Acyclic Nucleoside Analogues: III. A Synthesis of New 2 ,3′-Dideoxy-2 ,3′-Didehydronucleoside Analogues

Abstract

The coupling of 5-acetoxy-1,1-dimethoxypent-2-ene with cytosine and thymine trimethylsilyl derivatives, as well as the reaction of 5-acetoxy-1-bromopent-2-ene with adenine sodium salt, yielded acyclic analogues of the corresponding nucleosides containing 5'-acetoxy groups. They were deprotected with a saturated methanolic solution of ammonia to the target analogues of nucleosides, which were characterized with 1H NMR, IR, and UV spectra. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.

Enantioselective 1,3‐Dipolar Cycloaddition Reactions of C‐Carboxy Ketonitrones and Enals with MacMillan Catalysts: Evidence of a Nonconcerted Mechanism

“…Fortunately, the functionalized enal (CH 2 OAc) 2E affords the exo product in a high ratio (92:8) in 82 % yield without the formation of isomer 5 (Table , Entry 4). Compound 2F with a CH 2 CH 2 OAc substituent gave an 86:14 exo/endo mixture in low yield (Table , Entry 5). The β‐aryl substituents in 2G and 2H resulted in slow reaction rates over 10 h without improved selectivities (Table , Entries 6 and 7).…”