Rhodium (Chief Bee)
02-04-01 19:26
No 171132
      New ways of making 2C-B  Bookmark   



How about this? I have references for most of the steps if desired, but I'll only dig them up if somebody is going to try it out [ Lazy ].

 
 
 
 
    foxy2
(Hive Addict)
02-05-01 20:14
No 171275
      Re: New ways of making 2C-B  Bookmark   

Hey Rhod
Your pic is not working.


Do Your Part To Win The War
 
 
 
 
    Rhodium
(Chief Bee)
02-06-01 00:26
No 171312
      Re: New ways of making 2C-B  Bookmark   

The pic-proxy must be down, because the image really is there. Check http://rhodium.lycaeum.org/2cb.gif


http://rhodium.lycaeum.org
 
 
 
 
    Alphabeta121
(Hive Bee)
02-06-01 06:35
No 171363
      Re: New ways of making 2C-B  Bookmark   

rhod I was looking at it and it seems the only reagent thats pretty tricky to get are the acetyl ...  and those can be made w/ sulfur and bromine and sodium acetate.  What is the mechanism on that reaction and is the best way of getting bromine still oxidation of KBr via H202?
 
 
 
 
    Rhodium
(Chief Bee)
02-06-01 09:23
No 171384
      Re: New ways of making 2C-B  Bookmark   

I believe that the bromine and sulfur forms a sulfur bromide, which in turn reacts with the sodium acetate, forming acetyl bromide and sodium bromide.
Yes, if you cannot aquire bromine in its pure state, I believe that the oxidation you are talking about would be the best option.


http://rhodium.lycaeum.org
 
 
 
 
    Alphabeta121
(Hive Bee)
02-08-01 05:23
No 171570
      Re: New ways of making 2C-B  Bookmark   

hey rhodium, are you sure the Pd/C reduction would occur w/ formate?

alphabeta121
 
 
 
 
    Rhodium
(Chief Bee)
02-08-01 16:48
No 171622
      Re: New ways of making 2C-B  Bookmark   

I have seen he following work in papers:

Pd/C and H2 gas => reduction of phenyl alkyl diketo monoximes
Pd/C and formate => reduction of phenyl alkyl ketones
Pd/C and formate => reductions of oximes

I haven't seen this particular reduction though, but as all of the above works, I see no reason that what I outlined above wouldn't work.


http://rhodium.lycaeum.org
 
 
 
 
    obituary
(Hive Addict)
02-09-01 05:37
No 171692
      Re: New ways of making 2C-B  Bookmark   

would you mind posting a procedure with some ratios? 
(refering to both Rhodium and Iudexk)
 
 
 
 
    Rhodium
(Chief Bee)
02-09-01 17:48
No 171766
      Re: New ways of making 2C-B  Bookmark   

2,5-dimethoxyacetophenone from 1,4-dimethoxybenzene: http://www.erowid.org/library/books_online/pihkal/pihkal024.shtml

Isopropyl nitrite from IPA/NaNO2: http://rhodium.lycaeum.org/chemistry/drone/isopropylnitrite.html

Methylation of hydroquinones: http://www.erowid.org/library/books_online/pihkal/pihkal023.shtml

Bromination of 2C-H: http://www.erowid.org/library/books_online/pihkal/pihkal020.shtml

Catalytic transfer hydrogenation: http://rhodium.lycaeum.org/chemistry/cth.txt


Hydroquinone diacetate [1]

Add 1 drop of concentrated sulphuric acid to a mixture of 55 g (0.5 mol) of hydroquinone and 102 g (95 ml, 1 mol) of acetic anhydride in a 500-ml conical flask. Stir the mixture gently by hand; it warms up rapidly and the hydroquinone dissolves. After 5 minutes, pour the clear solution on to 400 ml of crushed ice, filter with suction and wash with 500 ml of water. Recrystallise the solid from 50% aqueous ethanol (ca 400 ml are required). The yield of pure hydroquinone diacetate, mp 122°C, is 89 g (91%).

