A new NBS/oxone promoted one pot cascade synthesis of 2-aminobenzimidazoles/2-aminobenzoxazoles: a facile approach. (11th August 2016)

• Record Type: Journal Article
• Authors: Daswani, Ujla; Dubey, Nitin; Sharma, Pratibha; Kumar, Ashok
• Is Part Of: New journal of chemistry. Volume 40:Number 9(2016:Sep.)
• Page Start: 8093
• Page End: 8099
• Publication Date: 2016-08-11
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c6nj00478d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A rapid and transition metal free synthesis of 2-aminobenzazoles using readily available substrates. Abstract : A new strategy for the synthesis of 2-aminobenzimidazoles via a reaction of α-halogenated cyclohexanone with guanidine is reported. It provides a facile N -bromosuccinimide (NBS) mediated transition metal free, sustainable path for the synthesis of 2-substituted azoles. NBS along with the oxone promotes in situ halogenation of cyclohexanone, which in turn, when allowed to react with guanidine, afforded 2-aminobenzimidazoles (2-ABI). This eco-friendly protocol provides a competent laboratory synthesis method associated with significant advantages such as greater selectivity, cost-efficiency, mild reaction conditions, absence of chromatographic purification, clean reaction profile, and a simple work-up procedure to furnish high yields. The structures of all the synthesized compounds were confirmed on the basis of IR, 1 H and 13 C NMR, mass spectrometry, and elemental analyses data. In addition, we have also extended the scope of this strategy for obtaining 2-amino substituted benzoxazoles.