Biosynthesis and metabolism of some matrine alkaloids inGoebelia pachycarpa

A Pyridine Dearomatization Approach to the Matrine-Type Lupin Alkaloids

“…with the pendant aldehyde is proposed to generate the oxidized tetracycle 9, which upon reduction gives (+)matridine (10). Seminal studies by Abdusalamov demonstrated that feeding 14 C-labeled (+)-10 to Goebelia Pachycarpa resulted in the isolation of (+)-2 with 14 C label at C15, suggesting that the final step in the biosynthesis of 2 is a site-selective C-H oxidation.…”

“…Seminal studies by Abdusalamov demonstrated that feeding 14 C-labeled (+)-10 to Goebelia Pachycarpa resulted in the isolation of (+)-2 with 14 C label at C15, suggesting that the final step in the biosynthesis of 2 is a site-selective C-H oxidation. 10,11 Synthetically, most of the prior work has focused on (+)-matrine (2), with four reported total syntheses. 12,13,14,15 Synthetic access to the minor congeners is far more limited, with a single total synthesis each of (+)allomatrine ( 3) and (+)-isosophoridine (5), and no completed total syntheses of (+)-isomatrine (1) or (-)sophoridine (4).…”

“…Although the detailed enzymatic pathway has not been fully annotated, the biosynthesis of matrine is proposed to initiate with the enzymatic conversion of (−)-lysine ( 6 ) to Δ 1 -piperidine ( 7 ) (Figure B). , Subsequent dimerization of 7 followed by oxidation and isomerization is proposed to yield quinolizidine 8 , a shared biosynthetic precursor to several lupin alkaloids. , Mannich addition of 8 to a third equivalent of 7 and cyclization with the pendant aldehyde is proposed to generate the oxidized tetracycle 9 , which upon reduction gives (+)-matridine ( 10 ). Seminal studies by Abdusalamov demonstrated that feeding 14 C-labeled (+)- 10 to Goebelia Pachycarpa resulted in the isolation of radio-labeled (+)- 2 , suggesting that the final step in the biosynthesis of 2 is a site-selective C–H oxidation. , …”