Synthesis and Structure‐Driven Acid‐Catalyzed Degradation of Benzoic Cyclic Acetal‐Labeled PEG Precursors toward Shell‐Sheddable PLA Block Copolymer Synthesis
Bibliographic record
Abstract
Abstract The synthesis of acid‐degradable poly(ethylene glycol) (PEG) precursors labeled with benzoic cyclic acetal (BzCA) is reported. To get an insight into their acid‐catalyzed hydrolysis, three precursors are designed with spacers exhibiting different inductive effects between PEG and BzCA linkage. The 1H‐NMR analysis confirms the order of increasing acid‐catalyzed hydrolysis to be ether > ester oxygen > ester carbonyl, which can be attributed to their ability to stabilize benzylic carbocation intermediates formed during hydrolysis. The formed precursors tend to be stable under a tin‐catalyzed condition for ring opening polymerization of lactide (LA), thus enabling the synthesis of well‐controlled acid‐degradable PEG‐based PLA block copolymers labeled with BzCA linkage at the block junction. When being exposed to acidic pH, the copolymers degrade through the cleavage of the junction BzCA linkages. These results guide the design principle of acid‐degradable shell‐sheddable BzCA‐bearing block copolymers for control over their acid‐catalyzed degradation and potentially drug release kinetics.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".