Lactosyl urea

Lactosyl urea. Urea can serve as a cheap source of nitrogen for cattle but its use is limited because NH3 is released too quickly, leading to toxic levels of NH3 in the blood. Reaction of urea with lactose yields lactosyl urea (Figure 2.26), from which NH3 is released more slowly. 

In Switzerland, 92% of the whey is used for pig feed. Reaction with urea to form lactosyl urea permits greater quantities of non-protein nitrogen to be used in ruminant feeds. 

N-Lactosyl-urea and -thiourea derivatives have been obtained by condensation of lactosylamlne with long chain isocyanates and Iso-thlocyanates respectively. Muramoyl dipeptlde analogues (2) and (3) in which the sugar Is Joined to the peptide by a glycosylamine... 

Pinter s and Ichikawa s groups have used 73 (Scheme 18) for the synthesis of W-glycosyl ureas 74 in high yield in DMF [83] and in water [81, 84,85] in spite of the relative sensitivity of 73 to water. Following the same methodology, cellobiosyl and lactosyl azides 81 and 82 were transformed (Scheme 20) into the corresponding disaccharide oxazolidinones 83 and 84, which were used for the preparation of urea-tethered pseudooligosaccharides 85 and 86 [81]. 

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