Rhodium
(Chief Bee)
12-18-00 20:31
No 76334
      New synthesis of Phenyl-2-propanones
(Rated as: excellent)
 Bookmark   

Phenyl-2-propanone [Tet Lett 29(24), 2977-2978 (1988)]

To a stirred solution of 2-nitropropene (0.1 mol, 8.7g) in dry CH2Cl2 (300ml) was added benzene (0.5 mol, 39g) at room temperature. Titanium tetrachloride (0.1 mol, 19g) was then added dropwise into the mixture with stirring at the same temperature. After being stirred for 60 min (or when the starting material completely disappears on TLC), water (150 ml) was added and the resultant heterogenous mixture was stirred at reflux for 2h. The organic phase was separated, the aqueous phase extracted with CH2Cl2, and the pooled organic extracts washed with 1M Na2CO3 solution and dried over MgSO4. Evaporation of the solvent followed by vacuum distillation (bp 100-101C at 14mmHg) afforded Phenyl-2-propanone (ca 9g, 70% of theory).

2-nitropropene can be bought, or synthesized as outlined below:

2-Nitropropanol [JACS 67, 205 (1945)]

75.1g Nitroethane, 0.3g calcium hydroxide and 80g 40% formaldehyde solution was dissolved in 75ml ethanol with stirring and was allowed to stand for 48h at room temperature. Distillation at 100-105C/13 mmHg (85-86C/6 mmHg, 99C/10 mmHg) gave 48g 2-nitropropanol (46%) and 14.3g of 2-nitro-2-methyl-1,3-propanediol, the latter remained as a crystalline residue in the distillation flask after distillation of the 2-nitropropanol.

2-Nitropropyl acetate [Ind Eng Chem 32, 34 (1940)]

105 grams of 2-nitropropanol (1 mol) was placed in a 250ml two-necked RB flask equipped with a reflux condenser and an addition funnel, and 110g of acetic anhydride (1.078 mol) was added dropwise with good stirring. The solution was then refluxed for 30 minutes, cooled and poured into 200ml cold water, the organic phase separated and washed with 100ml water, and then vacuum distilled (bp ca 100C at 10 mmHg, yield 90% ). The acetate is a clear water-white liquid with a faint, slightly mustardlike odor, almost insoluble in water.

2-Nitropropene [JOC 15, 8 (1950)]

Sodium carbonate (0.25 mol, 14.5g) is added to a solution of 2-nitropropyl acetate (0.5 mol, 73.5g) dissolved in 50ml benzene and refluxed in a RB flask for six hours. The flask is cooled and the product decanted from the solids. The residue (consisting of sodium acetate) is extracted with 50 ml benzene, dissolved in 100ml water, and the solution extracted with 3x25ml benzene. The pooled organic extracts are dried over anhydrous MgSO4, and the mixture fractionally distilled to afford 2-nitropropene (bp 57C at 100 mmHg).


 
 
 
 
    halfapint
(Hive Bee)
12-19-00 02:26
No 76418
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

There you go, an end-to-end synthesis, starting from the starting points. That's pretty. Titanium tetrachloride is probably available from treating titanium dioxide with hydrochloric acid. Benzene, I'm reading to see if benzoic acid is easily decarboxylated. Uemura already called me for a loose statement about benzoic acid, when I guessed it could bee easily reduced, so I should mention it only with care, but it still excites me that benzoic acid is the endpoint of acid permanganate oxidation of most cyclic natural products. I'm hopeful for sure that easy decarboxylation awaits, to break down the benzene barrier for our acquisition.