2,5-Dihydroxyacetophenone [1]

Finely powder a mixture of 40g (0.2 mol) of dry hydroquinone diacetate and 87g (0.65 mol) of anhydrous aluminium chloride in a glass mortar and introduce it into a 500ml round-bottomed flask, fitted with an air condenser protected by a calcium chloride tube and connected to a gas absorption trap. Immerse the flask in an oil bath and heat slowly so that the temperature reaches 110-120°C at the end of about 30 minutes: the evolution of hydrogen chloride then begins. Raise the temperature slowly to 160-165°C and maintain this temperature for 3 hours. Remove the flask from the oil bath and allow to cool. Add 280 g of crushed ice followed by 20 ml of concentrated hydrochloric acid in order to decompose the excess of aluminium chloride. Filter the resulting solid with suction and wash it with two 80 ml portions of cold water. Recrystallise the crude product from 200 ml of 95 per cent ethanol. The yield of pure 2,5-dihydroxyacetophenone, mp 202-203°C, is 23 g (58%).

Edit: Another prep if the above is Post 389647 (demorol: "2,5-dihydroxyacetophenone synthesis", Methods Discourse)
 
 
 
 
    RollWitMe
(Newbee)
02-14-01 18:04
No 173301
      Re: New ways of making 2C-B  Bookmark   

I have adequate Pd metal , power supplies and most chemicals needed to plate Pd. Just curious if anyone has plated Pd on activated carbon. I have done it w/ Pt using Hexachloroplatinic acid plating solution but am not experienced w/ making up a Pd plating bath. Anyone know of a good web site/link to lead the way? Thanks. Also anyone know where I could sell 9 oz Pd metal without turning heads?


I like to cook!
 
 
 
 
    foxy2
(Hive Addict)
02-14-01 21:26
No 173332
      Re: New ways of making 2C-B  Bookmark   

At a precious metal dealer FUCKWitMe
Not HERE!!!!!


Do Your Part To Win The War
 
 
 
 
    zooligan
(Hive Addict)
02-16-01 15:27
No 173705
      Re: New ways of making 2C-B  Bookmark   

The only way Pd metal would turn a head at all would be if it was somehow associated with drug synthesis.  In any other circumstance, Pd is completely innocuous and unwatched, like gold, silver, pork bellies, corn syrup, or any other commodity.
 
 
 
 
    terbium
(Hive Addict)
02-16-01 20:00
No 173749
      Re: New ways of making 2C-B  Bookmark   


The only way Pd metal would turn a head at all would be if it was somehow associated with drug synthesis


Or if a local metal plating company had recently reported the theft of 9 oz. of palladium.

 
 
 
 
    RollWitMe
(Newbee)
02-19-01 06:56
No 174235
      Re: New ways of making 2C-B  Bookmark   

Let me go down to the local precious metal dealers cause there's one on every corner just like Starbucks right you moron? Wrong, I figured on trying out a jewelers, and no these were not the victums of theft. SWIM has made an adequate amount of PdCl2 from it and figures he can sell them. I love how you try to make me look dumb and answer the easier of the 2 questions I asked. The main thing I want to know is if anyone knows a web site or procedure for making up a Pd plating bath. I know for most other precious metal plating baths, you have an acid/cyanide and even arsenic for plating gold. I really don't feel like jacking with cyanide ever again. I worked w/ a cyanide plating line for 6 months and it's not a pretty site. That's what is nice about platinum over gold, no cyanide involved, btw, would Pt/C be an adequate substitution for the reduction instead of Pd/C . If so that answers my question because I do have Pt/C . Thanks in advance.


I like to cook!
 
 
 
 
    Alphabeta121
(Hive Bee)
02-19-01 19:41
No 174325
      Re: New ways of making 2C-B  Bookmark   

Rhodium would you mind explaining the mechanism between the reaction of isopropyl nitrite and the aldehyde?  and the name of the rxn product?

alphabeta121
 
 
 
 
    Rhodium
(Chief Bee)
02-19-01 21:52
No 174341
      Re: New ways of making 2C-B  Bookmark   

For a reference to that reaction, see JMC 34, 1662-1668 (1991), where an indanone (which is another phenyl alkyl ketone) is reacted with isoamylnitrite to give the alpha-oxime ketone.

