A revised synthesis of 6-alkoxy-2-aminopurines with late-stage convergence allowing for increased molecular complexity
Bibliographic record
Abstract
6-alkoxy-2-aminopurine derivatives are potent inhibitors of Cyclin Dependent Kinases (CDKs), with some selectivity towards CDK2 and thus have potential as cancer therapeutics. Development of these inhibitors for targeting CDK2-cyclin A/E complexes has previously involved a thorough investigation of structure activity relationships of the C 2 amine moiety. However, the established synthesis of these compounds, which uses the alcohol reagent as solvent, limits the complexity of the O 6 functionality which is required for more selective targeting. Herein we report an improved and refocused synthesis of a model CDK2 inhibitor (NU6247), affording convenient access to inhibitors with O 6 substituents whose parent alcohol is not amenable for use as solvent. This revised synthesis allows for a meaningful exploration of the O 6 position in this class of CDK2 inhibitors.
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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) | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.004 |
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".