title: A novel, mild, and facile method to prepare 6-methylidene penem derivatives.
abstract: A novel and mild method was established to synthesize 6-methylidene penem compounds. This method entails a MgBr(2)/Et(3)N-promoted aldol-type condensation on 6-bromopenem 12 with an appropriately substituted aldehyde to yield the intermediate acetylated bromohydrin, which was smoothly converted to the final product with simultaneous deprotection of C3 carboxylic acid ester using activated zinc dust and phosphate buffer at pH 6.5. This process provides a useful variation of C-C bond formation method for penem derivatives and also serves as a practical synthetic method to prepare 6-exomethylenepenem derivatives without racemization at the C5 position.
authors.affiliation: Medical Research Laboratories, Wyeth Lederle Japan, Ltd., 1-6-34 Kashiwa-cho, Shiki-shi, Saitama 353-8511, Japan. takao_abe@meiji.co.jp
authors.forename: Takao
authors.initials: T
authors.lastname: Abe
authors.forename: Chisato
authors.initials: C
authors.lastname: Sato
authors.forename: Hideki
authors.initials: H
authors.lastname: Ushirogochi
authors.forename: Koichi
authors.initials: K
authors.lastname: Sato
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takasaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Isoda
authors.forename: Ado
authors.initials: A
authors.lastname: Mihira
authors.forename: Itsuki
authors.initials: I
authors.lastname: Yamamura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hayashi
authors.forename: Toshio
authors.initials: T
authors.lastname: Kumagai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tamai
authors.forename: Motoo
authors.initials: M
authors.lastname: Shiro
authors.forename: Aranapakam M
authors.initials: AM
authors.lastname: Venkatesan
authors.forename: Tarek S
authors.initials: TS
authors.lastname: Mansour
mesh_terms: D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D007769:Lactams / Q000138:chemical synthesis*; D015394:Molecular Structure; D013329:Structure-Activity Relationship
chemical_list: D007769:Lactams