Chemical transformation of protoberberines. XV. A novel and efficient method for the introduction of alkyl groups on the C-13 position in the protoberberine skeleton.
A novel and efficient synthesis of 13-methylprotoberberine alkaloids
作者:Miyoji Hanaoka、Shuji Yoshida、Chisato Mukai
DOI:10.1039/c39850001257
日期:——
13-Methylberberine (6a), dehydrocorydaline (6b), and corysamine (6c, and their tetrahydro derivatives (9a–c) were efficiently synthesised from the corresponding protoberberines (1) through photochemical electrocyclic reaction of 13-methylene-8, 14-cycloberbines (3).
Chemical transformation of protoberberines. XV. A novel and efficient method for the introduction of alkyl groups on the C-13 position in the protoberberine skeleton.
作者:Miyoji HANAOKA、Shuji YOSHIDA、Chisato MUKAI
DOI:10.1248/cpb.37.3264
日期:——
The Wittig reaction of 8, 14-cycloberbin-13-ones (4), derived from the corresponding protoberberine alkaloids (2), with methylenetriphenylphosphorane afforded 13-methylene-8, 14-cycloberbines (5). Irradiation of 5 with a 100 W high pressure mercury lamp effected photochemically-induced electrocyclic fission of the aziridine ring to yield 13-methylberberine (1a), dehydrocorydaline (1b), and corysamine (1c) in high yield. Introduction of ethyl and propyl groups on the C-13 position in 2 was also conveniently achieved via photochemical reaction of the corresponding alkylidene derivatives (8 and 9, respectively).