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Author Topic: How can i synthesize m-nitro toluen??  (Read 5609 times)

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hsvilenov

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How can i synthesize m-nitro toluen??
« on: April 01, 2006, 06:50:22 AM »

can give me an idea how can i synthesize 1-metyl 3-nitro benzen(m-nitro toluen)
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HP

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Re:How can i synthesize m-nitro toluen??
« Reply #1 on: April 01, 2006, 07:20:44 AM »

Good question :)
In direct nitration toluen you'll obtain only o- and p-nitro toluenes because the resonance forms..
m-nitro toluene may be synthesized indirectly from p-toluidine(p-NH2 toluene which obtained from reduction of p-nitro toluene with Zn/HCl ). para-toluidine is then acetylated with acetic anhydride to the coresponding acetylated base which further with HNO3 is nitrated on m-position of CH3 group. After that with NaOH you;ll hydrolyze the amide to the free NH2 group obtaining p-amino m-nitro toluene. This intermediate in diazotation reaction with NaNO2+HCl giving diazonium N2Cl salt which is reduced(liberating N2) with stanium chloride in alkaline media(Mayer) to the desired m-nitro toluene  :P
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o alquimista

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Re:How can i synthesize m-nitro toluen??
« Reply #2 on: April 01, 2006, 10:19:26 PM »

Here is HP his post as a chemical equation.
« Last Edit: April 01, 2006, 10:24:55 PM by o alquimista »
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HP

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Re:How can i synthesize m-nitro toluen??
« Reply #3 on: April 02, 2006, 05:08:22 AM »

Quite a precise scheme alquimista ths!
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o alquimista

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Re:How can i synthesize m-nitro toluen??
« Reply #4 on: April 02, 2006, 09:40:14 AM »

Some extra information: Both -NH2 and -NHCOR are o,p-directors. However in a reaction mixture containing a Lewis acid such as H2SO4, HNO3, or AlCl3 the amino group becomes a m-directing, deactivating NH3+ group.
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o alquimista

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Re:How can i synthesize m-nitro toluen??
« Reply #5 on: April 02, 2006, 10:09:31 AM »

Maybe its possible to do it the other way around; first the nitro group and then the CH3.

Nitrate benzene, or start with nitrobenzene an m-director.

Then use methane iodide and a catalyst. Thing is you can't use a smaller halogen then I. Because smaller methylhalogens have a BP below room temperature and are very carcinogenic (not a fun combination :P). And does CH3I with AlCl3 or another catalyst work?

If not then reaction with HCOCl + AlCl3, or para-formaldehyde, followed by a reduction might work. Although reaction with para-formaldehyde can (as I have once synthesized after discovering it as a by-product of a chloromethylation reaction) also give a bis-aromatic product Ar/\O/\O/\Ar.

---        

PS: This hole post might be nonsense, but I am just wondering whether a shorter reaction route is possible.

Also if you were to synthesize a bigger alkyl group than methyl, the nitro group first method would definetely be easier and arguably better than starting from the alkyl-aromatic.  

Another point I would like to make with this post is that in synthesis problems creativity is of crucial importance.
« Last Edit: April 02, 2006, 10:41:21 AM by o alquimista »
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HP

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Re:How can i synthesize m-nitro toluen??
« Reply #6 on: April 03, 2006, 06:23:09 AM »

Aha if nitrobenzene is m-director then with Br2/FeCl3 you'll obtain m-bromo nitrobenzene. Then CH3I/Mg/ether as  Grignard reacent reaction will lead to m-nitro toluene i guess...
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movies

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Re: How can i synthesize m-nitro toluen??
« Reply #7 on: April 12, 2006, 08:11:18 AM »

Grignard reagents sometimes add to nitro groups.  Check out the Bartoli Indole Synthesis.
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HP

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Re: How can i synthesize m-nitro toluen??
« Reply #8 on: April 12, 2006, 08:31:56 AM »

Interesting synthetic route for indole synthesis using Grignard, movies. May be with m-nitro bromobenzene it wouldnt work the same but using the highly reactive MeMgI make some doubts for some kind chemical interactions with NO2 group i guess. May be similar as shown in detail mechanism in Bartoli synthesis. But also the classical reaction Grignards with Ar-X will take place most and the final product predominanetly be the desired :) Really interesting to be checked this route if alredy no one had done it in lab...
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