1222313-87-2Relevant academic research and scientific papers
Resolution of 5-oxo-1-phenylpyrazolidine-3-carboxylic acid and synthesis of novel enantiopure amide derivatives
Melgar-Fernandez, Roberto,Gonzalez-Olvera, Rodrigo,Vargas-Caporali, Jorge,Perez-Isidoro, Rosendo,Juaristi, Eusebio
experimental part, p. 55 - 75 (2010/09/03)
The synthesis is reported of (±)-5-oxo-1-phenylpyrazolidine-3- carboxylic acid, (±)-3, via nucleophilic addition of phenylhydrazine to dimethyl maleate, followed by cyclization of the resulting hydrazine-diester. The resolution of (±)-3 was achieved via diastereomeric salts employing (R)- and (S)-a-methylbenzylamine as resolving agent. Preferential crystallization of the like (R,R)- and (S,S)- salts allowed the isolation of the desired enantiomerically pure (R)- and (S)- target compounds in up to 87-89 % of the theoretical yield. An X-ray structure of the (S,S)- salt allowed secure assignment of its relative configuration, and thus unequivocal assignment of the absolute configuration in the enantiomeric heterocycles.
