Reactant is 5-amino-4-cyano-imidazole ring, tried so many methods but yet can't get any success.
I tried around 37 methods to get tetrazole but if u will draw the structure you will find the steric hindrance and resonance problem.i.e NH2 and CN are on the neighboring carbon and those carbon share a double bond that makes situation even worse.
Lone pair of NH2 then C=C and finally C triple bond N (i.e CN) comes such a order that cause a resonance between them. this means the carbon of cyano now become less electrophilic for the attack of the azide molecule.
Secondly its 5 membered ring system and has 2 endocyclic double bond which subsequently decrease the size and prevent the azide nuclephile to attack.
Heiko .....I am sorry to tell you that the method you told to me wont work out as i tried around 37 methods to get tetrazole but if u will draw the structure you will find the steric hindrance and resonance problem....i.e NH2 and CN are on the neighboring carbon and those carbon share a double bond that makes situation even worse.
Lone pair of NH2 then C=C and finally C triple bond N (i.e CN) comes such a order that cause a resonance between them. this means the carbon of cyano now become less electrophilic for the attack of the azide molecule.
Secondly its 5 membered ring system and has 2 endocyclic double bond which subsequently decrease the size and prevent the azide nuclephile to attack.
This is not the answer but further description of problem !!!
I tried around 37 methods to get tetrazole but if u will draw the structure you will find the steric hindrance and resonance problem....i.e NH2 and CN are on the neighboring carbon and those carbon share a double bond that makes situation even worse.
Lone pair of NH2 then C=C and finally C triple bond N (i.e CN) comes such a order that cause a resonance between them. this means the carbon of cyano now become less electrophilic for the attack of the azide molecule.
Secondly its 5 membered ring system and has 2 endocyclic double bond which subsequently decrease the size and prevent the azide nuclephile to attack.
Just guide lines to think of
From the above replies, it is clear that NH2 decreases the electrophilicity of the cyano carbon atom so I would start with nitro analogue then reduce it to target compound. I would also think about holding the effect of the nitrogen lone pair of the amino group by transforming the amino to imide then run the reaction and deprotect later [steric effect could occur !].
see
Tetrahedron Letters, Volume 50, Issue 31, 5 August 2009, Pages 4435-4438
Mahmoud Nasrollahzadeh, Yadollah Bayat, Davood Habibi, Saeed Moshaee
* By the way I did not see any 1,2 di substituents in their work !
Good luck
I agree with Abdel. My experience on tetrazole synthesis points towards that usually a more electron-defficient CN works better. So if you protect the NH2 with an electron withdrawing group it may work. Good luck
See The Chemistry of Enamines (S. F. Dyke) http://books.google.cz/books?id=wwo4AAAAIAAJ&printsec=frontcover&dq=Enamines&hl=cs&sa=X&ei=cVpgUpiELobTtAbm3IDoBA&redir_esc=y#v=onepage&q=Enamines&f=false
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