title: The stability of N-[2-(4-o-fluorophenylpiperazin-1-yl)ethyl]-2,5-dimethyl-1 -phenylpyrrole-3,4-dicarboximide in aqueous-organic solutions.
abstract: The first-order reaction of solvolysis of N-[2-(4-o-fluorophenylpiperazin-1-yl)ethyl]-2,5-dimethyl-1-phenylpyrrole-3,4-dicarboximide (PDI) was investigated as a function of pH at 333, 328, 323, 318 and 308 K in the pH range 1.11 - 12.78. The decomposition of PDI was followed by the HPLC method (Nucleosil 10-C8 column (250 x 4 mm I.D., dp = 10 microm), mobile phase: 0.018 mol/L ammonia acetate - acetonitrile (40: 60 v/v), UV detector: 240 nm, flow rate: 1 mL/min. Specific acid-base catalysis involves solvolysis of the undissociated molecules of PDI catalyzed by hydroxide ions and spontaneous solvolysis of the undissociated and monoprotonated forms of PDI under the influence of solvents. The thermodynamic parameters of the reactions--activation energy (E(a)), enthalpy (DH(#)), entropy (DS(#))--were calculated.
authors.affiliation: Department of Pharmaceutical Chemistry, Poznań University of Medical Sciences, Grunwaldzka 6, 60-780 Poznań, Poland.
authors.forename: Marianna
authors.initials: M
authors.lastname: Zajac
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Sobczak
authors.forename: Wiesław
authors.initials: W
authors.lastname: Malinka
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Redzicka
mesh_terms: D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry*; D010879:Piperazines / Q000138:chemical synthesis / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D000577:Amides; D006878:Hydroxides; C548176:N-(2-(4-o-fluorophenylpiperazin-1-yl)ethyl)-2,5-dimethyl-1 -phenylpyrrole-3,4-dicarboximide; D009930:Organic Chemicals; D010879:Piperazines; D011758:Pyrroles; D012997:Solvents; D014867:Water; C031356:hydroxide ion