A convenient oxidative cyclodesulfurization method toward the synthesis of benzofused nitrogen heterocycles using inexpensive and readily available potassium periodate as an oxidant was developed. Upon treating isothiocyanates with ortho-substituted anilines bearing N,N-, N,O-, and N,S-bis-nucleophiles, followed by an intramolecular cyclization of the in situ generated monothioureas, substituted 2-aminobenzazole
A sonochemical method for the synthesis of 2-aminobenzimidazoles and 2-aminobenzoxazoles, as well as chiral aminooxazolines and a chiral substituted quinazolin-5-one is reported. Using the Ph3P–I2 system in the presence of triethylamine as a desulfurization agent, monothioureas prepared in situ from the reaction of bis-nucleophiles with isothiocyanates underwent rapid cyclization to afford a variety
Desulfurization Mediated by Hypervalent Iodine(III): A Novel Strategy for the Construction of Heterocycles
作者:Harisadhan Ghosh、Ramesh Yella、Jayashree Nath、Bhisma K. Patel
DOI:10.1002/ejoc.200800901
日期:2008.12
The desulfurization ability of diacetoxyiodobenzene (DIB) has been explored in the preparation of isothiocyanates from the corresponding dithiocarbamate salts. The in situ generated isothiocyanates reacted with o-phenylenediamine and o-aminophenol to form monothioureas, which, on treatment with a further equivalent of DIB in one pot, gave benzimidazoles and aminobenzoxazoles, respectively. Aliphatic
Copper-Promoted One-Pot Approach: Synthesis of Benzimidazoles
作者:S. N. Murthy Boddapati、Ramana Tamminana、Ravi Kumar Gollapudi、Sharmila Nurbasha、Mohamed E. Assal、Osamah Alduhaish、Mohammed Rafiq H. Siddiqui、Hari Babu Bollikolla、Syed Farooq Adil
DOI:10.3390/molecules25081788
日期:——
first time on a copper catalyst promoted domino C–N cross-coupling reaction for the generation of 2-arylaminobenzimidazoles. Mechanistic investigations revealed that the synthetic pathway involves a copper-based desulphurization/nucleophilicsubstitution and a subsequent domino intra and intermolecular C–N cross-coupling reactions. Some of the issues typically encountered during the synthesis of 2
Nickel-catalyzed Chan–Lam cross-coupling: chemoselective N-arylation of 2-aminobenzimidazoles
作者:K. Anil Kumar、Prakash Kannaboina、D. Nageswar Rao、Parthasarathi Das
DOI:10.1039/c6ob01307d
日期:——
A complementary set of Ni- and Cu-based catalyst systems for the selective N-arylation of 2-aminobenzimidazoles have been developed. Selective N-arylation of the primary amine (C-NH2) group was achieved by Ni-catalyzed, boronic acid promoted cross-coupling reactions in air, whereas, selective N-arylation of the azole nitrogen was achieved with Cu-catalysis and aryl halides. These protocols are general