By Transformation of Imidazolone Derivatives

Electrophilic attack of the HN—C=X moiety in imidazolone derivatives at X (which has usually been sulfur) can result in 4//-imidazoles. This has been the most commonly used method for the preparation of these compounds. 

and several other products 8 likewise gave 17% each of 7 and the corresponding 3.  

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