Letters in Organic Chemistry - Volume 1, Issue 2, 2004

An improved method for the synthesis of trimethylsilylethyl chloroformate (Teoc-Cl) was studied in great detail. N-Teoc-adenosine, N-Teoccytidine and their deoxyribonucleoside derivatives were synthesized as the key synthetic intermediates for the synthesis of base-sensitive oligonucleotide derivatives by use of N-methylimidazole. The stability and chemical properties of these Nprotected nucleoside derivatives were examined.

The applicability of 2,2-bis(ethoxycarbonyl)-3-(pivaloyloxy)propyl and 2- cyano-2-(2-phenylethylaminocarbonyl)-3-(pivaloyloxy)propyl groups as biodegradable protecting agents for the internucleosidic linkages of phosphorothioate antisense oligonucleotides has been studied. For this purpose, protected phosphoromonothioates of thymidylyl-(3'→5')-thymidine [Tp(s)T] containing either a bridged or non-bridged sulfur atom have been prepared, and their chemical stability and enzymatic deprotection have been studied.

Four unprecedented vibsane-type diterpenes, named cyclovibsanin A, 15-Omethylcyclovibsanin A, 15-O-methylcyclovibsanin B, and 3-hydroxy-15-O-methylcyclovibsanin A, were isolated from the leaves of Viburnum awabuki. Their unique tricyclo[6.3.2.00,0]tridecane structures and plausible biosynthesis of cyclovibsanins are discussed here.

Four cell membrane-permeant derivatives of polyaza macrocyclic ligands, including acetoxymethyl (AM) and pivaloyloxymethyl (POM) esters of 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetrakis(ethyl methylenephosphonate) (DOTPME) and 1,4,7-triazacyclononane- 1,4,7-tris(ethyl methylenephosphonate) (NOTPME), were prepared as model systems for the detection of intracellular ions by 31P NMR spectroscopy. Preliminary results on isolated perfused rat hearts suggest that such ligands may be useful for monitoring intracellular levels of Ca2+ and Mg2+.