294203-76-2

Upstream product

• 104495-20-7 2,3,4-tris-O-(phenylmethyl)-α-L-rhamnopyranosyl fluoride 
• 20728-73-8 5,7,3',4'-tetra-O-benzyl-(+)-catechin 
• 80152-99-4 1-O-acetyl-2,3,4-tri-O-benzyl-6-deoxy-α-L-mannose 

Downstream Products

• 294203-79-5 (2R,3R)-5,7-Bis-benzyloxy-2-(3,4-bis-benzyloxy-phenyl)-3-((2S,3R,4R,5S,6S)-3,4,5-tris-benzyloxy-6-methyl-tetrahydro-pyran-2-yloxy)-chroman-4-one 
• 29838-67-3 astilbin 
• 294203-78-4 (2R,3S,4S)-5,7-Bis-benzyloxy-2-(3,4-bis-benzyloxy-phenyl)-3-((2S,3R,4R,5S,6S)-3,4,5-tris-benzyloxy-6-methyl-tetrahydro-pyran-2-yloxy)-chroman-4-ol 

Relevant academic research and scientific papers

Cationic zirconocene- or hafnocene-based Lewis acids in organic synthesis: Glycoside-flavonoid analogy

Cationic metallocene species, generated from Cp2MCl2 and AgClO4 (M=Zr, Hf), were used for the glycosylation of catechin derivative 2, enabling a concise synthesis of a glycosyl flavonoid, astilbin (1). Further study revealed the efficiency of this Lewis acidic species for SN1-type activation of the C(4) position of catechin derivative 11, enabling selective substitution with various nucleophiles.

PROCESS FOR PREPARING FLAVONOIDS

A simple and easy process for preparing pharmacologically useful flavonoid compound having reductase inhibitory effect, active oxygen extinguishing effect, carcinogenesis promotion inhibitory effect, anti-inflammatory effect, and so on. Particularly, a process for preparing the compound of the formula (I): ???wherein, R2 is a substituted or un-substituted phenyl group; ???R7 is a hydrogen atom or a hydroxyl group; and n is an integer of 1 to 4; by bonding a sugar derivative to catechins as the starting compound selectively via O-glycoside bond and then oxidizing the 4-position of flavanoid skeleton of the obtained compound.

First synthesis of astilbin, biologically active glycosyl flavonoid isolated from Chinese folk medicine

A synthetic route to a biologically active glycosyl flavonoid, astilbin (1), was developed. The tetra-benzyl ether 4, derived from (+)-catechin, was glycosylated with the L-rhamnosyl donor 10 by using Cp2HfCl2-AgClO4, and subsequent oxidation of the C(4)position of the flavan skeleton followed by deprotection gave 1. (C) 2000 Elsevier Science Ltd.