Abstract
In order to explore a new cleavage method for an arabinoside or a galactoside linkage which attaches to a triterpenoidal or a steroidal aglycone, a photochemical method has been investigated. It has been found that glycoside linkages in 2'-keto-arabinoside and 2'-keto-galactoside derivatives of triterpenoids and a steroid are cleaved upon photolysis to furnish their aglycones in their oxidized forms. In addition, it has been shown that, through the present photochemical procedure, an arabinoside linkage in ziyu-glycoside II (8), which has been known to give an artifact aglycone upon ordinary acid hydrolysis, is cleaved while its acid-labile moiety in the aglycone part is left unchanged.
