title: OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles.
abstract: OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA. baskar@okstate.edu.
authors.forename: Baskar
authors.initials: B
authors.lastname: Nammalwar
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA. npiict@gmail.com.
authors.forename: Nagendra Prasad
authors.initials: NP
authors.lastname: Muddala
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA. raja2765@yahoo.com.
authors.forename: Rajasekar
authors.initials: R
authors.lastname: Pitchimani
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA. rab@okstate.edu.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bunce
mesh_terms: D001386:Azides / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D002384:Catalysis; D057930:Click Chemistry / Q000379:methods; D008670:Metals / Q000737:chemistry*; D058608:Nanopores; D009570:Nitriles / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013777:Tetrazoles / Q000737:chemistry*
chemical_list: D001386:Azides; D017610:Calcium Compounds; C509968:MCM-41; D008670:Metals; D009570:Nitriles; D017640:Silicates; D013777:Tetrazoles; C045574:1H-tetrazole; D012822:Silicon Dioxide; C031293:calcium silicate
keywords: 5-benzyl and 5-aryl-1H-tetrazoles; carboxylic acid bioisosteres; click 1,3-dipolar addition; heterogeneous catalysis; recyclable catalyst