Then a concise formula for producing 2-nitro-propene as well, Rhodium you have just enhanced our collective wealth, of course in the metaphoric sense.


turning science fact into << science fiction >>
 
 
 
 
    smiley_boy
(Hive Bee)
12-19-00 02:44
No 76425
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Hey there,

Speaking as one who's seen this before, looked into it, and probobly knows more about it than I should (though I never applied it in this way), let me tell you: 2-Nitropropene is not that easy to make or handle. The first time I saw it used was as an intermediate in the synthesis of alpha-methyltryptamines, whereby it will add selectively to the 3-position, yielding 1-(indole-3-yl)-2-nitropropane, which can be readily reduced to the corresponding amine. It looks great on paper, but nitropropene is somewhat tricky to prepare, very water-sensitive, and a fairly potent lachrymator(there's a sorta funny story about that, which I'm not going to share.) Now a little action and adventure in organic synthesis isn't necessarily bad, and its a clever novel route, so, if you're up to a little challenge, why not?

Incidentally, 2-nitro-1-propanol can be prepared from nitroethane and formaldeyde, too. THe dehydration can be afforded in good yields with POCl3.

Have fun,stay safe, and make me proud!wink
 
 
 
 
    Rhodium
(Chief Bee)
12-19-00 10:06
No 76482
      Re: New synthesis of Phenyl-2-propanones  Bookmark   


Incidentally, 2-nitro-1-propanol can be prepared from nitroethane and formaldeyde, too.



Yes, that is exactly what I outline in the synthesis above.



http://rhodium.lycaeum.org
 
 
 
 
    uemura
(Hive Bee)
12-19-00 11:49
No 76501
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Hi Halfapint, this is Uemura again!

Benzene, I'm reading to see if benzoic acid is easily decarboxylated.

Long time ago, Uemura could buy benzene without much problems (and cheap). Today it's easier to get PCl3 than benzene. Uemura also did some here-and-there investigations how to make benzene and thought of decarboxylation of benzoic acid as well. He didn't find however a proper reference, since no real chemist would produce benzene in quantities via such a route.

Perhaps there are some bees around which could enlighten halfapint and uemura a bit on this topic.

P.S.
Uemura found a 'rediculous' method to arrive at benzene using aniline, diazotitaion and converting this finally to benzene (with low yields!)
 
 
 
 
    psyloxy
(Hive Addict)
12-19-00 14:33
No 76522
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Ph-COOH --> C6H6 is an easy reaction, I've seen it in an old book where they showed what experiments one could make with household chemicals. If memory serves me correctly it was as simple as heating Ph-COOH up to a certain point and collecting the benzene in the distillation flask.

--psyloxy--
 
 
 
 
    halfapint
(Hive Bee)
12-19-00 14:57
No 76523
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Come forth ye coal tar chemists! I draw thee forth, I call upon thee and adjure thee, by Mehitabel, by Baalpheogor, to present thyself now within this circle, with a comely countenance and mild expression, by Ahazrael, by mmmh... oh, hi folks, I was just looking for a sapphire ring I might have dropped in that circle over there, wouldn't happen to have seen it, pay no attention to those little designs, just doodles I made when I was looking, find any car keys they might be mine too, thanks so much...


turning science fact into << science fiction >>
 
 
 
 
    savestheday
(Hive Bee)
12-19-00 18:51
No 76571
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Could 1,3-benzodioxole  aka (methylenedioxybenzene) be used in this reaction or would there be no way to ensure bonding to the proper position? Also, would TiCl4 screw up the methlylene dioxy ring structure?
 
 
 
 
    Rhodium
(Chief Bee)
12-19-00 22:59
No 76615
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Yes, if you use 1,3-benzodioxole, the side chain will be placed in the right position (5). I would guess that some demethylenation would occur, but not extensively, as the reactionis carried out at room temp.


http://rhodium.lycaeum.org
 
 
 
 
    halfapint
(Hive Bee)
12-20-00 13:20
No 76756
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Psyloxy, thanks so much for volunteering the key information I was seeking, with Uemura! My idea of reading includes a broad spectrum of information gathering techniques, some of them let's say proprietary. You posted before I had finished my invocation, whatever works for you. Anyhoo --- you wouldn't care to make a stab at a generalized procedure for production of benzene from the highly controlled precursors leaf litter, grass clippings and compost, would you?

