Editing Imidazole (section)

===Formation from other heterocycles===
Imidazole can be synthesized by the [[photolysis]] of [[tetrazole|1-vinyltetrazole]]. This reaction will give substantial yields only if the 1-vinyltetrazole is made efficiently from an [[organotin compound]], such as 2-tributylstannyltetrazole. The reaction, shown below, produces imidazole when R<sub>1</sub> = R<sub>2</sub> = R<sub>3</sub> = hydrogen.
:[[File:Imidazole_synthesis_from_vinyltetrazole.svg|none|500px]]
Imidazole can also be formed in a vapor-phase reaction. The reaction occurs with [[formamide]], [[ethylenediamine]], and hydrogen over [[platinum]] on [[alumina]], and it must take place between 340 and 480&nbsp;°C. This forms a very pure imidazole product.

The [[Van Leusen reaction]] can also be employed to form imidazoles starting from [[TosMIC]] and an [[aldimine]].<ref>{{cite journal|last1=Van Leusen|first1=Albert M.|last2=Wildeman|first2=Jurjen|last3=Oldenziel|first3=Otto H.|date=1977|title=Chemistry of sulfonylmethyl isocyanides. 12. Base-induced cycloaddition of sulfonylmethyl isocyanides to carbon, nitrogen double bonds. Synthesis of 1,5-disubstituted and 1,4,5-trisubstituted imidazoles from aldimines and imidoyl chlorides|journal=Journal of Organic Chemistry|volume=42|issue=7|pages=1153–1159|doi=10.1021/jo00427a012|bibcode=1977JOrgC..42.1153A}}</ref> The Van Leusen Imidazole Synthesis allows the preparation of imidazoles from aldimines by reaction with tosylmethyl isocyanide (TosMIC). The reaction has later been expanded to a two-step synthesis in which the aldimine is generated in situ: the Van Leusen Three-Component Reaction (vL-3CR).