23262-64-8Relevant articles and documents
Selective cleavage of methoxy protecting groups in carbohydrates
Boto, Alicia,Hernandez, Dacil,Hernandez, Rosendo,Suarez, Ernesto
, p. 1938 - 1948 (2007/10/03)
The selective cleavage of methoxy protecting groups next to hydroxy groups is achieved using a radical hydrogen abstraction reaction as the key step. Under the reaction conditions, the hydroxy group generates an alkoxyl radical that reacts with the sterically accessible adjacent methoxy group, which is transformed into an acetal. In the second step, the acetals are hydrolyzed to give alcohols or diols. A one-pot hydrogen abstraction-hydrolysis procedure was also developed. Good yields were usually achieved, and the mild conditions of this methodology were compatible with different functional groups and sensitive substrates such as carbohydrates.
Five Steroidal Components from the Rhizomes of Polygonatum odoratum var. pluriflorum
Sugiyama, Mari,Nakano, Kimiko,Tomimatsu, Toshiaki,Nohara, Toshihiro
, p. 1365 - 1372 (2007/10/02)
Five steroidal components (PO-a(1)-PO-e(5)) were obtained from the methanolic extract or its partial hydrolysate of the fresh rhizomes of Polygonatum odoratum var.Pluriflorum, and their chemical structures were characterized as (25 R and S)-spirost-5-en-3β,14α-diol, 3-O-β-D-glucopyranosyl-(1->2)-3)>-β-D-glucopyranosyl-(1->4)-β-D-galactopyranosyl(=β-lycotetraosyl)-(25 R and S)-spirost-5-en-3β,14α-diol, 3-O-β-lycotetraosyl-22-methoxy-(25 R and S)-furost-5-en-3β,14α,26-triol 26-O-β-D-glucopyranoside, 3-O-β-D-glucopyranosyl-(1->2)-3)>-β-D-glucopyranosyl(1->4)-β-D-galactopyranosyl-22-methoxy-(25 R and S)-furost-5-en-3β,14α,26-triol 26-O-β-D-glucopyranoside and 3-O-β-lycotetraosyl yamogenin, respectively.Moreover, (25 S)-spirost-5-en-3β,14α-diol (7) was isolated from a mixture of the (25 R) and (S) derivatives of PO-a (1) and it was designated as neoprazerigenin A.Keywords - Polygonatum odoratum var. pluriflorum; Liliaceae; neoprazerigenin A; spirostanol glycoside; furostanol glycoside.