Synthesis of new macrocycles. Part 6. Pyridine-retronecate, a new synthetic alkaloid

Synthesis of new macrocycles. Part 6. Pyridine-retronecate, a new synthetic alkaloid Semisynthetic pyrrolizidine alkaloid antitumor agents Pyrrolizidine alkaloid biosynthesis. Synthesis of N-([4-14C]-4-aminobutyl)-1,2-didehydropyrrolidinium and its incorporation into different pyrrolizidine bases (necines) Macrocyclic Pyrrolizidine Alkaloids from Senecio anonymus. Separation of a Complex Alkaloid Extract Using Droplet Counter-Current Chromatography Ehretinine, a novel pyrrolizidine alkaloid from Ehretia aspera Novel pyrrolizidine alkaloid from Crotalaria nana Pyrrolizidine alkaloid analogues. Synthesis of 10-membered macrocyclic diesters of (±)-synthanecine A. X-Ray molecular structure of (±)-6,7-O,O-(succinyl)synthanecine A Simple procedures for preparing putative toxic metabolites of pyrrolizidine alkaloids Application of 2H n.m.r. spectroscopy to study the incorporation of enantiomeric [2-2H]-labelled putrescines into the pyrrolizidine alkaloid retrorsine Pyrrolizidine alkaloid analogues. Synthesis of macrocyclic diesters of (±)-synthanecine A from (±)-3-chloromethyl-2-hydroxymethyl-1-methyl-2,5-dihydropyrrolium chloride