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)
01), formic aceticanhydride (0.02 ± 0.01) and peroxyacetyl nitrate (PAN); from n-propyl acetate, acetoxyacetaldehyde (0.22 ± 0.06), formic aceticanhydride (0.28 ± 0.03), acetic acid (0.15 ± 0.02), acetaldehyde (0.35 ± 0.10), peroxypropionyl nitrate (PPN) and probably acetoxypropionaldehyde (0.30 ± 0.10). From these data, oxidation schemes of these two acetates were elucidated. This study reveals
Preparation of intermediates useful in the synthesis of antiviral nucleosides
申请人:——
公开号:US20030162992A1
公开(公告)日:2003-08-28
The present invention is an efficient process for the manufacture of &agr;-acyloxyacetaldehyde, a key intermediate in the synthesis of 1,3-oxathiolane and 1,3-dioxolane nucleosides.
Silver halide photographic light-sensitive material
申请人:KONICA CORPORATION
公开号:EP0110633A2
公开(公告)日:1984-06-13
A silver halide photographic light-sensitive material is described which comprises a support having thereon a plurality of silver halide emulsion layers which possess different speeds but sensitivities in the same spectral region and at least one light-sensitive layer comprising a non-diffusible coupler capable of forming non-diffusible dye by reaction with an oxidation product of a color developing agent, wherein the silver halide emulsion layer having the highest speed among said plurality of silver halide emulsion layers contains a non-diffusible coupler capable of producing a movable dye by reaction thereof with an oxidation product of a color developing agent and a non-diffusible compound capable of releasing a development inhibitor by reaction thereof with an oxidation product of a color developing agent.