Concurrent Phosphite Oxidation and Adenosine Phosphorylation Under Prebiotic Evaporative Conditions

Reduced oxidation state phosphorus species, such as phosphite, have been proposed as more soluble phosphorus sources, yet their role in phosphorylation chemistry remains incompletely understood. Here, we investigate the concurrent oxidation of phosphite and phosphorylation/phosphonylation of adenosine under prebiotically plausible conditions. Using aqueous reaction systems containing phosphite, urea, hydrogen peroxide (H₂O₂), and adenosine, we show synthesis of adenosine phosphates, adenosine phosphites, adenosyl adenosine phosphate, and trace amounts of ADP (adenosine diphosphate). Reactions conducted under warm evaporating pool conditions (75-78 °C) yielded up to 73% total adenosine-phosphorus products, while wet-dry cycling experiments produced up to 60%, with a preference toward adenosine phosphate formation. Product distributions were characterized using ³¹P and ¹H NMR spectroscopy and confirmed by comparison with authentic standards. Our results demonstrate that phosphite oxidation can occur concurrently with phosphorus incorporation into adenosine under prebiotically plausible aqueous conditions. Urea likely facilitates dehydration and condensation processes, consistent with its previously recognized role in prebiotic phosphorylation chemistry. These findings demonstrate that phosphite oxidation and the formation of biologically relevant organophosphorus compounds can occur concurrently under prebiotically plausible conditions. The coupling of oxidation, phosphorylation, and condensation reactions demonstrates how simple prebiotic starting materials can be transformed into more complex phosphorus-containing organic products relevant to the emergence of nucleotide chemistry.