2348-00-7Relevant articles and documents
Triterpene and steroidal glycosides of the genus Melilotus and their genins. VI. Melilotoside A2 and adzukisaponin v from the roots of M. tauricus
Khodakov
, p. 1024 - 1026 (2013)
Two triterpene glycosides of the oleanane series, melilotoside A 2 and previously known adzukisaponin V, were isolated from the roots of Melilotus tauricus (L.) Pall. (Fabaceae). The structures of the glycosides were proved based on chemical transformations. Melilotoside A2 had the structure soyasapogenol B 3-O-β-D-glucouronopyranoside; adzukisaponin V, soyasapogenol B 3-O-[α-L-rhamnopyranosyl-(1-2)-β-Dglucopyranosyl- (1-2)-β-D-glucuronopyranoside].
Tandem epoxidation-alcoholysis or epoxidation-hydrolysis of glycals catalyzed by titanium(IV) isopropoxide or Venturello's phosphotungstate complex
Levecque, Pieter,Gammon, David W.,Kinfe, Henok Hadgu,Jacobs, Pierre,De Vos, Dirk,Sels, Bert
body text, p. 1557 - 1568 (2009/07/10)
Venturello's phosphotungstate complex and titanium(IV) isopropoxide [Ti(O-i-Pr)4] were successfully used as catalysts for the epoxidation-alcoholysis of glycals using hydrogen peroxide [H2O 2]. Reaction substrates included a range of variously protected glycals and different alcohols were used as solvents. Ti(O-i-Pr)4 was only effective in methanol as solvent, but gave methyl glycosides in high yields and high selectivities. The Venturello complex proved to be a very versatile and efficient catalyst. Apart from epoxidation-alcoholysis in alcoholic solvents it also showed activity in biphasic conditions to allow for glycosylation of long-chain alcohols and was very effective in the stereoselective dihydroxylation of benzylated glucal.
Naphthyl 3,4,6-tri-O-methyl-β-D-glucopyranoside as a chiral auxiliary in an asymmetric 1,4-addition reaction
Chiappe, Cinzia,Lo Moro, Giacomo,Munforte, Paola
, p. 2311 - 2317 (2007/10/03)
Naphthyl 3,4,6-tri-O-methyl-β-D-glucopyranoside, easily synthesized from tri-O-acetyl-D-glucal, has been applied as a chiral auxiliary in an asymmetric Michael addition to the 2-O-crotonate. A very high facial diastereoselection (>95%) was obtained. No diastereoselection was observed when 1,3,4,6-tetra-O-methyl-β-D-glucopyranoside was used as the chiral auxiliary. A stereochemical model, taking into account steric shielding and π-stacking effects, is proposed on the basis of the observed results.