Activated carbohydrate lactones

Lundt I (2003) Iminosugars, isoiminosugars, and carbasugars from activated carbohydrate lactones efficient synthesis of biologically important compounds. In Witzak ZJ, Tatsuta K (eds) Carbohydrate synthons in natural products chemistry synthesis, functionalization and applications. ACS Symposium Series, vol 841. American Chemical Society, Washington, DC,pp 117-140... 

Iminosugars, Isoiminosugars, and Carbasugars from Activated Carbohydrate Lactones Efficient Synthesis of Biologically Important Compounds... 

Carboxymethyl glycoside lactones are easily prepared by diverse routes and react readily with nucleophilic species. Their reaction with amines, a simple addition which does not require any intermediate activation, is very general, and many examples of new pseudo-glycoconjugates prepared by this method are described. Moreover, 1,2-bisfunctionalized carbohydrate systems are efficiently constructed by reaction of the free OH on position 2 obtained after the opening of the lactone ring. Applications at the frontier of materials and biology have been envisaged and further studies in these fields will be reported in the near future. 

The regio- and stereo-selective functionalization of aldonolactones yields optically active lactones, which are important precursors in natural product synthesis. Concepts such as chiral templates and chirons, derived from carbohydrates, have been ingeniously and widely applied in synthesis (233). Among the commercially available aldonolactones, D-ribono-1,4-lactone is... 

The first of these was van t Hoff s principle of optical superposition, namely, that, in a compound having two or more asymmetric carbon atoms, the optical activities of the individual atoms can be added algebraically. This principle was applied with considerable success to carbohydrates by Hudson, in the form of his well known isorotation, lactone, and amide rules. These rules have been reviewed elsewhere, " and will not be discussed here. 

The biological activities depend on the structures of holothurian triterpene glycosides [42-44]. The structures of both an aglycon part and a carbohydrate chain are very important for the antifungal activity. The 18(20)-lactone presence is necessary for the activity, because the derivative 49 without the lactone does not show antifungal properties. 

Spirocyclic C-aryl glycosides and styryllactones are carbohydrate-based lactones. Spirocyclic C-aryl glycosides are isolated from a strain of Papularia sphaerosperna and constitute a family of novel antifungal antibiotics. They serve as an excellent antifungal agent against Candida tropicalis, Candida albicans and Pneumocystis carinii. Styryllactones are enantiomers of ([))-altholactone, a natural product which possesses antitumour and cytotoxic activities. 

Laszlo, E., Hollo, J., Hoschke, A. and Sarosi, G. (1978) The active center of amylolytic enzymes. I. A study by means of lactone inhibition of the role of "halfchair" glycosyl conformation at the active center of amylolytic enzymes, Carbohydr. Res., 61, 387-394. 

The ring contraction of carbohydrates constitutes a very useful route to functionalised and enantiomerically pure carbocycles. These compounds play a significant role in the construction of biologically active compounds such as enzyme regulators [24], the Corey lactone [25] and related prostaglandin intermediates [26], just to mention a few. 

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