If we are given $\ce{CH3NC}$ and told to convert it into $\ce{CH3CN}$ by doing some chemical reactions. My attempt According to my textbook there are no chemical reaction of isocyanide conpounds. I tried reduction of isocyanide giving a secondary amine. Then I don't know how to convert a secondary amine to cyanide compound. Hints are too appreciated. Edit: I have got a solution but I don't know whether the reaction are spontaneous. enter image description here

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I have written these reaction on the basis of theoretical knowledge I don't know whether they are spontaneous or not. Correct me if I am wrong somewhere.

  • $\begingroup$ N-Methylformamide is not unstable! It's just a polar solvent, that is bottled and shipped. To my knowledge, neither ADR, nor IATA regulations classify the compound as a particularly dangerous good. $\endgroup$ Feb 14, 2016 at 17:15
  • $\begingroup$ Practically is it possible to carry out this reaction ? $\endgroup$ Feb 14, 2016 at 17:22
  • $\begingroup$ What do you mean by "spontaneous" in this context? BTW from dumb org. chem homework POV it's mostly OK, but has no sense in practice. As Klaus wrote, simply heating it would be real, practical thing. $\endgroup$
    – Mithoron
    Feb 16, 2016 at 20:09
  • $\begingroup$ @Mithoron spontaneous means whether the reactants on reacting gives the product in sufficient amount or not. Or in other words spontaneous can be said as that reaction occur on its own . $\endgroup$ Feb 17, 2016 at 15:34
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    $\begingroup$ You should learn proper words for synthesis. Don't mix thermodynamics here. One asks if reactions are viable or have good yields. $\endgroup$
    – Mithoron
    Feb 17, 2016 at 16:19

2 Answers 2


Just heat it up: Isonitriles can be thermally rearranged to nitriles.

$$\ce{R-NC ->[\Delta] R-CN}$$

Please have a look at some references, such as:

Michael J. S. Dewar, M. C. Kohn, Ground states of $\sigma$-bonded molecules. XVI. Rearrangement of methyl isocyanide to acetonitrile, J. Am. Chem. Soc., 1972, 94, 2704-2706 DOI

Michael Meier, Barbara Mueller, Christoph Ruechardt, The isonitrile-nitrile rearrangement. A reaction without a structure-reactivity relationship, J. Org. Chem., 1987, 52, 648-652 DOI


As far as the sequence outlined in the question is concerned:

  1. The synthesis of methyl formamide from methyl isonitrile is pretty much the opposite of how things are done in real life. Isonitriles, used in the Passerini and the Ugi reaction, have shown to be available by dehydration of formamides, e.g. using $\ce{POCl3}$. For an example with cyclohexyl isonitrile, see Org. Synth., 1961, 41, 13.

  2. N-Methyl formamide is far from being unstable! Release of methyl amine, which, by the way, has a BP around -6 °C might be possible under alkaline conditions.

  3. Making methanol from methylamine, again, is a rather pointless mind game. In real life, methylamine is produced by reacting methanol with ammonia at hight temperatures in the presence of acidic catalysts.

  4. You definitely want to make methyl chloride in the lab! With a BP around -24 °C it's very easy to handle, and the GHS classification with H351 (Suspected of causing cancer) and H373 (May cause damage to organs through prolonged or repeated exposure), this is a real gem. Yes, I'm kidding! Don't do it!

  5. For a nucleophilic substitution with cyanide, the high volatility of methyl chloride again probably doesn't make your life easier, but just shorter.

In summary, my suggestion is simple: Forget about the proposed synthesis! It is laborious, difficult to handle in the lab, and an economical nightmare.

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    $\begingroup$ I have updated my question by putting a solution but I don't know whether the reaction are spontaneous or not. $\endgroup$ Feb 14, 2016 at 16:18

It's too simple guys first you have to convert isocyanide into primary amine. It can be done by hydrolysis of isocyanide, you'll get primary amine and formic acid. Then after getting primary Aimne, on reaction with Cu/500°C or Ni/500°C you will get Cyanide.

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    $\begingroup$ The OP wanted a method which gives a good yield, and a far better way for that is via rearrangment as highlighted in the answer above $\endgroup$ Dec 19, 2018 at 7:17

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