title: Studies on the role of tetrazole in the activation of phosphoramidites.
abstract: The mechanism of the tetrazole-activated coupling step in the synthesis of oligonucleotides via phosphoramidites is studied with the help of model reactions: Treatment of diethoxydiisopropylaminophosphane with two equivalents of tetrazole resulted in a diethoxy-tetrazolophosphane, whose (31P)-NMR shift of 126 ppm is identical with the signal observed during internucleotide bond formation. A series of different related diethoxy-phosphorous-acid derivatives were also synthesized; their (31P)-NMR signals between 123.9 and 130.8 ppm are additional evidence for the intermediacy of a tetrazolide species. Further NMR investigations with more basic azoles showed that tetrazole is also active as a proton donor.
authors.affiliation: Universität Ulm, Sektion Polymere, FRG.
authors.forename: S
authors.initials: S
authors.lastname: Berner
authors.forename: K
authors.initials: K
authors.lastname: Mühlegger
authors.forename: H
authors.initials: H
authors.lastname: Seliger
mesh_terms: D000577:Amides; D001393:Azoles; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009841:Oligonucleotides / Q000138:chemical synthesis*; D009943:Organophosphorus Compounds / Q000138:chemical synthesis; D010756:Phosphoric Acids; D013329:Structure-Activity Relationship; D013777:Tetrazoles
chemical_list: D000577:Amides; D001393:Azoles; D009841:Oligonucleotides; D009943:Organophosphorus Compounds; D010756:Phosphoric Acids; D013777:Tetrazoles; C045574:1H-tetrazole; C011067:phosphoramidic acid