129834-75-9Relevant academic research and scientific papers
Synthesis of novel analogues of the calicheamicin γ1 and esperamicin A1B oligosaccharides
Moutel, Stephane,Prandi, Jacques
, p. 305 - 315 (2007/10/03)
The chemical synthesis of three analogues of the calicheamicin γ1 and esperamicin A1B 2 oligosaccharides is described in which the carbohydrate ring E is replaced by a basic side chain E'. Our synthetic strategy begins with ABE' fragment construction which possesses an unusual β N-O glycosidic bond. Glycosylation of the nitrone 20 and the appropriate activated sugar B 13 or 22 gives the disaccharides 23 and 24 respectively. Esperamicin A1B oligosaccharide analogue 5 is obtained after two deprotection steps of the fragment 24. After removal of the protecting groups of unit 23, the fully deprotected disulfide 33 is reduced and immediately coupled with the deprotected aromatic unit C 30 (or CD 31) to provide the calicheamicin γ1 oligosaccharide analogues 3 and 4. We also report the synthesis of hemiacetal 7 in which the thioester function between the CD and B rings is replaced by an ester linkage. This arylsaccharide is a key intermediate required for the synthesis of a novel calicheamicin γ1 analogue 6.
Synthesis of a novel analogue of the BCD carbohydrate domain of calicheamicin γ1
Moutel, Stephane,Prandi, Jacques
, p. 9667 - 9670 (2007/10/03)
The efficient preparation of a novel analogue of the BCD oligosaccharide domain of Calicheamicin γ1 is described in which the thioester linkage found in the natural product is replaced by an ester group.
Studies related to the carbohydrate sectors of esperamicin and calicheamicin: Definition of the stability limits of the esperamicin domain and fashioning of a glycosyl donor from the calicheamicin domain
Halcomb, Randall L.,Boyer, Serge H.,Wittman, Mark D.,Olson, Steven H.,Denhart, Derek J.,Liu, Kevin K. C.,Danishefsky, Samuel J.
, p. 5720 - 5749 (2007/10/02)
The core trisaccharide regions of esperamicin and the aryltetrasaccharide region of calicheamicin have been synthesized. The minimum protection modalities necessary to stabilize structures against rearrangement to an isomeric azafuranose series were ascertained (see compounds 12 and 65). Deprotection of the 2-(trimethylsilyl)-ethoxycarbonyl carbamate from 65 led to azafuranose 14 characterized as methyl glycoside 15. Using this insight, it was possible to fashion, for the first time, a pre-glycosyl donor (see compound 128) corresponding to the complete arylsaccharide sector of calicheamicin γ1I at the oxidation level of the domain. Among the key assembly strategies were the conversion of α-thiophenylpseudoglycals to allal derivatives (see 44 → 45); the interfacing of epoxide-mediated glycosylation with iodoglycosylation (see 30 → 47 → 48); the synthesis of hydroxylamine glycosides via inflate displacement (see 61 + 91 → 101); and a new route to p-hydroxybenzonitriles (see formation of 86).
Total synthesis of calicheamicin γ1I. 1. Synthesis of the oligosaccharide fragment
Groneberg,Miyazaki,Stylianides,Schulze,Stahl,Schreiner,Suzuki,Iwabuchi,Smith,Nicolaou
, p. 7593 - 7611 (2007/10/02)
The first total synthesis of the calicheamicin γ1I oligosaccharide fragment in the form of its methyl glycoside (62) has been achieved. The synthetic challenge of the B-ring was recognized and studied initially, resulting in a novel and unique solution to the stereochemical problems posed involving a [3,3]-sigmatropic rearrangement of an allylic thionoimidazolide (111). This chemistry was initially worked out on a model for the ABC-ring system (47) and then successfully applied to the real system. The success of this synthesis has enabled the completion of the first synthesis of the natural product itself, calicheamicin γ1I (1), as will be described in the following papers in this issue.
