13a -Hydroxymultiflorine

Lupinus termis and related species accumulate a group of alkaloids possessing an unusual carbon skeleton, albine-type bases. In L. termis, (-)-albine (88) co-existed with (-)-multifloriiie (56), (-)-13a-hydroxymultiflorine (82) and (-)-ll,12-seco-12,13-didehydromultiflorine (83). The hypothetical biosynthetic mechanism is proposed to explain the substitution pattern of the propenyl side chain of 88 in relation to the coexistence of 82 and 83 (Fig. 8). In this proposed pathway, aza-Cope rearrangement is involved as the key step for formation of the allylic side chain at the unusual position, C-13. 83 can also be derived from the same pathway of biosyntliesis (84 83). This... 

Scheme 6. Biosynthesis of the quinolizidine alkaloids (+ )-4-coumaroylepilupinine and (-)-13a-tigloyloxymultiflorine. Molecular clones have been isolated for the enzymes shown. Abbreviations ECT,/7-coumaroyl-coenzymeA ( + )-epilupinine 0-/ -coumaroyltransferase HMT/HLT, tigloyl-coenzymeA (-)-13a-hydroxymultiflorine/( +)-13a-hydroxylupanine 0-tigloyltransferase LDC, lysine decarboxylase.

N-methylalbine), 17-oxolupanine, 13a-hydroxymultiflorine, and different esters of 13-hydroxylupanine such as 13-propyloxylupanine, 13-isobutyryloxylupanine, 13-butyryloxy lupanine, 13-isovaleroyloxylupanine, 13-angeloyloxylupanine,... 

Three new tetracyclic lupine alkaloids were isolated from Lupinus species and characterised (-)-13p-hydroxymultiflorine was isolated from seeds of L. varius, and (+)-2P-hydroxyaphylline and (+)-13a-hydroxyaphyllidine from seeds ofZ,. hartwegii. Fig. (37) [225]. 

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