indicine-n-oxide and Leukemia-P388

The C-9 and C-7 monoesters and C-7, C-9 diesters of heliotridine with (S)-(+) and (R)-(-)-2-hydroxy-2-phenylbutyric acid were prepared, converted into their N-oxides, and compared with the corresponding C-9 monoesters of retronecine in the in vivo P388 lymphocytic leukemia screen. Relative in vitro cytotoxicities of some of the free bases and their corresponding N-oxides were also measured against the A204 rhabdomyosarcoma cell line by using the soft agar colony forming assay. Stereochemistry at C-7 of the necine and at C-2' of the necine acid appears to have a significant effect on the antitumor activity in this system. In the heliotridine series, the configuration of the necic acid has a pronounced effect on the site selectivity (C-7 vs C-9) in esterification with carbodiimidazole. An explanation for this site selectivity is offered.

Topics: Animals; Antineoplastic Agents; Chemical Phenomena; Chemistry; Esters; Humans; Leukemia P388; Pyrrolizidine Alkaloids; Structure-Activity Relationship; Tumor Cells, Cultured

The 2,3-bis[[(N-methylcarbamoyl)oxy]methyl]-3-pyrroline 1-oxide 5 was synthesized and tested in the murine P388 lymphocytic leukemia model. The compound showed significant reproducible activity and was more potent than indicine N-oxide. 1-Methyl-2-phenyl-3,4-bis[[(N-2- propylcarbamoyl)oxy]methyl]-3-pyrroline N-oxide (6) was less active than 5, and the 5,5-dimethyl analogue of 6, the pyrroline N-oxide 7, was inactive. The N-oxide 7 cannot be converted to a pyrrole in vivo because of the gem-dimethyl substitution at C-5.

Topics: Animals; Antineoplastic Agents; Leukemia P388; Mice; Pyrroles; Pyrrolizidine Alkaloids; Structure-Activity Relationship

(-)- and (+)-trachelanthic and (-)- and (+)-viridifloric acids were synthesized and their isopropylidene derivatives were regiospecifically coupled, at C-9, with (-)-retronecine obtained by hydrolysis of monocrotaline, isolated from Crotalaria spectabilis. Hydrolysis, followed by oxidation, led to the N-oxides of indicine, intermedine, lycopsamine, and the new nonnatural product, respectively. Each of these analogues was screened in the P388 lymphocytic leukemia system at the same time as indicine N-oxide, and the results were compared. Other related analogues were prepared and similarly screened and the results compared with those from indicine N-oxide.

Topics: Animals; Antineoplastic Agents; Leukemia P388; Magnetic Resonance Spectroscopy; Mice; Pyrrolizidine Alkaloids