[darkdevil]

Dear,
I am trying to do the below nitration. I tried to do it when R group is Methyl, or hydroxy and the reactions gone well, and I can collect my crystallized yellow products by pouring it into ice and then filter.  However when R group is long alkyl chain like a butyl group. The nitration gave me an organe red sticky paste and even a second trial gave me black tar. I assume this is due to the stronger activating effect of the butoxyl group and over nitrated my material.  how can I do nitration in a milder condition?

[discodermolide]

With a long alkyl chain the compound becomes very lipophillic and difficult to crystallise. So it may not be the chain reacting, unless it has some functionality in it.
I used to work with phospholipids, with 2 saturated C₁₉ to C₂₀ chains. There I used to crystallise from methyl ethyl ketone at -20°C.
I don't know if this will work in your case.
Keep trying and it will eventually crystallise.

[darkdevil]

With a long alkyl chain the compound becomes very lipophillic and difficult to crystallise. So it may not be the chain reacting, unless it has some functionality in it.
I used to work with phospholipids, with 2 saturated C₁₉ to C₂₀ chains. There I used to crystallise from methyl ethyl ketone at -20°C.
I don't know if this will work in your case.
Keep trying and it will eventually crystallise.

So the orange sticky thing could be my product?

[discodermolide]

Yes, it could be. You should never throw anything away until you are sure you have your product.

[darkdevil]

Yes, it could be. You should never throw anything away until you are sure you have your product.

I didnt throw it away. But it seems that the longer the chain of the R group, the more intense is the color of mt final product.
With R = C₈H₁₇, the product is dark and viscous. Could it be oxidation?

[discodermolide]

It could be, but not due to the chain, it's probably the aldehyde that's causing the problem.
Also the longer the chain the less soluble it will be, so the reaction time may well increase to the point where the SM starts to decompose.

[AlphaScent]

You could protect the aldehyde.  It shouldnt affect the direction of the reaction.

[darkdevil]

Or Can I nitrate the phenol form (R = H) and then turn it into the ether I want?

[discodermolide]

Why not try it? Chemistry is an experimental science.

[zsinger]

I like the Nitration idea first……..doesn't that do something (i.e. give some properties) to your ring which kindly lends itself it your product? (hint hint!)
           -Zack

[Dan]

With a long alkyl chain the compound becomes very lipophillic and difficult to crystallise. So it may not be the chain reacting, unless it has some functionality in it.
I used to work with phospholipids, with 2 saturated C₁₉ to C₂₀ chains. There I used to crystallise from methyl ethyl ketone at -20°C.
I don't know if this will work in your case.
Keep trying and it will eventually crystallise.

So the orange sticky thing could be my product?

If you can't purify by chromatography, you could try to crystallise it as the 2,4-DNP imine. Or try a sodium bisulfite adduct.

[408]

I agree with disco, you may have the product, however due to chain length it gets stickier and more likely to hold impurities. 

I would also give a shot dissolving precursor in acetonitrile at -20 or so, and adding stoichiometric NO2BF4 followed by a acetate quench after monitoring the reaction.  I have had good luck with this method for nitrations that come out less pure than desired. 

[darkdevil]

The orange paste was really my product
Since I continued the next step using the crude paste like substance as the starting material for the next step, considerable amount of the product was given out.
Im just surprised about that.

[darkdevil]

Indeed I still cannot get a powder form of the alkoxy nitrobenzaldehyde which a paper mentioned with a similar structure like mine.