A compound to which the reaction rule is not applicable.

User 9cc9c09363

16-01-2012 14:03:25

Hi.


I am facing a problem. I have one compound to which reaction rule is not applicable.


The reaction is called Criegee reaction which is the reaction of ozone with olefinic group to form ozonide.


Here I attached the file showing reactions. I tested 4 similar compounds.


You can see that only one compound, No. 1(Pyrimidine), is not reacting with ozone so the reactor only showed 3 results out of 4 reactants. 


I can't figure out why this reaction doesn't take place.


Please let me know.. what is the problem..

ChemAxon af8e24758b

17-01-2012 21:06:06

 


Hi,


The uracil derivative in your first example comes up as an aromatic ring due to Reactors' aromatization system, thus the scheme and the first example do not match anymore. 


I would recommend you modify the scheme, please find my suggestion below (ozonide-revised.jpg).  I changed the 'double bond' to a 'double-or-aromatic bond', I removed the R groups (they do not describe any special atoms or groups) and I also mapped all of the oxygens. 


I also would add the following reactivity rules to your reaction:


(match(ratom(1), "[C:1]=[C:2]", 1) 

and match(ratom(2), "[C:1]=[C:2]", 2))

or (match(ratom(1), "O=c1[c:1]([C,H])[c:2]([C,H])nc(=O)n1", 1)

and match(ratom(2), "O=c1[c:1]([C,H])[c:2]([C,H])nc(=O)n1", 2))

Nevertheless, you can remove O3 as a reactant from the scheme thus you do not need to add it as a reagent to each example, respectively. Your reaction will work properly. (ozonide-revision-2.jpg)


 


I hope the answers solve your problem!


User 9cc9c09363

19-01-2012 08:41:48

Hi.


Thank you for your answer and suggestion.


I made a mistake.. when I checked the original reference yesterday I found that there is another reaction before forming ozonide which is the formation of O3 adduct at C5. So I don't need to include aromatic bond in my reaction.


I kept making mistakes.:) It's obvious that the carbon with hydroxyl group for the other 3 compounds above has sp3 hydridization so conjugation system over the ring cannot be formed.


I should have been careful before I asked you. I am very sorry to bother you too much.


Once again thank you very much.