113290-06-5Relevant academic research and scientific papers
Azoles. Part 7. A Convenient Synthesis of Thienoimidazoles
Iddon, Brian,Khan, Nazir,Lim, Bee Lan
, p. 1457 - 1464 (2007/10/02)
A number of 1-mono- and 1,2-di-protected 4-bromoimidazole-5-carbaldehydes, (7), (8), (11), and (13)-(15), reacted with ethyl thioglycollate in ethanol in the presence of sodium ethoxide to give the corresponding title compound, (16), (17), or (19)-(22), respectively (65-70percent yield).Shorter reaction times allowed intermediates to be isolated, e.g. (13) gave (20) (69percent) and (23) (12percent).Several attempts to obtain the parent system, 1H- or 3H-thienoimidazole, failed.Attempts to prepare the title compounds from imidazoles by several classical syntheses used for annelated thiophene systems (due to Tilak, Campaigne, and Krollpfeiffer) failed as did attempts to prepare imidazolethiols through chlorosulphonation or thiocyanation of imidazoles or via their reaction with 2,4-dinitrobenzenesulphenyl chloride.Several unsuccesful approaches to the title compounds from thiophenes are also described.
