1H- und 13C-NMR.-spektroskopische Untersuchungen an den vier diastereomeren (±)-Dihydropalustraminsäure-methylestern; Strukturkorrelation mit (−)-Dihydropalustraminsäure-methylester sowie mit dem Alkaloid Palustrin. 14. Mitteilung über Schachtelhalmalkaloide

¹H-and¹³C-NMR. spectra of methyl esters of the diastereomeric (±)-dihydropalustramic acids; structural correlation of (?)-dihydropalustramic acid with the alkaloid palustrin Unambiguous assignment of cis-trans configuration at the piperidine ring of the four diastereomeric methyl esters of the (±)-dihydropalustramic acids is based on the interpretation of ¹H- and ¹³C-NMR. data. (?)-Dihydropalustramic acid, the important degradation product of the alkaloid palustrin is shown to be threo-cis-6-(1-hydroxypropyl)-2-piperidyl]acetic acid. The same conclusion holds for palustrin and dihydropalustrin. Therefore, palustrin is threo-cis-17-(1-hydroxy-propyl)-1,5,10-triazabicyclo11.4.0]heptadec-15-en-11-one.