title: Chemical modification of antitumor alkaloids, 20(S)-camptothecin and 7-ethylcamptothecin: reaction of the E-lactone ring portion with hydrazine hydrate.
abstract: The structure of the N-amino pyridone (4a) obtained by the reaction of camptothecin (1a) with hydrazine was determined by X-ray crystallography. A mixture of 7-ethylcamptothecin (1b) and hydrazine hydrate was stirred at room temperature, and the hydrazide (2b) was isolated as its diacetate 2c. Treatment of the 17-O-acetyl amide (5a) with hydrazine gave 1b (74% yield) and the N-amino lactam 6 (11% yield). Compounds with bulky acyl groups, 5c--e, gave 6 in modest yields. The N-amino lactam 6 was smoothly dehydrated into the pyridone 4d by refluxing in hydrazine hydrate.
authors.affiliation: Yakult Central Institute for Microbiological Research, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yaegashi
authors.forename: S
authors.initials: S
authors.lastname: Sawada
authors.forename: T
authors.initials: T
authors.lastname: Furuta
authors.forename: T
authors.initials: T
authors.lastname: Yokokura
authors.forename: K
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: T
authors.initials: T
authors.lastname: Miyasaka
mesh_terms: D000818:Animals; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D005260:Female; D006834:Hydrazines / Q000737:chemistry; D007939:Leukemia L1210 / Q000188:drug therapy; D051379:Mice
chemical_list: D006834:Hydrazines; C029424:hydrazine; D002166:Camptothecin