Wouldn't it involve the shredded green wet vegetation, hydrolyzed a while in dilute mineral acid, then oxidatively blowing the hell out of it with permanganate? Apres, you'd have benzoic acid in with an unspeakable shitload of other products. It isn't as simple as steam distilling and then taking the organics extracted with a countercurrent of diethyl ether, drying then removing the ether and light volatiles, pyrolizing the organic residue and taking the fraction which comes over at the 80o boiling point of benzene, is it?

Volunteering, it always gets you more work.


turning science fact into << science fiction >>
 
 
 
 
    Teonanacatl
(Hive Bee)
12-20-00 20:26
No 76844
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Peony roots contain fairly large amounts (11000 ppm) of benzoic acid if that's any help...


Begin with the dissolution of superfluous matters
So that desire and consciousness are free
 
 
 
 
    smiley_boy
(Hive Bee)
12-20-00 21:06
No 76857
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Sorry; my mistake.blush
 
 
 
 
    Teonanacatl
(Hive Bee)
12-20-00 21:22
No 76861
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Could gallic acid theoretically be decarboxylated and then used in this method? I'm wondering simply because it is an easily available compound via. witch hazel extracts. Methylation would have to be performed at some point...


Begin with the dissolution of superfluous matters
So that desire and consciousness are free
 
 
 
 
    lugh
(Stranger / Eraser)
12-20-00 21:48
No 76869
      Re: Benzene  Bookmark   

Many benzene derivatives occur in nature, e.g. oil of bitter almonds, benzoic acid, salicylic acid, and hippuric acid, while others are obtained from the destructive distillation of organic substances, especially of coal.
The destructive distillation of coal yields (a) gases (illuminating gas); (b) an aqueous distillate containing ammonia and its salts, (c) coal-tar; and (d) coke. Coal-tar is the chief source of benzene derivatives, and is formed in the manufacture of coal-gas for illuminating, purposes, and in "coke ovens" used for the production of high-grade coke for metallurgical purposes. In both cases coal is distilled from closed retorts at relatively high temperatures, about 1000' C, and the main difference between the two processes is the nature of the coal used. For gas, making a bituminous coal containing 32-40 per cent of volatile matter is used, and in order to obtain the maximum yield of hard coke bituminous coals containing from 18-32 per cent of volatile matter are employed.
The tar from the two processes is much the same. At the present time numerous low-grade coals, e.g. cannel coal, lignite or brown coal, and even bituminous shales, are distilled at comparatively low temperatures (500-600' C.) in order to obtain oils, and, in the case of cannel coals, smokeless fuel for household purposes, coalite. The tar produced in all these cases is essentially different from the coal-tar obtained from gasworks and coke ovens. It consists largely of paraffin hydrocarbons, and is valueless for the manufacture of dyestuffs, explosives, etc., but yields valuable illuminating and fuel oils.
When coal-gas was first generally used for illuminating purposes (1813) the tar was regarded as a waste product, and could only be used as fuel, and its value as the source from which important synthetic dyes, perfumes, explosives, medicinal drugs, and photographic developers could be manufactured was only gradually recognized. For many years after the introduction of coke ovens for the manufacture of metallurgical coke, the ammonia and tar formed at the same time were not collected (so-called bee-hive ovens), but at the present time the great majority of the ovens are of the closed type, and are provided with by-product recovery plant. Still more recently, as the demand for benzene and toluene has increased, it has become customary to recover the benzene and toluene contained in the gas from the coke ovens, and even from the gas from gasworks, although this removal appreciably diminishes the illuminating power of the gas. The benzene hydrocarbons are usually removed by passing the gas through scrubbers containing creosote oil, which absorbs the hydrocarbons, and these can be afterwards isolated by heating the creosote oil or subjecting it to steam distillation. The amount of benzene and toluene in coal-gas is, roughly, About 15 times as much as that contained in the tar formed at the same time. In coke-oven gases the amount is only about half this. By this method of extracting benzene and toluene from the gases the amounts of these materials for the manufacture of explosives etc. has been increased enormously.

