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Solvent‐Dependent Oxime–Azide and Oxime–Nitrile Coupling: Crystallographic and Catalytic Studies
Author(s) -
Dolai Malay,
Mistri Tarun,
Biswas Surajit,
Rogez Guillaume,
Ali Mahammad
Publication year - 2014
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201402178
Subject(s) - chemistry , oxime , triethylamine , tetrazole , azide , nitrile , sodium azide , catalysis , solvent , ligand (biochemistry) , crystal structure , medicinal chemistry , crystallography , photochemistry , stereochemistry , organic chemistry , biochemistry , receptor
This study describes the solvent‐dependent conversion of an oxime under identical reaction conditions ([Cu(bipy)Cl 2 ]/NaN 3 /5‐Br‐H 2 salox/TEA=1:2:1:2 molar ratio; bipy=2,2′‐bipyridyl, 5‐Br‐H 2 salox=5‐bromosalicylaldoxime, TEA=triethylamine), but in different solvents. In DMSO/CH 2 Cl 2 (2:1 v/v) only tetrazole is formed, whereas iminoacylation in MeCN and simple complexation takes place in MeOH. The formed tetrazole and iminoacylated ligands further undergo complexation with metal ions, as evidenced from single‐crystal X‐ray diffraction studies and ESI‐MS analyses. Mechanistic models have been proposed in which coordination‐assisted bonding of sodium azide across the CNOH double bond occurs to form a tetrazole and oxime–MeCN coupling forms an iminoacylated ligand. The former is a catalytic reaction, as evidenced from a turnover number of approximately 50, whereas the latter is stoichiometric in nature. This is the first report to demonstrate the dependence of solvent polarity on oxime transformation reactions through structural elucidation.