[The degradation mechanism of penequine hydrochloride in aqueous solutions]

Penequine hydrochloride (I) is a new potent anticholinergic drug, the degradation mechanism of I in aqueous solutions is reported in this paper. I is an ethereal compound, stable in neutral and alkaline solutions, but it decomposes in strong acidic solutions. Its main degradation products have been separated and identified by means of TLC, MS, GC/MS and GC/FTIR. With reference to the general degradation rule of ethereal compound and the structure of the degradation products, we deduced that the ether linkage of I splits in acidic solutions by the catalysis of hydrogen ion, producing 3-quinuclidinol (DP1) and 1-phenyl-1-cyclopentyl glycol. The latter turns into 1-phenyl-1-cyclopentyl acetaldehyde through dehydration and rearrangement. In addition, small amounts of other degradation compounds, e. g. benzaldehyde, acetophenone, phenylcyciopentyl ketone, etc. have also been found, but the mechanism remains to be further studied.