The following figures will give some idea of the importance of the coal-tar industry: In 1914, in Great Britain, about 14.5 million tons of coal were coked in by-product coking plants and in the USA  about 20 million tons were treated in recovery coke ovens, and about 20 million tons in gasworks. In the USA the output of crude benzol was about 14.5 million gallons in 1914 and this was increased to 40 million gallons in 1917. Coal-tar contains as many as 200 different chemical substances these are not present in the coal itself, but are formed during the distillation. During the past thirty years Investigators have attempted to isolate compounds from coal itself by extraction with solvents, such as chloroform (Keinsch, 1910), pyridine (Bedson, 1908), benzene (Pictel and Ram, 1911), but so far few relationships have been established between the, different materials present in coal and the chemical compounds present in tar (cf. Tideswell and Wheeler, J. C. S. 1919, 115, 619). The most important compounds present in coal-tar are benzene, toluene, xylenes, phenol, cresols, naphthalene, and anthracene. Among the other compounds present are homologues of benzene, especially the methyl homologues; complex hydrocarbons, such as diphenyl, phenanthrene, fluorene, acenaphthene, chrysene and retene, indene and its homologues, and homologues of naphthalene; thiophene, aniline, pyridine and its homologues; quinoline, euorene, quinoline, pyrrole, indole, carbazole, and acridine. Most these are of little commercial importance, as the amounts present are small and their isolation from the tar is difficult. Many of the hydrocarbons present in the tar are probably formed by the pyrogenic polymerization of acetylene, as this hydrocarbon when heated yields many of the products present coal-tar (R. Meyer and H. Frieke, B. 1914, 47, 2765). The crude tar contains appreciable amounts of water, and as to be dehydrated before it can be distilled. Numerous methods are adopted, e.g. centrifuging the warm tar; heating the tar, allowing the water to rise to the surface, and removing it by a draw-off cock, or allowing the wet tar to come in contact with the hot vapour from another lot of boiling dehydrated tar. The actual distillation is carried out in iron stills directly fire-heated. In many tar distilleries continuous stills are employed; in others intermittent distillation is used, the pitch being removed from time to time and a fresh charge of tar introduced. The fractions collected vary in different distilleries, but, as a rule, in the first distillation the following are collected: (1) First runnings up to 105  or 110'; this contains water, ammonia, and some light oil (2) Light oils up to 210'  (3) Middle oil or carbolic oil up to 240' (4) Creosote oil up to 270' (5) Anthracene oil above 270' (6) Residue in the still=pitch. The relative amounts of the different fractions vary considerably in different countries and different districts, but the following are fairly typical values for 1 ton of tar -Light oils, 12 gall; carbolic oil, 20 gal; creosote oil, 17 gal; anthracene oil, 38 gal; and pitch, 11 cwt. Calculated on 1 ton of tar, the yields of important products are:-Benzene and toluene, 25 lb., or 1.1 per cent; phenol, 11 lb., or 0.5 per cent; cresols, 50 lb., or 2.2 per cent; naphthalene, 180 lb., or 8 per cent; creosote, 200 lb., or 8.8 per cent; and anthracene, 6 lb., or 0.27 per cent.

