Reactivity of nucleosides with a hydroxyl radical in non-aqueous medium

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

Solid-phase synthesis of electrophilic oligodeoxynucleotides (ODNs) was achieved using dimethyl-Dmoc (dM-Dmoc) as amino protecting group. Due to the high steric hindrance of the 2-(propan-2-ylidene)-1,3-dithiane side product from deprotection, the use of excess nucleophilic scavengers such as aniline to prevent Michael addition of the side product to the deprotected ODN during ODN cleavage and deprotection was no longer needed. The improved technology was demonstrated by the synthesis and characterization of five ODNs including three modified ones. The modified ODNs contained the electrophilic groups ethyl ester, α-chloroamide, and thioester. Using the technology, the sensitive groups can be installed at any location within the ODN sequences without using any sequence- or functionality-specific conditions and procedures.

A Time-Resolved Study on the Reactivity of Alcoholic Drinks with the Hydroxyl Radical

Reactive oxygen species (ROS) can provoke damage to cells, where their concentrations are regulated by antioxidants. As the hydroxyl radical (•OH) is the most oxidizing ROS, we have focused our attention on the use of a mechanistically based time-resolved methodology, such as laser flash photolysis, to determine the relative reactivity of alcoholic beverages towards •OH as an indicator of their antioxidant potential. The selected drinks were of two different origins: (i) those derived from grapes such as red wine, white wine, white vermouth, marc and brandy and (ii) spirits not derived from grapes: triple sec, gin, whisky, and rum. Initially, we determined the quenching rate constant of ethanol with •OH and then we explored the reactivity of the different beverages, which was higher than expected based on their alcoholic content. This can be attributed to the presence of antioxidants and was especially remarkable for the grape-derived drinks.

Synthesis of Oligodeoxynucleotides Containing Electrophilic Groups

By use of 1,3-dithian-2-yl-methoxycarbonyl (Dmoc) as a protecting group and linker for oligodeoxynucleotide (ODN) synthesis, deprotection and cleavage are achieved under non-nucleophilic oxidative conditions. The nucleophile-sensitive thioester and α-chloroacetyl groups are conveniently incorporated into ODN sequences. The technology could be universally useful for electrophilic ODN synthesis.