148926-02-7Relevant articles and documents
Synthetic Investigation toward QS-21 Analogues
Hu, Zhen-Ni,Liao, Jin-Xi,Liu, De-Yong,Sun, Jian-Song,Zeng, Zhi-Yong,Zhang, Qing-Ju
, (2020)
With glycosyl o-alkynylbenzotes as donors, a highly efficient protocol to construct the challenging glycosidic linkages at C3-OH of C23-oxo oleanane triterpenoids is disclosed, on the basis of which different strategies for the highly efficient synthesis of QS-21 analogues with the west-wing trisaccharide of QS-21 have been established.
Isoquinoline-1-Carboxylate as a Traceless Leaving Group for Chelation-Assisted Glycosylation under Mild and Neutral Reaction Conditions
Wang, Hao-Yuan,Simmons, Christopher J.,Blaszczyk, Stephanie A.,Balzer, Paul G.,Luo, Renshi,Duan, Xiyan,Tang, Weiping
supporting information, p. 15698 - 15702 (2017/11/13)
Glycosyl isoquinoline-1-carboxylate was developed as a novel benchtop stable and readily available glycosyl donor. The glycosylation reaction was promoted by the inexpensive Cu(OTf)2 salt under mild reaction conditions. The copper isoquinoline-1-carboxylate salt was precipitated from the solution and thus rendered a traceless leaving group. Surprisingly, the proton from the acceptor was absorbed by the precipitated metal complex and the reaction mixture remained at neutral pH. The copper-promoted glycosylation was also proven to be completely orthogonal to the gold-promoted glycosylation, and an iterative synthesis of oligosaccharides from benchtop stable anomeric ester building blocks becomes possible under mild reaction conditions.
Synthetic studies of complex immunostimulants from Quillaja saponaria: Synthesis of the potent clinical immunoadjuvant QS-21Aapi
Kim, Yong-Jae,Wang, Pengfei,Navarro-Villalobos, Mauricio,Ronde, Bridget D.,Derryberry, JohnMark,Gin, David Y.
, p. 11906 - 11915 (2007/10/03)
QS-21 is one of the most promising new adjuvants for immune response potentiation and dose-sparing in vaccine therapy given its exceedingly high level of potency and its favorable toxicity profile. Melanoma, breast cancer, small cell lung cancer, prostate cancer, HIV-1, and malaria are among the numerous maladies targeted in more than 80 recent and ongoing vaccine therapy clinical trials involving QS-21 as a critical adjuvant component for immune response augmentation. QS-21 is a natural product immunostimulatory adjuvant, eliciting both T-cell- and antibody-mediated immune responses with microgram doses. Herein is reported the synthesis of QS-21 Aapi in a highly modular strategy, applying novel glycosylation methodologies to a convergent construction of the potent saponin immunostimulant. The chemical synthesis of QS-21 offers unique opportunities to probe its mode of biological action through the preparation of otherwise unattainable nonnatural saponin analogues.
Is acyl migration to the aglycon avoidable in 2-acyl assisted glycosylation reactions?
Berces, Attila,Whitfield, Dennis M.,Nukada, Tomoo,Do Santos Z, Iwona,Obuchowska, Agnes,Krepinsky, Jiri J.
, p. 1157 - 1171 (2007/10/03)
This report unequivocally separates orthoester formation from acyl transfer for the first time and indicates possible routes to eliminate 2-O-acyl transfer during glycosylation reactions. Experimental evidence is shown that acyl transfer from 2-O-acyl-3,4
Synthesis of the trisaccharide portion of soyasaponin βg: Evaluation of a new glucuronic acid acceptor
Ple, Karen
, p. 1441 - 1454 (2007/10/03)
The synthesis of the trisaccharide portion of soyasaponin βg was successfully achieved using a new glucuronic acid acceptor: methyl 1-O-allyl-3,4-di-O-methoxymethyl-β-D-glucuronate (9). This compound and methyl 1-O-allyl-3,4-di-O-tert-butyldimethylsilyl-β
Comparing n-pentenyl orthoesters and n-pentenyl glycosides as alternative glycosyl donors
Mach, Mateusz,Schlueter, Urs,Mathew, Felix,Fraser-Reid, Bert,Hazen, Kevin C
, p. 7345 - 7354 (2007/10/03)
As is well known, cyclic 1,2-glycosyl orthoesters undergo ready acid catalyzed rearrangement to 2-O-acyl glycosides in which the alkoxy group is transferred from the orthoester to the anomeric center in a highly stereocontrolled process. The related n-pentenyl derivatives are unique in that either the orthoester (NPOE) or its rearrangement product (NPGAC) can function as a glycosyl donor, and mechanistic considerations indicate that both should (or could!) lead to the same product(s) arising from trans-orthoesterification, glycosidation, glycosyl esterification, etc. Experiments are described which show that the product obtained from a given reaction can be optimized by careful choice of the donor, NPOE or related NPGAC, and careful attention to reaction conditions, electrophilic promoter, 'size' of the glycosyl acceptor, and experimental protocol.
Total synthesis of vancomycin - Part 4: Attachment of the sugar moieties and completion of the synthesis
Nicolaou,Mitchell, Helen J.,Jain, Nareshkumar F.,Bando, Toshikazu,Hughes, Robert,Winssinger, Nicolas,Natarajan, Swaminathan,Koumbis, Alexandros E.
, p. 2648 - 2667 (2007/10/03)
The total synthesis of vancomycin (1, Figure 1) is described. The successful plan for this synthesis involves sequential and stereoselective coupling of vancomycin aglycon acceptor 6 and glycosyl donors, trichloroacetimidate 50 and glycosyl fluoride 27 (Scheme 8). Acceptor 6 was synthesized from vancomycin aglycon (2) (Scheme 1), which was derived both by total synthesis and by semisynthesis from vancomycin itself (1) (Scheme 2). The vancosamine derivative 27 was obtained by total synthesis (Scheme 3) while the glycosyl derivative 50 was prepared from glucal (46) (Scheme 6). A number of glycosidation model studies, carried out in order to establish the final route to vancomycin (1), are also described and so are a number of failed attempts to secure the target molecule (1).
