摘要 : The alpha and beta anomers of 4'-thio-2'-deoxyuridine were readily synthesised as an anomeric mixture using adapted methodology and separated chromatographically as their 3',5'-di-O-benzyl-N-3-benzoyl derivatives. The 5-fluoro ana... 展开 The alpha and beta anomers of 4'-thio-2'-deoxyuridine were readily synthesised as an anomeric mixture using adapted methodology and separated chromatographically as their 3',5'-di-O-benzyl-N-3-benzoyl derivatives. The 5-fluoro analogs were prepared in a similar manner, but the anomers could be separated simply as their 3',5'-di-O-benzyl derivatives. The kinetics of acid-catalysed hydrolysis for the four compounds and their 5-alkylated analogs are reported. Under these conditions, cleavage of the N-glycosidic bond competes with the reversible isomerisation between the furano (4'-thio) and pyrano (5'-thio) ring systems. This was confirmed by isolation and NMR characterisation of the alpha and beta pyranose intermediates of the parent compounds. [References: 18] 收起