430429-44-0

Upstream product

• 36081-66-0 2'-bromo-2-phenylacetophenone 
• 2142-69-0 2-bromophenyl methyl ketone 
• 591-50-4 iodobenzene 
• 4001-73-4 2-Bromobenzamide 
• 2042-37-7 o-cyanobromobenzene 

Relevant academic research and scientific papers

Parecoxib sodium substituted impurity and preparation method thereof

The invention relates to a parecoxib sodium substituted impurity and a preparation method thereof. The preparation method comprises the following steps: carrying out a reaction on a compound with a structure represented by a formula I with hydroxylamine h

Conformational studies by dynamic NMR. 89. Stereomutation and cryogenic enantioseparation of conformational antipodes of hindered aryl oximes

Aryl benzyl oximes having the configuration Z give rise to stereolabile atropisomers when a halogen atom is present in the ortho position of the aryl moiety, as a consequence of the restricted aryl-CN bond rotation. By means of dynamic H NMR spectroscopy it has been possible to determine the corresponding rotation barrier, hence the lifetime of the atropisomers that, in the case of the iodine derivative, was found sufficiently long as to allow a physical separation to be achieved on an appropriately cooled enantioselective HPLC column. Comparison of the barriers determined by dynamic NMR and dynamic HPLC proved the equivalence of the two techniques. When the iodine atom was substituted by an α-naphthyl group, two dynamic processes were observed. That with the lower barrier could be determined by NMR and that with the higher barrier by HPLC, thus outlining the complementarity of these two techniques.