title: Metal catalyst free cyclization of 3-alkynyl substituted 2-(indol-3-yl)quinoxalines in TFA alone: a new synthesis of indolophenazines.
abstract: TFA alone was found to be remarkably effective for the intramolecular hydroarylation (IMHA) of alkynes when employed as a solvent in the cyclization of 3-alkynyl substituted 2-(indol-3-yl)quinoxalines. This simple and metal free cyclization method afforded a range of indolophenazines as new and potential cytotoxic agents. The use of excess TFA was found to be crucial for the success of this reaction.
authors.affiliation: Department of Chemistry, Osmania University, Hyderabad-500 007, India. shivakumarkota@yahoo.co.in.
authors.forename: K Shiva
authors.initials: KS
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Osmania University, Hyderabad-500 007, India. shivakumarkota@yahoo.co.in.
authors.forename: Boyapally
authors.initials: B
authors.lastname: Bhaskar
authors.affiliation: Department of Chemistry, Osmania University, Hyderabad-500 007, India. shivakumarkota@yahoo.co.in.
authors.forename: Meesa Siddi
authors.initials: MS
authors.lastname: Ramulu
authors.affiliation: Department of Chemistry, Osmania University, Hyderabad-500 007, India. shivakumarkota@yahoo.co.in.
authors.forename: N Praveen
authors.initials: NP
authors.lastname: Kumar
authors.affiliation: Dr Reddy's Institute of Life Sciences, Hyderabad Central University, Campus, Gachibowli, Hyderabad-500 046, India. manojitpal@rediffmail.com.
authors.forename: Mohd Ashraf
authors.initials: MA
authors.lastname: Ashfaq
authors.affiliation: Dr Reddy's Institute of Life Sciences, Hyderabad Central University, Campus, Gachibowli, Hyderabad-500 046, India. manojitpal@rediffmail.com.
authors.forename: Manojit
authors.initials: M
authors.lastname: Pal
mesh_terms: D000480:Alkynes / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D010619:Phenazines / Q000138:chemical synthesis* / Q000737:chemistry; D011810:Quinoxalines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D007211:Indoles; D010619:Phenazines; D011810:Quinoxalines