The light oils, including those from the first runnings, give rise to 60-65 per cent of benzene hydrocarbons, 12-15 per cent of naphthalene, 8-10 per cent of phenols, and 1-3 per cent of pyridine bases. The phenols are readily removed by treatment with caustic soda solution, and bv treatment with dilute mineral acids.the pyridine bases The neutral substances, on further fractionation under varying conditions, yield 90 per cent benzol, 50 per cent benzol, 30 per cent benzol, and solvent naphtha. The numbers 90, 50, and 30 denote the percentage of the oil which passes over below 100' C., and not the actual benzene content of the oil. 90 per cent benzol contains 81 per cent of benzene, 15 per cent of toluene, 2 per cent of xylenes, and 2 per cent of impurities; and 30 per cent benzol contains respectively 13.5, 73.4, 11.7, and 11.7 per cent. From these crude benzols, by careful fractionation, pure benzene, toluene, and xylenes can be isolated.
In addition to the compounds, such as benzene, toluene, naphthalene, phenol, and anthrace, which are actually isolated and form important articles of commerce, a number of products consisting of complex mixtures are also manufactured. The most important of these are (1) solvent naphtha, which is used as a solvent for rubber in preparing waterproof fabrics and also for burning purposes, and (2) creosote oil, which is used in enormous quantities for pickling timber for use as railway sleepers, posts, and other purposes. For hydrogenation of coal cf. Bergius, Chem. Age, 1927, 134.
Many methane derivatives, e.g. alcohol, yield a mixture containing a large number of the derivatives of benzene when their vapours are led through red-hot tubes. Acetylene, C2H2, polymerizes at a low red heat to benzene, C6H6, (Berthelot)
Benzene is formed when benzoic acid is distilled with soda-lime: C6H5COOH = C6H6 + CO2

 
 
 
 
    halfapint
(Hive Bee)
12-21-00 01:21
No 76910
      Re: Benzene  Bookmark   

That's the spirit, this reading biz gets easier with practice, just let other folk's fingers do the walking, yassuh. Dad gum nitroethane, dad gum acetic anhydride, let me tell you folks, these things can bee made at home, or if you're real good, out in a solar-powered tent. Thing about it is, they're pretty fair projects in their own right. I'm needing industrial scale "hazmat" storage for intermediates and fortuitous by-products of other reactions. Environmental concerns line up with economic sense on the single recycling principle, never throw anything away when you're working with chemicals, beecause everything is made of something, and to call something waste is the action of admitting you don't know and don't care what's in it. "Pollution is matter in the wrong place," R. Buckminster Fuller.

Logical necessity, my dear friends, is going to drive us to take the action we dread and fear above all others, working cooperatively with other (local??) associates. Yes, I am quite aware of the Bee Guiding Principle, security considerations are paramount. But there is a practical limit to the number of little bottles of self-made substances a lone bee can collect in safety, whether or not security issues are included within the determination of safety factors. So as we gear up toward the threshold of our psychosocial revolution in which sheer availability of psychedelic compounds will force spiritual sea change in the very basis of bourgeois law-infected culture, we'll come to a point where a single bee will exceed private capacity for secure storage of purified "incidental" intermediates, substances which are not immediately incriminating in themselves, but are just not facile to explain in terms of consumerism and commercialism. It's a damn big hobby.

(Why the fuck did we let the republican fascist pig regimes get away with establishing the implicit legal principle that every item in your posession must be explicable in money terms of intended use? Is there no definition of utility which does not involve inherent greed to a pig judge?)

Well, I don't know how we can organize a storage and/or exchange capability for sensitive-not-hot materials in keeping with short term personal security considerations, I just get the feeling we ought to try to figure it out. Had we a nonlocalized club with anonymity and tranfer point protection for origin to swap our nobody-knows-what-they're-useful-for substances, it would bee preferable in security terms than any sort of local arrangement. None of us really want to know that our neighbor down the street is a bee. Please note that this sort of anonymous exchange club does not constitute criminal conspiracy in its conception, even though it might bee set up for "listed" substances (which are not direct precursors to specific drugs and usable only for that purpose) beecause it's damn well legal to have, to hold, and to damn well trade in listed substances in private exchange with fellow hobbyists. I have in mind something a bit less public than online auctions that we're familiar with, with transhipment points in no man's land.

