The castanospermine derivativecelgosivir is an antiviral drug candidate currently in development for possible use in treating hepatitis C virus (HCV) infection.[6]
In the alternate pathway L-Lys cyclizes and forms the enamine, which reduces to L-pipecolic acid.
HSCoA and then malonyl-CoA react in a Claisen reaction with L-pipecolic acid to form SCoA ester which undergoes a ring closure to form 1-indolizidinone. The carbonyl on 1-indolizidinone is reduced to the hydroxyl group. The molecule is then further hydroxylated to form the final product castanospermine.[10]
^Hohenschutz, Liza D.; Bell, E. Arthur; Jewess, Phillip J.; Leworthy, David P.; Pryce, Robert J.; Arnold, Edward; Clardy, Jon (1981). "Castanospermine, a 1,6,7,8-tetrahydroxyoctahydroindolizine alkaloid, from seeds of Castanospermum australe". Phytochemistry. 20 (4): 811–14. Bibcode:1981PChem..20..811H. doi:10.1016/0031-9422(81)85181-3.
^Durantel, D. (2009). "Celgosivir, an alpha-glucosidase I inhibitor for the potential treatment of HCV infection". Current Opinion in Investigational Drugs. 10 (8): 860–70. PMID19649930.
^Walsh, Christopher (2017). Natural Product Biosynthesis: Chemical Logic and Enzymatic Machinery. Royal Society of Chemistry. p. 270. ISBN978-1788010764.
^Dewick, Paul (2009). Medicinal Natural Products A Biosynthetic Approach. United Kingdom: Wiley. p. 330. ISBN978-0-470-74167-2.