Rhizoctonia leguminicola swainsonine from

A trail pheromone of the Pharaoh ant was identified as 3-butyl-5-methylindolizidine of the stereochemistry given in (219) (75JHC289). Slaframine (220) is a metabolite isolated from Rhizoctonia leguminicola responsible for producing excessive salivation in cattle. A stereoselective synthesis was reported (73JOC3848). Swainsonine (221), a potent inhibitor of a-mannosidase, has been isolated from Swainsona caneszens. The stereochemistry was derived from the NMR spectrum (79AJC2257). 

The biosynthesis of swainsonine was studied in the fungus Rhizoctonia leguminicola The piperidine ring was shown to be derived from lysine via pipecolic acid. A noteworthy... 

Harris et al. postulated that (liS, 8aS)-( + )-l-hydroxyindolizidine (109) and (lf ,8aS)-l-hydroxyindolizidine (110) were pivotal intermediates in the biosynthesis of slafi-amine (3) and swainsonine (cf. Section lU.C) in the fungus Rhizoctonia leguminicola (74). Compound 110 was subsequently isolated as e acetate from extracts of the diablo locoweed. Astragalus oxyphysus (75). 

The biosynthesis of slaframine (38) and swainsonine (35) in Rhizoctonia leguminicola involves lysine and proceeds via the intermediacy of pipecolic acid. Carbon atoms 2 and 3 have been demonstrated to come from acetate via malonate (Fig. 30.14). The biosynthesis of swainsonine and related compounds in plants does not appear to have been investigated (Elbein and Molyneux, 1987 Harris et al, 1987 Howard and Michael, 1986). 

Synthesis of ( )-Swmnsonine ( )-Swainsonine is an indoUzidine alkaloid that is isolated from the fungus Rhizoctonia leguminicola and later it was found in the AustraUan plant Swainsona canescens It is famous for its lysosomal mannosidase inhibiting activity. ( )-Swainso-nine is also well known for its antineoplastic activity as it is... 

---