Amines glycosides

The mechanism of isomerization of amine glycosides has been discussed by Howard, Kenner, Lythgoe and Todd,107 while the literature regarding N-glycosides in general has been briefly reviewed by Honeyman and Tatchell.143... 

The reaction conditions applied are usually heating the amine with a slight excess of aldehyde and a considerable.excess of 2d-30hydrochloric acid at 100 °C for a few hours, but much milder ( physiological ) conditions can be used with good success. Diols, olefinic double bonds, enol ethers, and glycosidic bonds survive a Pictet-Spengler reaction very well, since phenol and indole systems are much more reactive than any of these acid sensitive functional groups (W.M. Whaley, 1951 J.E.D. Barton, 1965 A.R. Battersby, 1969). 

For conversion of amide to other acid derivatives, a novel synthesis of urea glycosides in aqueous media has been reported via the reaction of Steyermark s glucosyl carbamate with amines in good yields (Eq. 9.17).38 This method was successfully applied to develop a new route to the synthesis of urea-tethered neo-glycoconjugates and pseudooligosaccharides. 

Hemiacetal hydroxyl groups of carbohydrate molecules also may be coupled to amine-containing molecules to form N-glycosidic linkages, such as those in nucleic acids and oligonucleotides. 

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. 

---