Suzuki-type cross-coupling reaction of 1-benzyl-2-iodo-1H-benzimidazoles with aryl boronic acids: A regioselective route to N-alkylated 6-alkoxy-2-aryl-1H-benzimidazoles

Efficient Synthesis of Unsymmetrical Ureido‐Linked Disaccharides

“…Tetraacetyl-β-glucosyl azide 6, [23] was converted into the corresponding formamidic derivative 8 after hydrogenation and an in situ reaction with freshly prepared acetoformic anhydride. [24] The 1 H NMR spectrum shows that 8 was obtained as a pure β anomer but as a mixture of (E) and (Z) diastereoisomers, due to the iminic form of the formamido group. The 1 H NMR analysis is consistent with the literature data, [25] revealing a considerable prevalence of the (Z) isomer, which is evidenced by the presence of a singlet at δ ϭ 8.25 ppm [in the (E) isomer, the CHO signal at δ ϭ 8.21 ppm shows a doublet with J CHO,NH ϭ 10.…”

Current methods for the synthesis of 2-substituted azoles

“…Reactions of azole derivatives which take advantage of a boron-containing partner in the coupling reaction are also very common, but generally utilize a halogenated azole and marine alkaloids nortopsentins A-D. 162 Iodobenzimidazole 173 (Scheme 80) readily coupled with boronic acids, 163 including 2,6-dimethylaryl boronic acids, in good yield (75%) whereas a 3-nitrophenylboronic acid furnished the biaryl adduct in low (15%) yield.…”

Synthesis of Computationally Designed 2,5(6)-Benzimidazole Derivatives via Pd-Catalyzed Reactions for Potential E. coli DNA Gyrase B Inhibition

“…The limitations imposed by classic multi-step methods [ 16 , 17 ] on the functionalization of 5(6) position of benzimidazoles have driven our efforts towards the use of palladium-catalyzed coupling reactions, namely Suzuki-Miyaura and Buchwald-Hartwig. Current literature on this topic shows multiple reports of palladium-catalyzed reactions involving the oxidative addition to activated 2-halogen substituted benzimidazoles [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ], or 2-aminobenzimidazoles [ 27 ], however there are only a few examples describing their application for functionalization of the less reactive 5(6) position. These examples include Suzuki–Miyaura reactions [ 28 , 29 ] using vinyltrifluoroboronates or benzyltrifluoroborates as coupling agents, which, in general, do not include an appropriate hydrogen-bond acceptor according to our model, and/or require multi-step processes for their preparation.…”