- Efficient synthesis of α-branched purine-based acyclic nucleosides: Scopes and limitations of the method
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An efficient route to acylated acyclic nucleosides containing a branched hemiaminal ether moiety is reported via three-component alkylation of N-heterocycle (purine nucleobase) with acetal (cyclic or acyclic, variously branched) and anhydride (preferentially acetic anhydride). The procedure employs cheap and easily available acetals, acetic anhydride, and trimethylsilyl trifluoromethanesulfonate (TMSOTf). The multi-component reaction is carried out in acetonitrile at room temperature for 15 min and provides moderate to high yields (up to 88%) of diverse acyclonucleosides branched at the aliphatic side chain. The procedure exhibits a broad substrate scope of N-heterocycles and acetals, and, in the case of purine derivatives, also excellent regioselectivity, giving almost exclusively N-9 isomers.
- Dra?ínsky, Martin,Frydrych, Jan,Janeba, Zlatko,Slavětínská, Lenka Po?tová
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- Process for preparing purine derivates
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There is disclosed a process for preparing purine derivatives of the formula I wherein, R1 represents hydrogen, CH3CO or a higher acyl,R3 represents hydrogen, CH3CO or a higher acyl, CF3CO, CCl3CO, PhCO or CH2 AR, such as benzyl or substituted benzyl, and benzoisothiazolyl-S,S-dioxide, and, Z represents OH, hydrogen or halo. Said compounds are either drugs or prodrugs for the treatment of herpes infections. There are also disclosed some novel compounds of formula I useful as prodrugs.
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