Well thinking a bit more deeply about it, this is hotter than blue blazing hell. Probably best forgotten. The rub comes with theft prevention, ol' Half-a-Pint thinking simply in the old school style that we discourage theft and fraud just by letting people beecome aware that it's a really, really, really dumb idea to steal from us. That kind of sort of does make the whole idea into a criminal kind of sort of idea, and shoots down the civil liberty crusading aspects of establishing that it's legal to have legal chemicals. There's an idea around here somewhere, but I can't find it right now.




turning science fact into << science fiction >>
 
 
 
 
    Ritter
(Newbee)
12-23-00 05:05
No 77366
      Re: Benzene  Bookmark   

Rhodium,

Will this rxn work with nitroethylene to produce phenylacetaldehydes?  There is a pretty straight-forward but tedious synth for nitroethanol in Org Syn Collective Volume V, Page 833.  This could be easily dehydrated to form nitroethylene w/ SOCl2, POCl3 or by your above method of course.  
 
 
 
 
    halfapint
(Hive Bee)
12-24-00 09:32
No 77606
      Re: Benzene  Bookmark   

Somebody oughta run an experiment series on pyrolysis of natural products in the presence of hydrogen, no catalyst. This would give a completely different set of breakdown products than dry distillation starting with excess oxygen, and of greater intrinsic value.

Acetylene into the tube furnace, yeah, forgot about that benzene route.


a half a pint's a half a pound a half the world around around
 
 
 
 
    baalchemist
(Hive Bee / Eraser)
12-28-00 08:43
No 78285
      Re: Benzene  Bookmark   

Jesus this is a sweet post, reminds me of the old hive. I bet you can still get Benzene in Mexico fairly easy still.
 
 
 
 
    Beaker
(Hive Bee)
12-29-00 08:01
No 78419
      Re: Benzene  Bookmark   

I remember seeing a related reaction if anyone is interested. 1-dimethylamino-2-nitroethylene and 4-bromoindole in TFA gave the 3-nitroethene-4-bromo indole in >80% yield. I forget the source, but if anyone has access to Bielstein, I'm sure you can find it.
 
 
 
 
    Scooby_Doo
(Newbee)
02-23-01 06:36
No 174982
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

On applying Rhod's ref Tet Lett 29(24), 2977-2978 (1988)
to 1,2 methylenedioxybenzene gave only a black tary mess. More success may be had using catechol to avoid demethylation, or perhaps running it at very low temps.

Scooby 
 
 
 
 
    Rhodium
(Chief Bee)
02-23-01 19:26
No 175076
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Could you try the reaction out on benzene, just to verify that it works with 2-nitropropene? The original article used other (cyclic) nitroalkenes.


http://rhodium.lycaeum.org
 
 
 
 
    Scooby_Doo
(Newbee)
02-25-01 03:37
No 175345
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Sorry Rhod I probably can't get my hands on any Benzene because of its general unpleasantness.
I am positive that the MD bridge was the problem. A little separate experiment showed the Titanium tetrachloride reacted instantaneously with 1,2 methylendioxybenzene turning it into red tar. As for the actual reaction it definitely produced some sort of complex which fell out of solution. However the mixture had turned so black (from a fluro clear green) it was obvious that something had gone wrong.

Scooby
 
 
 
 
    Rhodium
(Chief Bee)
02-25-01 19:45
No 175443
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Toluene then? 4-methyl-P2P isn't that useful, but at least you can prove that the reaction works.


http://rhodium.lycaeum.org
 
 
 
 
    Scooby_Doo
(Newbee)
02-26-01 02:37
No 175492
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

I was thinking the same thing, I also wouldn't mind looking at catechol which would be a little more useful.
 
 
 
 
    Osmium
(Stonium's Main Man)
02-26-01 13:02
No 175552
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Those OH groups will bind to the TiCl4, rendering it ineffective.
Did you work your reaction up? Never judge your reactions by what they look like, only after proper workup can you be sure of the results.

