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Could you suggest a reagent or procedure to transform an aliphatic primary amine to the corresponding nitro compound.

I know this is a bit backwards of a request because the usual procedure is the reduction of nitro groups to their corresponding amine, but there is a need of its electron-withdrawing properties for a subsequent condensation to form the intended intermediate. If this approach could be solidified, then it would make things a lot easier for this recent graduate, as the starting material is a lot less expensive.

I have found references to ozonolysis, but am unsure of it, as I have no previous experience with these sorts of reactions. I have also seen in abstracts where it is discussed formation of the diazonium compound, which was the used to form the nitro compound. There are a couple of others I have come across, but I am not sure of their efficacy or plausibility.

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2 Answers 2

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Using silica gel, primary amines can be oxidized to their corresponding nitro compounds using ozone ($60$-$70 \%$ yield). In this paper, dry silica gel (dried for $24\ \mathrm{h}$ at $450^\circ \mathrm{C}$) was mixed with an amine. The silica gel (ca. $\mathrm{30\ \mathrm{g}}$) containing the amine ($0.1$-$0.2\ \mathrm{wt/wt \%}$) was cooled to $-78 ^\circ \mathrm{C}$, and a stream of $3 \%$ ozone in oxygen was passed through it.

Aliphatic amines and aromatic primary amines are rapidly and effectively oxidized to nitro compounds by dimethyldioxirane ($80$-$90 \%$ yield). Dimethyldioxirane is prepared by reaction of OXONE ($\ce{2KHSO5 \cdot KHSO4 \cdot K2SO4}$) with buffered aqueous acetone. In a typical reaction, $0.7\ \mathrm{mmol}$ of amine in $5\ \mathrm{mL}$ acetone is treated with $95\ \mathrm{mL}$ of dimethyldioxirane in acetone ($0.05\ \mathrm{M}$). The solution is kept at room temperature for $30\ \mathrm{min}$ with the exclusion of light.

Oxidation of amines to nitro compounds in high yield has also been carried out using oxyacids like peracetic acid, peroxytrifluoroacetic acid, and meta-chlroperoxybenzoic acid, though the anhydrous forms of these acids are hazardous and difficult to use.

Ono, N. The Nitro Group In Organic Synthesis; Wiley-VCH: New York, 2001.

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  • $\begingroup$ Thanks for the reply. I will take a look into these methods. $\endgroup$
    – Jeffrey Schultz
    May 23, 2016 at 6:33
  • $\begingroup$ The peroxy acid oxidation was another method I came across in my original query but was curious about the conditions. Thank you for the reference! I started to put in the request for that reference and realized it was link to a version available on the web. Nice! $\endgroup$
    – Jeffrey Schultz
    May 23, 2016 at 6:47
  • $\begingroup$ @JeffreySchultz Happy to help! $\endgroup$
    – ringo
    May 23, 2016 at 6:50
  • $\begingroup$ I am also going to attempt the second reaction you have provided. The 80-90% yield reported is somewhat of a confidence booster. Beyond that it will be whatever is easier or what further advice I receive on the matter. We have a few guys that might be able to provide some guidance on the ozone reaction. $\endgroup$
    – Jeffrey Schultz
    May 23, 2016 at 13:04
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These are the 2 methods I could think of to convert primary amine to corresponding nitro compounds.

The first method:enter image description here I am not so sure about this method. I think the yield would be low.

Second method:http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1099-0690(199804)1998:4%3C679::AID-EJOC679%3E3.0.CO;2-W/abstract

Here is an abstract from the paper:- Primary aliphatic amines are oxidized with tert-butyl hydroperoxide to the corresponding nitro compounds in 50−98% yield using Zr(Ot-Bu)4 as the catalyst.

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  • $\begingroup$ Thanks for the reply. I will take a look into these methods. $\endgroup$
    – Jeffrey Schultz
    May 23, 2016 at 6:33
  • $\begingroup$ Happy to help others learn :) $\endgroup$
    – ShankRam
    May 23, 2016 at 7:41
  • $\begingroup$ This seems to be a very attractive route. It's sad that copper seems to have been lost in the shadow of palladium. I believe this will be a very good starting point for my attempts as everything is on-hand. I started looking into diazonium chemistry more and have found some very interesting reaction possibilities, however, most of them fall outside the scope of the current task. Introduction of the cyano group with CuCN seems most interesting, but it looks to be falling in popularity due to cyanide toxicity even with its negligible water solubility. $\endgroup$
    – Jeffrey Schultz
    May 23, 2016 at 11:52
  • $\begingroup$ As for yields, they will be determined, and if there is issue, it at least justifies the more tedious procedures, in my mind at least. $\endgroup$
    – Jeffrey Schultz
    May 23, 2016 at 12:04
  • $\begingroup$ Diazonium reactions are very neat. It helps with a lot of conversions. And yes, palladium does shadow copper, maybe because of its versatility. $\endgroup$
    – ShankRam
    May 23, 2016 at 16:20

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