title: Synthesis of novel 4'-carbon-substituted BCA derivatives based on radical cyclization.
abstract: Synthesis of (+/-)-4'-carbon-substituted BCA analogues (3) was carried out. Stereospecific construction of the cis-disposed 4'-carbon-substituent and 5'-hydroxy-methyl group was secured by employing the bicyclo-[3.3.0]lactone 11 as a key intermediate, which was prepared by radical-mediated 5-exo-trig cyclization of the phenylselenomethyl ester 10. After manipulation of the double bond of 11, 6-chloropurine was introduced based on the Mitsunobu reaction of the allyl alcohol 15. Ammonolysis of the resulting carbocyclic nucleoside led to the adenine derivative 16. Saponification of the bicylic lactone furnished the 4'-carboxylic acid 17 which serves as a precursor for other 4'-carbon-substituted analogues.
authors.affiliation: School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kumamoto
authors.forename: Nonoko
authors.initials: N
authors.lastname: Takahashi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Shimamura
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives*; D000998:Antiviral Agents / Q000138:chemical synthesis* / Q000737:chemistry; D003517:Cyclopentanes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000998:Antiviral Agents; D003517:Cyclopentanes; D000225:Adenine