title: Cooperative catalysis by bovine serum albumin-iodine towards cascade oxidative coupling-C(sp(2))-H sulfenylation of indoles/hydroxyaryls with thiophenols on water.
abstract: Cooperative cascade catalysis by bovine serum albumin (BSA)-iodine allows for the first time the performance of C(sp(2))-H sulfenylation of indole from readily available thiophenol (-SH bond) via in situ generation/cleavage of disulfide (S-S bond) in air under aqueous conditions, whereas BSA or I2 individually do not permit this two step sequence to occur in the same pot towards C-S bond formation. This green cooperative protocol is extendable to sulfenylation of hydroxyaryls (i.e. 2-naphthol or 4-hydroxycoumarin) with diverse thiols (aryl/heteroaryl) without using any toxic metal catalysts, bases or oxidants, thus rendering the process environmentally and economically reliable. Further, the gram scale synthesis of a COX-2 inhibitor (3-(pyridin-2-ylthio)-1H-indole), regioselectivity and recyclability (up to four cycles) are the additional merits of this cooperative cascade bio-chemocatalytic (BSA-I2) protocol. Moreover, HPLC and ESI-MS provide powerful insights into the mechanistic aspects of the above cascade sulfenylation reaction.
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India. aksinha08@rediffmail.com ak.sinha@cdri.res.in and Academy of Scientific and Innovative Research (AcSIR), New Delhi, India.
authors.lastname: Saima
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India. aksinha08@rediffmail.com ak.sinha@cdri.res.in.
authors.forename: Danish
authors.initials: D
authors.lastname: Equbal
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India. aksinha08@rediffmail.com ak.sinha@cdri.res.in.
authors.forename: Aditya G
authors.initials: AG
authors.lastname: Lavekar
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India. aksinha08@rediffmail.com ak.sinha@cdri.res.in and Academy of Scientific and Innovative Research (AcSIR), New Delhi, India.
authors.forename: Arun K
authors.initials: AK
authors.lastname: Sinha
mesh_terms: D000818:Animals; D002384:Catalysis; D002417:Cattle; D004220:Disulfides / Q000138:chemical synthesis* / Q000737:chemistry; D007211:Indoles / Q000737:chemistry*; D007455:Iodine / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D004220:Disulfides; D007211:Indoles; D010636:Phenols; D013438:Sulfhydryl Compounds; D014867:Water; D012710:Serum Albumin, Bovine; C042983:thiophenol; D007455:Iodine