Use another catalyst, what about SnCl4? Or anhydrous ZnCl2. Activated aromatics like anisole, methylenedioxybenzenes and other phenolethers should undergo that reaction much easier than benzene, which is terribly unreactive compared to them, meaning that the reaction might take place at lower temps, with more selective (=lower reactivity) catalysts etc.
 
 
 
 
    Rhodium
(Chief Bee)
02-27-01 08:24
No 175700
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

The original article used toluene and nitrocyclohexene with the reaction conditions described.


http://rhodium.lycaeum.org
 
 
 
 
    Scooby_Doo
(Newbee)
02-27-01 08:57
No 175703
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Your right I should have finished with a proper workup. However whatever it was I spent hours getting it out of the flask with the blob having a texture of tary charcoal.

A lower temp is a definite possibility, the reaction temp got to around 38-39 deg. With the color starting as a ketone fluro yellow/green going to a really dark brown to charcoal black after a temp of 35 was reached. Maybe 0 or even colder might be quite a good idea. (I might try adding the TiCl4 to the 1,2 methylenedioxybenzene at different temps the one that doesn't produce tar is the temp to run with.)

As for using different types of catalysts could this change the regioselectivey of the reaction products being only para substituted?

Scooby
 
 
 
 
    Osmium
(Stonium's Main Man)
02-27-01 16:42
No 175755
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

The bulkier they are the more para product you should get (steric control). Another factor is that all those catalysts like the oxygen a lot and will bind to it, possibly favoring the o position. That's why weaker (=more selective) catalysts might give better yields. Difficult to say without hitting the books.
Also limiting the reaction time works for reversible reactions due to kinetic control (once all has reacted the reaction is stopped to avoid rearrangements). Dunno if that applies to this kind of reactions though.
 
 
 
 
    Scooby_Doo
(Newbee)
04-15-01 08:58
No 184263
      Re: New synthesis of Phenyl-2-propanones
(Rated as: good read)
 Bookmark   

Here is some very useful refs in the production of 2-Nitro Propene:

JACS 98 4679 (1976)
Synthesis 407 (1980)

The one which the above lead to J. Chem. Soc 1947 1471-2

I can't find the above one but I did find the CA for it. (Either 1947 or 1948 4907 and in the same CA in the patents section Brit 595,282 which is pretty much the same as the first one.)

Nitro alcohols are heated with a phthalic anhydride to give nitro olefins, here's the deal.
1 mole of 2Nitro-1-Propanol and 1.35 mole of phthalic anhydride were placed in a distillation app. A vacuum of 80 mm was applied and the flask was heated. Everything melted a 130-140 deg tiny bubbles became evident at 150-160 deg. The reaction began and heating was adjusted to control the rate. It stayed around 162 deg and then dropped down to 155 deg. More heat was applied and the reaction stopped when it reached 180 deg. (all these temps are at 80mm of Hg)

The receiving flask contained water and a ketone yellow colored oil. The vac was released with N2 being drawn in. Don't let any air into the flask otherwise the 2-Nitro Propene breaks down extremely fast as well a being very volatile, the receiving flask was in an ice bath for the entire reaction. If air does get to it a orange vapour is emitted form it which as the same hurt factor as Bromine. The oil will rapidly turn green and will break down into tar in a few days. The oil however stores very well in the freezer under N2, for months.

In the ref they went and distilled straight away which Batman tried but was pretty silly since the water causes problems. A better approach is to dry with molecular sieves (which worked really well) then distil.

Scooby
 
 
 
 
    jim
(Hive Bee)
04-20-01 18:56
No 185494
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

From Rhodium's site, the microwave Henry condesation text:

"...

Several reagents such as phthalic anhydride,[12,13] methanesulfonyl
chloride,[14] dicyclohexylcarbodiirnide (DCC), [15] pivaloyl chloride, [16,
17] ammonium acetate-acetic acid [18, 19] and amines[7, 19] have been used
for the dehydration of the ensuing b-nitro alcohols.  ..."

