Senecio- alkaloids

Sencor — see l,2,4-Triazin-5-one, 4-amino-6-t-butyl-3-methylthio-Senecio alkaloids structure, 7, 658 Senepoxide, 7, 192 Senkirkine conformation, 7, 703 structure, 7, 658 Sensitizing dyes... 

Senecio alkaloids, see Pyirolizidine alkaloids Secoisoquinoline alkaloids, 33, 231 (1988) Securinega alkaloids, 14, 425 (1973) Sinomenine, 2, 219 (1952)... 

Senecio alkaloids, see Pyrrolizidine alkaloids Sesquiterpene pyridine alkaloids, 60, 287 (2003)... 

McLean, E. K. 1970. The toxic actions of pyrrolizidine (Senecio) alkaloids. Pharmacological Review, 22 429 83. 

Some Senecio alkaloids have opened pyrrolizidine ring systems which show transannular interactions and are closely related in structure to the compounds discussed above. The alkaloid senkirkine is a cyclic ester of (37) (74JA6165) and its X-ray structure shows a rather short transannular contact of 2.23 A. 

Aromatic azapentalenes have not been found naturally, though an imidazo[4,5-d]imidazole derivative has been implicated in the prebiotic synthesis of purines130 74 (see also Section III,A,l,d). Saturated derivatives occur fairly widely the Senecio alkaloids contain the reduced pyrrolol l,2-a]pyrrole (pyrrolizidine) skeleton,487 and the alkaloid withasomnine is a derivative of pyrrolo[ l,2-6]pyrazole.374,488 The mitomycin antibiotics mentioned earlier in this review (Sections III,B,l,f and III,B,5) contain the pyrrolol l,2-a]indole ring,166,331 and the recently reported fungal metabolite sporidesmin is a saturated derivative of pyrrolo[2,3-6]indole.489... 

Mattocks A. R. (1972) Toxicity and metabolism of Senecio alkaloids. In Phytochemical Ecology, ed. J. B. Harborne pp. 179-200. Academic Press, New York. 

F. L. Warren, Fortschr. Chem. Org. Naturstoffe 12, 198-269 (1955). Senecio alkaloids ... 

Schoental, R. and Magee, P. N. (1959). Further observations on the subacute and chronic liver changes in rats after a single dose of various pyrrolizidine (Senecio) alkaloids. J. Path. Bact. 78, 471-482. 

In agreement with frontier orbital considerations, crotonic esters add to nitrones to produce p-o o esters regioselectively. This reaction provides the basis for a synthesis of the Senecio alkaloid supinidine (7). Reaction of 1 with methyl 4-hydroxycrotonate yields the isoxazolidinone 5, which is easily converted to the... 

Fig. 29.10 Intima proliferation and thrombosis of a (radicular) hepatic vein resulting from Senecio alkaloids (HE) (s. tab. 29.10)...

Schoental R, Head MA, and Peacock PR (1954) Senecio alkaloids Primary liver tumours in rats as a result of treatment with (1) mixture of alkaloids from S. Jacobaea Lin, (2) Retrorsine, (3) Isatidine. British Journal of Cancer 8 458 65. 

In synthetic work in the Senecio alkaloid series, Adams and co-workers ° prepared a 1-hydroxypyrrolizidine of the desired stereochemistry (2) by Rh-AljOj hydrogenation of (1), a reaction involving complete saturation of the dienone system. 

Retrorsi ne.seneci oni ne, seneciphylline Preparative LC of senecio alkaloids 500/C18 column 2 columns Me0H-0.005M KH2P04(pH 6.3)(3 2) 17... 

---