567-39-5Relevant academic research and scientific papers
Macrocyclic Pyrrolizidine Alkaloids. Synthesis and Stereochemistry of (+)-Dicrotaline (13β-Hydroxy-13α-methyl-1,2-didehydrocrotalanine) and (+)-13-epi-Dicrotaline
Brown, Kenneth,Devlin, J. Alastair,Robins, David J.
, p. 1819 - 1824 (2007/10/02)
Treatment of (+)-retronecine (1) with the trimethylsilyl ether of 3-hydroxy-3-methylglutaric anhydride gave a mixture of the 7- and 9-monoesters of (+)-retronecine (1).Lactonisation of this mixture was achieved using the corresponding pyridine-2-thiol esters to give (+)-dicrotaline (13β-hydroxy-13α-methyl-1,2-didehydrocrotalanine) (2) and (+)-13-epi-dicrotaline (3).The absolute configuration at C-13 in both compounds was established by a sequence of selective reactions on each epimer to yield optically active mevalonolactone.
EHRETININE, A NOVEL PYRROLIZIDINE ALKALOID FROM EHRETIA ASPERA
Suri, Om P.,Jamwal, Rajinder S.,Suri, Krishan A.,Atal, Chand K.
, p. 1273 - 1274 (2007/10/02)
The structure for ehretinine, 7-O-(p-methoxybenzoyl)-retronecanol, a new pyrrolizidine alkaloid isolated from leaves of Ehretia aspera has been established by a combination of spectroscopic and chemical methods.To our knowledge this constitutes the first report of the natural occurence of a retronecanol ester.Key Word Index -- Ehretia aspera; Boraginaceae; pyrrolizidine; retronecanol; p-methoxybenzoic acid.
