82296-59-1Relevant articles and documents
Pyrrolizidine Alkaloid Analoques. Synthesis of Eleven-membered Macrocyclic Diesters of Retronecine
Devlin, J. Alastair,Robins, David J.,Sakdarat, Santi
, p. 1117 - 1122 (2007/10/02)
Treatment of (+)-retronecine (1) with 3,3-disubstituted glutaric anhydride derivatives (2) yielded mixtures of the retronecine 7- and 9-monoesters, which were assayed by 1H n.m.r. spectrometry.Lactonisation of these mixtureswas achieved by the Corey-Nicolaou method to give a range of eleven-membered macrocyclic pyrrolizidine diesters (5) with different substituents at C-13.The macrocyclic nature of these pyrrolizidine alkaloid analogues was established by comparison of their 1H n.m.r. and mass spectra with those of natural pyrrolizidine alkaloids.