Collect. Czech. Chem. Commun. 1980, 45, 956-965

Pseudobase formation in 2-methylpapaverinium cations and their biotransformation by enzymes of rat liver homogenates in vitro

Daniela Walterováa, Vladimír Preiningera, Ladislav Dolejšb, František Grambalc, Miroslav Kyselýa, Ivo Válkaa and Vilím Šimáneka

a Institute of Chemistry, Medical Faculty, Palacký University, 775 15 Olomouc
b Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6
c Institute of Inorganic and Physical Chemistry, Faculty of Natural Sciences, Palacký University, 771 00 Olomouc


2-Methylpapaverinium iodide (I), 2'-hydroxymethyl-2-methylpapaverinium iodide (IX), and 2-methyl-3,4-dihydropapaverinium iodide (X. CH3I) form pseudobase by addition of hydroxide ions to the C(1)=N(+) bond. 2'-Hydroxymethyl-2-methyl-3,4-dihydropapaverinium iodide (XV) and 2'-hydroxymethyl-2-methyl-9-oxo-3,4-dihydropapaverinium iodide (XVI) react with hydroxide ions in aqueous medium under formation of cyclic pseudobases XVII and XVIII. The equilibrium constants (KR+) of pseudobase formation have been measured in aqueous ethanol (1 : 1 w/w, 25°C, ionic strength 0.1). The quaternary papaverinium derivatives are metabolized to isoquinilones and carbonyl compounds by means of rat liver enzymes. The role of pseudobases in these biotransformations has been discussed and biogenetic conclusions have been drawn.