title: Multistep divergent synthesis of benzimidazole linked benzoxazole/benzothiazole via copper catalyzed domino annulation.
abstract: An efficient, facile synthesis of structurally diverse benzimidazole integrated benzoxazole and benzothiazoles has been developed. In a multi-step synthetic sequence, 4-fluoro-3-nitrobenzoic acid was converted into benzimidazole bis-heterocycles, via the intermediacy of benzimidazole linked ortho-chloro amines. The amphiphilic reactivity of this intermediate was designed to achieve the title compounds by the reaction of various acid chlorides and isothiocyanates in a single step through the in situ formation of ortho-chloro anilides and thioureas under microwave irradiation. A versatile one pot domino annulation reaction was developed to involve the reaction of benzimidazole linked ortho-chloro amines with acid chlorides and isothiocyanates. The initial acylation and urea formation followed by copper catalyzed intramolecular C-O and C-S cross coupling reactions furnished the angularly oriented bis-heterocycles which bear a close resemblance to the streptomyces antibiotic UK-1.
authors: Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300-10, Taiwan.
authors: Jen-Yu
authors: JY
authors: Liao
authors: Manikandan
authors: M
authors: Selvaraju
authors: Chih-Hau
authors: CH
authors: Chen
authors: Chung-Ming
authors: CM
authors: Sun
mesh_terms: D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D052160:Benzothiazoles / Q000737:chemistry*; D001583:Benzoxazoles / Q000737:chemistry*; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D003300:Copper / Q000737:chemistry*
chemical_list: D001562:Benzimidazoles; D052160:Benzothiazoles; D001583:Benzoxazoles; D003300:Copper; C031000:benzimidazole; C005465:benzothiazole