Currently, I'm trying to find ways of making imidazole/imidazolium salts at home for ionic liquids, and one method that I came up with to produce an
imidazole precursor is the cyclization of ethane-1,2-diamine with triiodomethane. The final product of such a reaction would be a cyclic imidamide
(specifically a 2-imidazoline/imidazolinium salt), which could then be dehydrogenated into the corresponding imidazole/imidazolium. I've determined a
couple different reaction procedures, and the biggest questions I have so far are:
Is a condensation between HCI3 and EDA (either protonated or conjugate base) feasible or even possible to begin with? How
controllable is such a reaction, i.e., would it tend to have side reactions that would make it infeasible? (One that concerns me is polymerization.
Not sure if polymerization would occur preferentially over cyclization, but I'm still worried about it.)
Would HCI3 react more readily with the fully protonated EDA or the neutral conjugate base? (I'm betting on the latter.)
Ideally, the reactants will combine in a 1:1 molar ratio, but is/are there any particular way(s) the reactants should be combined so as to
optimize short-term reaction stoichiometry? (i.e., to favor cyclization over possible polymerization)
I also have some questions about the dehydrogenation but I think I'll save those for later.clearly_not_atara - 29-3-2017 at 21:27
Looks like you can do pretty well with hexamine, ammonium acetate, and a diketone:
Diacetyl can be had by rxn of butanone with nitrous acid and hydrolysis of the resulting oxime.
If I really wanted to do it with chloroform I'd use very strong base and try to force a reaction between ethylenediamine and dichlorocarbene. This
should actually make an isocyanide but the amino-isocyanide might cyclize to imidazoline. It's 5-endo-dig so it's legal
[Edited on 30-3-2017 by clearly_not_atara]
[Edited on 30-3-2017 by clearly_not_atara]CuReUS - 30-3-2017 at 06:17
the amino-isocyanide might cyclize to imidazoline. It's 5-endo-dig so it's legal
according to wiki,nitriles cyclise with diamines to given imidazolines-https://en.wikipedia.org/wiki/2-Imidazoline#Synthesis
and by "legal",you mean its allowed to be formed according to balwin rules,right ?Azane - 1-4-2017 at 07:49
"If I really wanted to do it with chloroform"....
So what about *iodoform*? I could be wrong, but I assume HCI3 is at least somewhat more reactive towards nucleophiles than
HCCl3, which is one reason why I mention using the former as opposed to the latter. For instance, HCI3 reacts spontaneously with
AgF to yield HCF3 and AgI, and F- is arguably a weaker base and nucleophile than an amine.
The other reasons I want to use HCI3 are that it is 1) much easier to make at home via the haloform reaction than HCCl3 (iodine
easier to handle and use than either chlorine or hypochlorite salts), and 2) easier to handle and use (solid HCI3 vs liquid
HCCl3). Still though, that's an interesting possibility, creating an isonitrile intermediate.
@CuReUS, my goal is imidazole or an imidazolium salt, not just ionic liquids in the broad sense that also includes deep eutectic solvents. And I am
aware of the nitrile + diamine method. If push comes to shove I'll use that.