"Indanone 18 (12g, 68 mmol) was dissolved in 375 ml of MeOH and heated to 45°C. Isoamylnitrite (10 ml, 75 mmol) was added, and then 7ml of conc HCl was added dropwise over 5 minutes. After 20 minutes of stirring, an off-white precipitate began to form. Excess isoamylnitrite and HCl (1 ml of each) were added after 45 min of stirring. The precipitated product was collected by filtration and washed with cold methanol and then ether (100ml). The filtrate was concentrated in vacuo and the residue recrystallized from MeOH. The two crops were combined to give 13.6g (96.9%)"

The reason I used isopropylnitrite in the outline above was just because I had a synthesis of it at my page, and that everybody may not be able to procure isoamylnitrite.

Mechanism:

1) The alkyl nitrite reacts with H+ to form a nitrosonium ion: R-O-N=O + H+ => R-OH + NO+

2) The nitrosonium ion reacts with the alpha carbon of the (enol form of the) ketone: Ph-CO-CH3 + NO+ => Ph-CO-CH2-N=O + H+

3) The formed nitroso-ketone tautomerizes to the more stable oxime: Ph-CO-CH2-N=O => Ph-CO-CH=N-OH

The final product is an ethylbenzene with a carbonyl next to the aromatic ring (known to be reduced to CH2 by Pd/C) and with an oxime group at the end of the chain (also known to be reduced by Pd/C). 




http://rhodium.lycaeum.org
 
 
 
 
    Antoncho
(Official Hive Translator)
09-12-01 19:00
No 212581
      Re: New ways of making 2C-B
(Rated as: excellent)
 Bookmark   

Here’s a patent (US 5,041,669) that explicitly describes reduction of an alpha-oximinoketone to an amine w/Pd/C, namely, p-hydroxyacetophenone to tyramine. There’s a trick to it – H2SO4 is used to dehydrate in situ the aminoalcohol that is otherwise produced by this reduction. The overall yield is 64% from p-OH-acetophenone.

It should bee noted that they use DMF for nitrosation, whereas in Rhodium’s example MeOH is used. Why? They don’t explain – if MeOH could bee used it’d bee both cheaper & simpler.

The patent also mentions that Ni catalyst may bee used – for us, the poor ones (won’t it react w/10% H2SO4 in AcOH?). I wonder if activated Urushibara Ni will work well… They say activated Raney Ni reduces acetophenone some 17 times faster than ordinary R. Ni… – see the thread & the patent for details (US 3,997,478).



 To a 3-neck 2 L flask is added 2.2 moles of dry HCl to 1000 ml of dry dimethyl formamide (DMF). To the flask is then added 272 grams (2 moles) of p-hydroxyacetophenone all at once. Then, 296 ml grams (2.2 moles) of 90% tertiary butyl nitrite is added very slowly so as to maintain the reaction medium temperature at about 40.degree. C., which takes about 2 hours, after which the reaction medium is stirred for an additional 3 hours while maintaining the temperature at about 40.degree.-45.degree. C. The contents of the flask are then poured into one liter of ice and extracted three times with 200 ml of ethyl acetate. About 200 ml of the crude, dry ethyl acetate solution is then added with 10.5 grams of 5% palladium/carbon catalyst to a reaction medium solution made by combining 350 ml glacial acetic acid and 35 ml of concentrated sulfuric acid. The reaction mixture is then placed in one liter autoclave reactor and degassed 3 times with nitrogen gas, then 3 times with hydrogen gas, after which the reactor is pressurized to 100 psig with hydrogen gas and the reaction is monitored over a period of 7 hours. The reaction mixture from the reactor is then filtered to recover the catalyst, and the filtrate is concentrated to recover Tyramine.H.sub.2 SO.sub.4 in 64% yield.



With that said, Antoncho wants to ask a couple more Q’s from “those skilled in the art” – he knows he’s too curious, yes, yes, his curiosity has killed more than one catsmile – that’s fine, he knows how to cook’em…

1. Pray tell me, when preparing acetophenone, why should one bother himself w/AlCl3 and AcOCl? Why not use AcOH/polyphosphoric acid instead (see http://www.erowid.org/library/books_online/pihkal/pihkal061.shtml for a gen. procedure). I also refer everyone interested to ../rhodium/chemistry /2cb-new.txt, where Assholium claims he always had 85-90% yields in this rxn.
This way demethylation won’t represent a problem so one can start w/p-diMeObenzene, making things much easier for a kitchen chemist. And polyphosphoric acid, i believe, may bee had by removing water from H3PO4 in vacuum.

