title: Chemo-, regio-, and stereoselectivity of F-ring opening reactions in the cephalostatin series.
abstract: In an effort to prepare unsymmetrical cephalostatin analogues with multi-functionality, we tried the route of selective opening of the spiroketal joining rings E and F. In this study, we have tested several borane complexes (like borane-9-BBN, borane-(N-tosyl)-D-valine, and borane-catechol) with some bis-steroidal pyrazine derivatives like 3, 4, and 16 aiming at opening ring-F at only one spiro-system of the dimer. Upon testing these borane reagents, satisfying results were obtained in the case of the keto-methylene 4 using the catechol-borane complex. The structures of the resulting mono-opened and also some double-opened spiro dimers have been completely confirmed. Some of the prepared compounds were tested against three cancer cell lines: HM02 (stomach cancer), HEP G2 (hepatocellular cancer), and MCF 7 (breast cancer).
authors.affiliation: Basic Sciences Department, Faculty of Engineering Technology, Al-Balqa Applied University, PO Box 15008, 11134 Amman, Jordan. MNawasra@fet.edu.jo
authors.forename: M
authors.initials: M
authors.lastname: Nawasreh
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D001880:Boranes / Q000737:chemistry; D001943:Breast Neoplasms; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008113:Liver Neoplasms; D010619:Phenazines / Q000737:chemistry* / Q000494:pharmacology; D011719:Pyrazines / Q000737:chemistry; D013141:Spiro Compounds / Q000737:chemistry* / Q000494:pharmacology; D013256:Steroids / Q000737:chemistry* / Q000494:pharmacology; D013274:Stomach Neoplasms; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; D001880:Boranes; D010619:Phenazines; D011719:Pyrazines; D013141:Spiro Compounds; D013256:Steroids; C454806:cephalostatin I