Synthesis of A Fluorescent PNA Monomer Containing 5-((9<b> <i>H</i> </b>-Fluoren-2-YL)Ethynyl)Uracil
Bibliographic record
Abstract
Pyrimidine nucleobases bearing 5-phenylethynyl substitution represent compact and intrinsically fluorescent nucleobases. Such nucleobases are capable of selective recognition of a complementary base and may fluorimetrically report on hybridization events. Our past work has demonstrated that the fluorescence of 5-phenylethynyluracils is sensitive to substitution on the phenyl ring, however these are relatively weak fluorophores. We currently are pursuing the functionalization of the phenyl group of these modified nucleobases in order to further improve their fluorescence response, increase their aqueous solubility and stabilize hybrids formed with complementary nucleic acids. As an example of this work, we have synthesized the 5-((9H-fluoren-2-yl)ethynyl)uracil PNA monomer that will be incorporated into oligomers using Fmoc-based chemistry. Initial evaluation of the fluorescence of the 5-((9H-fluoren-2-yl)ethynyl)uracil derivative shows that the fluorescence intensity is approximately 50 times greater than a similar 5-phenylethynyluracil derivative when under identical conditions.
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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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".