxing seemed to make a significant improvement.
- Added less H2O in 4 than 3 hence the appearance of oil when distilling MeOH off.
- Would extract with less DCM next time (eg. 1x80ml,1x50ml)
- Couldn't measure mass of crude product (scale limited). Estimate of 34g based on vol of oil before solidification. Therefore not sure about yield & purity.
-Not going to bother with recrystallization again. Will use crude product in next reaction (R-T formylation to aldehyde using new patent found by Antoncho, Post 330714 (Antoncho: "A patented improvement", Chemistry Discourse))