Abstract. Candida antarctica lipase B (CAL-B

Abstract. Lipase from

A general procedure to obtain the 3'-aminoxylonucleosides 13a,b and 17a,b is presented. The synthetic scheme is based on the 5' directed intramolecular nucleophilic substitution at the 3'-activated position of the nucleoside. The approach of the incoming group to this position takes place regio- and stereoselectively from the most hindered face of the nucleoside. The methodology presented is applicable to ribonucleosides and 2'-deoxyribonucleosides, regardless of their nitrogenated base.

No abstract

A chemoenzymatic procedure is described for the synthesis of 3‘- and 5‘-carbazoyl nucleoside derivatives 12a,b, 13a,b, 14b,c, and 30b, and these are prepared for the first time. This process involves the regioselective enzymatic alkoxycarbonylation of nucleosides and the subsequent transformation with hydrazine into novel carbazoyl nucleoside derivatives. Taking into account previously reported data (relative to nucleoside, hydrazone, carbazate, and aryloxyphenoxypropionate derivatives), 3‘-alkylidencarbazoyl 2‘-deoxynucleosides 15a,b−18a,b, 5‘-alkylidencarbazoyl 2‘-deoxynucleosides 19a,b−22a,b, 5‘-alkylidencarbazoyl ribonucleosides of uridine 23c−26c, and 5‘-alkylidencarbazoyl-2‘,3‘-isopropylideneadenosine 31b−34b emerge as interesting targets since they combine structural features found in both therapeutic nucleoside derivatives and fungicide/herbicide nucleoside analogues.