74612-20-7Relevant academic research and scientific papers
Pyrrolizidine Alkaloids. Synthesis of 13,13-Dimethyl-1,2-didehydrocrotalanine
Robins, David J.,Sakdarat, Santi
, p. 282 - 283 (1980)
The first synthesis of an 11-membered macrocyclic pyrrolizidine diester has been achieved from (+)-retronicine and 3,3-dimethylglutaric anhydride.
Synthesis of Macrocyclic Dilactones by Cyclization of Sulfonium Salts
Nakamura, Takako,Matsuyama, Haruo,Kamigata, Nobumasa,Iyoda, Masahiko
, p. 3783 - 3789 (2007/10/02)
An efficient method for the formation of macrocyclic dilactones via cyclization of (ω-carboxyalkyl)diphenylsulfonium salts 3 containing an ester linkage under mild conditions is described.These sulfonium salts 3 were cyclized in the presence of cesium carbonate under high-dilution conditions to give 11- to 16-membered dilactones 4 in good yields.The cyclization of sulfonium salt 22 was successfully carried out for the synthesis of 11-membered dilactonic pyrrolizidine alkaloid, 13,13-dimethyl-1,2-didehydrocrotalanine 23.
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.
