title: A concise effective deprotection of spiro 3-cyclic thiaza ketal of steroidal 1,4-dien-3-one.
abstract: An effective deprotective method of spiro 3-cyclic thiaza ketal of steroidal 1,4-dien-3-ones using alkyl vinyl ether in the presence of protic acid followed by the treatment of aqueous alkali was described. This novel protocol could be fulfilled under mild condition with high yield. The mechanism mediated by a carbonium ion formed in situ was clarified by the capture of the cleaved fragment.
authors.affiliation: Department of Medicinal Chemistry, Pharmacy School, Fudan University, Yi Xue Yuan Road 138, Shanghai 200032, China.
authors.forename: Bei Na
authors.initials: BN
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Xia
mesh_terms: D002384:Catalysis; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004355:Drug Stability; D007202:Indicators and Reagents / Q000737:chemistry*; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013256:Steroids / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D007202:Indicators and Reagents; D013141:Spiro Compounds; D013256:Steroids