Categories: Synthesis of N-Heterocycles > benzo-fused N-Heterocycles >
Synthesis of benzimidazolones
Recent Literature
Intramolecular N-arylations of ureas to form benzimidazol-2-ones occur in the
presence of KOH and DMSO at close to ambient temperature. Under these conditions
the yields are high and a wide range of functional groups are tolerated.
A. Beyer, C. M. M. Reucher, C. Bolm, Org. Lett., 2011,
13, 2876-2879.
CuI/l-proline catalyzed coupling of aqueous ammonia with 2-iodoacetanilides and
2-iodophenylcarbamates affords aryl amination products at room temperature,
which undergo in situ additive cyclization under acidic conditions or heating to
give substituted 1H-benzimidazoles and 1,3-dihydrobenzimidazol-2-ones,
respectively.
X. Diao, Y. Wang, Y. Jiang, D. Ma, J. Org. Chem., 2009,
74, 7974-7977.
The combination of Ph3P and I2 promotes a synthesis of
benzimidazolones from readily accessible hydroxamic acids. Upon Lossen-type
rearrangement of the O-activated hydroxamic acids, the in situ generated
isocyanates undergo an intramolecular attack by ortho N-nucleophiles
producing the cyclized products in good yields under mild conditions.
N. Wiriya, D. Yamano, S. Hongsibsong, M. Pattarawarapan, W. Phakhodee, Synlett, 2022,
33,
1468-1472.
A metal-free synthesis of 1-arylbenzimidazol-2-ones from of N-aryl-2-nitrosoanilines
can be carried out under mild conditions using solid carbon dioxide as a source
of the key carbonyl moiety. The atom economy of the synthesis of the starting
materials makes the entire synthesis of the target compounds environmentally
friendly.
E. Łukasik, Z. Wróbel,
Synthesis, 2016, 48, 1159-1166.
An oxidation of imidazolinium, imidazolium and benzimidazolium derivatives in the presence
of copper and air provides imidazolidinones, imidazolones, and benzimidazolones
in good yields under mild conditions. Low yields were obtained with sterically
hindered substrates.
D. Li, T. Ollevier,
Org. Lett., 2019, 21, 3572-3575.
High-yielding reductive alkylation of electron-deficient o-haloarylamines
followed by treatment with inexpensive N-chlorosulfonyl isocyanate
afforded primary ureas in good overall yields. A Pd-catalyzed urea
cyclization reaction furnished imidazopyridinones and benzoimidazolones in
excellent yields.
M. McLaughlin, M. Palucki, I. W. Davies, Org. Lett.,
2006, 8, 3311-3314.
2-phenoxycarbonyl-4,5-dichloropyridazin-3(2H)-one is a solid stable
carbonyl source that is a recyclable. The reagent enables the synthesis of
benzo[d]thiazol-2(3H)-ones, benzo[d]oxazol-2(3H)-ones, and
benzo[d]imidazol-2(3H)-ones using in one pot out under neutral or
acidic conditions to give the corresponding heterocycles in very good yields.
K. E. Ryu, B. R. Kim, G. H. Sung, H. J. Yoon, Y.-J. Yoon,
Synlett, 2015, 26, 1985-1990.
In a direct method for the regioselective construction of benzimidazolones, a
single palladium catalyst couples monosubstituted urea substrates with
differentially substituted 1,2-dihaloaromatic systems via a cascade of two
discrete and highly chemoselective C-N bond-forming processes. The method allows
a predictable formation of complex heterocycles from simple, readily available
starting materials.
J. B. Ernst, N. E. S. Tay, N. T. Jui, S. L. Buchwald, Org. Lett., 2014,
16, 3844-3845.