I was thinking that the mere addition of the formaldehyde to the nitroethane with ammonium acetate and acetic acid would afford the nitropropene directly.  Perhaps even the addition of microwave heating would improve yields or speed up the process.  I can't imagine that nitropropene reacts too differently from other nitropropenes...

If one were to use a substituted ring one could substitute the nitroethane with nitromethane (which is easier to obtain OTC) and produce a substituted phenethylamine.

?
 
 
 
 
    Rhodium
(Chief Bee)
04-21-01 02:50
No 185572
      Re: New synthesis of Phenyl-2-propanones  Bookmark   

Nitroalcohols (from the condensation of nitroalkanes and aldehydes) dehydrates to the nitroalkene MUCH easier if the aldehyde is aromatic.


http://rhodium.lycaeum.org
 
 
 
 
    Scooby_Doo
(Hive Bee)
09-04-01 17:10
No 210023
      Re: New synthesis of Phenyl-2-propanones
(Rated as: excellent)
 Bookmark   

Application of this synthesis to the preparation of MDP2P

To a 3-necked 500 ml flask under a nitrogen atmosphere was added 300 mls of dry DCM, 0.1 mole of 2-Nitropropene (8.7g) and 0.5 mole of 1,3-Benzodioxole (61g). The flask was then secured within a dewar flask sitting on top of a magnetic stirplate. Dry ice was added to the dewar flask which was filled with acetone until a temperature of approx -78 C was acquired. Once the internal flask temperature of -70 C was reached, 0.1 mole (19g) of TiCl4 was dripped slowly into the stirred solution. The temp started to rise so the addition was controlled to keep the internal flask temp around -60 to -70 C. The flask was then stirred for 30 mins at -70 C, by which time the precipitate which formed from the addition had dissipated.
The dewar flask was removed and the stirring solution was allowed to warm up to room temperature. (The black solution will change viscosity and colour.)

NEF REACTION

100 mls of water was added to the solution which was then  refluxed for 2 hours. During the reflux a brown gas (probably NO2) is evolved.

WORKUP

The flask was cooled and vac filtered (cleans it up a lot) the water layer seperated and discarded. The organic layer was then washed with 3x 200 mls of 10% NaOH sol and 1x 200 mls of a brine solution. It was then dried with magnesium sulfate, the DCM evaporated and resulting orangey/yellow oil vac distilled. The 1,3-Benzodioxole came over at 40-45 C at 10 mbar then a fluoro yellow/green oil (MDP2P) started distilling at 135 C at 3 mbar.
Yields 8g of MDP2P, 45% form 2-Nitropropene or 23.5% form 1,3-Benzodioxole. (Worked out from the 1,3-Benzodioxole not recovered during the vac distillation.)
 
 
 
 
    foxy2
(Distinctive Doe)
10-02-01 23:50
No 219572
      Alternate 2-nitropropanol synthesis
(Rated as: good read)
 Bookmark   

Technology of 2-nitro-1-propanol.    
Polovnyak, V. K.; Kolpashchikov, M. V.
Khim. Khim. Tekhnol.  (1975),  18(3),  497. 
CODEN: IVUKAR  Journal  written in Russian.  CAN 83:9077 

Abstract

Optimal conditions for prepn. of O2NCHMeCH2OH from EtNO2 and HCHO (as paraformaldehyde) were: 10N KOH as catalyst, use of elevated temp., and reaction time 2-3 min.
 

Do Your Part To Win The War
 
 
 
 
    jim
(Hive Bee)
10-03-01 06:48
No 219710
      Re: Alternate 2-nitropropanol synthesis  Bookmark   

Great job.
 
 
 
 
    Rhodium
(Chief Bee)
10-03-01 08:45
No 219742
      Re: Alternate 2-nitropropanol synthesis
(Rated as: good read)
 Bookmark   

Another reference of the nitropropene/benzene condensation can be found in JOC 54(4), 733-734 (1989), but they use CF3SO2H instead of TiCl4 (85% yield in 1 min, at -40C).