2. It is known that =O can bee reduced to –H w/Clemmensen “under vigorous conditions” – my txtbook says. What are those vigorous conditions? Is there a chance that Clemmensen red’n might work? Perhaps 1st doing it at RT so as not to cleave the iminic double bond and them finishing it at an elevated temp?

3. Can anyone post a detailed proc. for making polyphosphoric (temp, time, pressure?) Does anyone know of any other catalysts for these condensations?


Any input will bee greatly appreciated.

Antoncho
 
 
 
 
    PEYOTE
(Hive Bee)
09-12-01 19:11
No 212587
      Re: New ways of making 2C-B  Bookmark   

Instead of CH3COCl in step 2 of the picture (the right link would be ../rhodium/2cb.gif) can I use acetic anhydride? It should be similar to the acetyl chloride... and can be prepared in a easier way, can't it?

 
 
 
 
    Rhodium
(Chief Bee)
09-12-01 19:31
No 212597
      Re: New ways of making 2C-B  Bookmark   

1) Yes, there are many ways of making acetophenones, but using acetyl chloride or acetic anhydride is "standard" methods, that's why they are most often referred to, to avoid confusion. I am certain that the polyphosphoric acid   acetic acid method works, if you want to try it out.

2) The "vigorous" reaction conditions in a clemmensen reduction is to reflux the ketone in concentrated HCl with zinc powder (which will certainly cause demethylation).

3) Polyphosphoric acid is usually prepared by mixing phosphoric acid with P2O5 (phosphoric anhydride), and I believe the ecact prep has been discussed here before. Try a search.

Peyote: Yes, that would work, but that chemical is watched worldwide, while acetyl chloride isn't.


What I would want to know if a catalytic transfer hydrogenation (Pd/C with ammonium formate at standard pressure) would work for the hydroximinoketone, that it works with high hydrogen pressures is well known, but that requires special apparatus, while my suggested method does not. I hope somebody would care to try it out.
 
 
 
 
    Kinetic
(Hive Bee)
01-14-03 22:23
No 398203
      Bringing up old threads...  Bookmark   

On a similar subject, I'm interested in making an analogue of 2C-B, keeping the beta-ketone on the final product. I've never heard of anyone making or tasting beta-ketone 2C-B before, and I don't even know if it'll be active, but I've outlined a procedure I hope will work:

1. Monobrominate 1,4-dimethoxybenzene to 1-bromo-2,5-dimethoxybenzene. (OK I know this works).

2. Acylate using either chloroacetyl chloride and AlCl3 or chloroacetic acid and polyphosphoric acid to give 4-bromo-2,5-dimethoxyacetophenone.

3. Perform the Delepine reaction on the purified 4-bromo-2,5-dimethoxyacetophenone from step 2 to give a salt which can be purified by recrystallisation.

How does this sound? I suspect it will be easier to brominate 1,4-dimethoxybenzene than 1,4-dimethoxyacetophenone or 2-amino-1-(1,4-dimethoxyphenyl)ethan-1-one (i.e. beta-keto 2C-H), which is why I proposed it this way around. I know AlCl3 may cause some demethylation in the second step, but Shulgin manages ~90% yield acylating dimethoxybenzene with propionyl chloride and AlCl3 so there shouldn't be a problem. I would try the AlCl3 procedure before using polyphosphoric acid since I already have some AlCl3.
Finally, the Delepine reaction on the primary alkyl chloride: I must admit I haven't done much studying on this reaction, but does anyone have reason to believe it wouldn't work, or would give terrible yields? From what I've read it should be happy on most primary alkyl halides. Any other comments? (Such as 'I tried beta-keto 2C-B and it was crap' would be disappointing but helpful).
 
 
 
 
    Vitus_Verdegast
(Stranger)
03-03-03 20:31
No 413385
      polyphosphoric acid  Bookmark   

A while ago I was in the hardware store where I held in my hands a bag filled with large crystals. If I recall correctly, the label said 'contains polyphosphates'. I don't know what its use is, but it was stored next to the water pumps.

"There are many things under the sun."