| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a new neuraminic acid compound having high sialidase- inhibitory activity in vivo, and useful for treating/preventing viral infections diseases, esp. influenza. SOLUTION: This new compound is shown by formula I [R<1> is a (halogen- substituted) methyl; R<2> , R<3> and R<4> are each H or a 3-25C aliphatic acyl; W is H or an ester residue; excepting that R<1> is methyl and R<2> , R<3> , R<4> and W are each H], e.g. 5-acetamido-2,3,4,5-tetradeoxy-4-guanidino-9-o-hexanoyl-D- glycero-D-galact-one-2-enopyranosonic acid. The compound of formula I is obtained by reaction of a compound of formula II (R<2a> is the same as R<2> or is an OH-protecting group; R<3a> is the same as R<3> or is an OH-protecting group; R<4a> is the same as R<4> or is a protected OH; W<a> is the same as W or is a carboxyl-protecting group) with N,N'-di-t-butoxycarbonyl thiourea to form a compound of formula III (Boc is t-butoxycarbonyl), which is then reacted with a reagent for eliminating the t-butoxycarbonyl group.</p> |
