485-71-2, Cinchonidine is a catalyst-ligand compound, ?involved in a variety of chemical synthesis. Rlated chemical reaction is continuously updated,485-71-2
Resolution of the enantiomers of 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-pyrazole-3-carboxylic acid The resolution of the enantiomers of 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-pyrazole-3-carboxylic acid was carried out via reaction with the following chiral bases: BrucineQuinine(-)-Cinchonidine(+)-CinchonineR-(+)-1-Phenylethylamine(1 R,2S)-(-)-Ephedrine hydrochloride(1S,2R)-(+)-Ephedrine hydrochloride. In each case the reactions were carried out with 0.5 and 1 equivalents of base in respect to 1 equivalent of the acid compound and by using the following solvents EthanolAcetoneAcetonitrilDioxaneEthylacetateChloroform. The results are summarized in the following tables. It may be understood that the afore mentioned crystallisation experiments that are not reflected in the following tables did not yield crystals of the respective salts under the given conditions. However, suitable conditions for crystallization of these salts can be determined by those skilled in the art via routine experiments. In the following tables Acid represents racemic 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-pyrazo)e-3-carboxylic acid R-Acid represents the respective derivative of (R)-5-( 4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-pyrazole-3-carboxylic acid S-Acid represents the respective derivative of (S)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4,5-dihydro-pyrazole-3-carboxylic acidProcesses for crystallisation: Process A: A solution of the chiral base was added on top of a solution of the racemic acid at room temperature.Process C: A solution of the racemic acid was added on top of a solution of the chiral base. The mixture was heated to reflux and solvent was added until dissolution was complete. The solution was left to crystallisation at r.t.Process D: The chiral base was directly added on top of a solution of the racemic acid at room temperature.Process E: The chiral base was directly added on top of a solution of the racemic acid at reflux temperature.Process F: The solution of the salt was evaporated to dryness. The residue was dissolved in a minimum amount of the solvent under reflux heating. The solution was left to crystallisation at r.t.Resolution with (-)-Cinchonidine [Show Image] Acid g (mmol) Eq. amine Proc. Solvent for crystallisation T CrystYield 1st Cryst. % % S-Acid % R-Acid0,4 g (1,09 mmol) 1 F 2ml dioxane r.t 31 94,4 5,60,4 g (1,09 mmol) 1 F 19ml Ethylacetate r.t 28,5 95,8 4,20,4 g (1,09 mmol) 1 F 20ml acetone r.t. 19,6 96,9 3,10,4 g (1,09 mmol) 1 F 24ml acetonitrile r.t 42 85,8 14,1
The synthetic route of 485-71-2 has been constantly updated, and we look forward to future research findings.
Reference£º
Patent; Laboratorios del Dr. Esteve S.A.; EP1944293; (2008); A1;,
Metal catalyst and ligand design
Ligand Template Strategies for Catalyst Encapsulation – NCBI