1126476-85-4

Upstream product

• 1222313-75-8 (R)-1-phenylethylammonium (R)-5-oxo-1-phenylpyrazolidine-3-carboxylate 
• 1126476-77-4 (R)-tert-butyl-5-((S)-1-methoxy-3-methyl-1-oxobutan-2-ylcarbamoyl)-3-oxo-2-phenylpyrazolidine-1-carboxylate 

Downstream Products

• 1222313-87-2 (R)-methyl 5-oxo-1-phenylpyrazolidine-3-carboxylate 

Relevant academic research and scientific papers

Resolution of 5-oxo-1-phenylpyrazolidine-3-carboxylic acid and synthesis of novel enantiopure amide derivatives

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.

Optical resolution of 5-oxo-1-phenyl-pyrazolidine-3-carboxylic acid as a new organocatalyst for organic reactions

Optical resolution of racemic 5-oxo-1-phenyl-pyrazolidine-3-carboxylic acid 2 with L-amino acid methyl ester via the diastereomers formation was investigated. Treatment of racemic 5-oxo-1-phenylpyrazolidine-3-carboxylic acid 2 with L-valine methyl ester g