Efficient synthesis of the 2-aminoimidazolium-bridged diguanosyl intermediate for nonenzymatic primer extension
Bibliographic record
Abstract
Nonenzymatic genome replication has yet to be demonstrated experimentally. Recently, studies on the nonenzymatic primer extension mechanism mediated by nucleoside 5′-monophosphates (NMPs) activated with 2-aminoimidazole (2AI) have revealed that imidazolium-bridged dinucleotide intermediates (N*N) are responsible for the bulk of the chemical copying process. As a result, an efficacious synthetic pathway for producing these substrates is desirable. Standard dehydrative redox reaction between NMPs and 2AI can produce N*N in high yields for all homodimers, apart from riboguanosine 5′-monophosphate. Here, we report a vastly improved methodology for the preparation of G*G, by the introduction of a simple reverse-phase cation exchange step to increase the solubility of the mononucleotide. Our approach is more efficient, cost-effective, less time-consuming, and has better atom economy than the currently established methodology for this important molecule in primer extension studies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".