Photo-Uncaging by C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Bond Cleavage Restores β-Lapachone Activity
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Bibliographic record
Abstract
β-Lapachone is an ortho -naphthoquinone natural product with significant antiproliferative activity but suffers from adverse systemic toxicity. The use of photoremovable protecting groups to covalently inactivate a substrate and then enable controllable release with light in a spatiotemporal manner is an attractive prodrug strategy to limit toxicity. However, visible light-activatable photocages are nearly exclusively enabled by linkages to nucleophilic functional sites such as alcohols, amines, thiols, phosphates, and sulfonates. Herein, we report covalent inactivation of the electrophilic quinone moiety of β-lapachone via a C(sp 3 )–C(sp 3 ) bond to a coumarin photocage. In contrast to β-lapachone, the designed prodrug remained intact in human whole blood and did not induce methemoglobinemia in the dark. Under light activation, the C–C bond cleaves to release the active quinone, recovering its biological activity when evaluated against the enzyme NQO1 and human cancer cells. Investigations into this report of a C(sp 3 )–C(sp 3 ) photoinduced bond cleavage suggest a nontraditional, radical-based mechanism of release beginning with an initial charge-transfer excited state. Additionally, caging and release of the isomeric para -quinone, α-lapachone, are demonstrated. As such, we describe a photocaging strategy for the pair of quinones and report a unique light-induced cleavage of a C–C bond. We envision that this photocage strategy can be extended to quinones beyond β- and α-lapachone, thus expanding the chemical toolbox of photocaged compounds.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.003 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 it