SATURATED PYRROLIZIDINEDIOLS .I. SPECTRAL STUDIES AND CONVERSION OF AN ESTER OF DIHYDROXYHELIOTRIDANE INTO (+) ENANTIOMER OF HASTANECINE

The mass and nuclear magnetic resonance spectra of the saturated pyrrolizidinediols and their parent alkaloids show that hastanecine and the amino alcohol from retusine are 7-hydroxy-1-hydroxymethyl derivatives and macronecine is a 2-hydroxy-1-hydroxymethyl derivative, probably 2β-hydroxy-1β-hydroxymethyl-8β-pyrrolizidine. The relative and absolute stereochemistry of hastanecine is established as 7β-hydroxy-1β-hydroxymethyl-8β-pyrrolizidine by the preparation of its enantiomer from an ester of dihydroxyheliotridane by changing the configuration at C-l. The amino alcohol from retusine is identical with tumeforcidine. © 1969, American Chemical Society. All rights reserved.