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2005
Imidazole derivatives
R 0190
Heterocyclization of Functionalized Heterocumulenes with C,N- and C,O-BiPart 5. Synthesis of Imidazo[1,5-a]imidazole Derivatives by Cyclo21- 130 nucleophiles.
condensation of 1-Chloroalkyl Isocyanates with Imidazoles and Benzimidazole.
— The reactions of 1-chloroalkyl isocyanates (II) with imidazoles and benzimidazoles
(I) afford the corresponding imidazo imidazole derivatives (III) in yields between 8 and
81%. It is established that the yields of the target products depend mainly on the structure of the imidazole used. For instance, isocyanates react with unsubstituted imidazole
(Ia) and phenylimidazole (Ib) when heating in benzene in the presence of triethylamine
in 55-81 % yield. Benzimidazoles like (Ie) and (If) require heating in toluene and disubstituted imidazoles (Ic) and (Id) undergo cyclization in 8—37% only after prolonged boiling in p-xylene. — (VOVK, M. V.; SUKACH, V. A.; PINCHUK, A. M.;
CHERNEGA, A. N.; PIROZHENKO, V. V.; HOWARD, J. A. K.; Russ. J. Org. Chem.
40 (2004) 11, 1638-1643; Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094,
Ukraine; Eng.) — Bartels
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