Synthesis of phosphoramidites of isoGNA, an isomer of glycerol nucleic acid.

IsoGNA, an isomer of glycerol nucleic acid GNA, is a flexible (acyclic) nucleic acid with bases directly attached to its linear backbone. IsoGNA exhibits (limited) base-pairing properties which are unique compared to other known flexible nucleic acids. Herein, we report on the details of the preparation of isoGNA phosphoramidites and an alternative route for the synthesis of the adenine derivative. The synthetic improvements described here enable an easy access to isoGNA and allows for the further exploration of this structural unit in oligonucleotide chemistry thereby spurring investigations of its usefulness and applicability.

Exploratory experiments on the chemistry of the "glyoxylate scenario": formation of ketosugars from dihydroxyfumarate.

In the context of a "glyoxylate scenario" of primordial metabolism, the reactions of dihydroxyfumarate (DHF) with reactive small molecule aldehydes (e.g., glyoxylate, formaldehyde, glycolaldehyde, and glyceraldehyde) in water were investigated and shown to form dihydroxyacetone, tetrulose, and the two pentuloses, with almost quantitative conversion. The practically clean and selective formation of ketoses in these reactions, with no detectable admixture of aldoses, stands in stark contrast to the formose reaction, where a complex mixture of linear and branched aldoses and ketoses are produced. These results suggest that the reaction of DHF with aldehydes could constitute a reasonable pathway for the formation of carbohydrates and allow for alternative potential prebiotic scenarios to the formose reaction to be considered.