New potential dendritic cores: Selective chemistry of dipentaerythritol
Bibliographic record
Abstract
Methods were developed to convert dipentaerythritol efficiently into di-O-benzylidene, di-O-cyclohexylidene, di-O-1-ethylpropylidene, and di-O-methylene diacetals. The known di-O-benzylidene acetal, considered to be a single isomer, was shown to be close to a statistical mixture of the cis,cis-, cis,trans-, and trans,trans-isomers. Structures were established by a combination of NMR spectroscopy and X-ray crystallography. Reaction of the di-O-benzylidene acetals with benzyl chloride and potassium hydroxide surprisingly gave good to excellent yields of the monobenzyl ethers. An explanation for this observation was advanced. The dibenzyl derivatives of the di-O-benzylidene acetals were formed by reaction of their dianions with benzyl bromide in DMF. Selective reduction of the di-O-benzylidene acetals with triethylsilane and boron trifluoride etherate gave 2',6'-di-O-benzyldipentaerythritol. A crown ether was formed in modest yield (12%) by reaction of the dianion of the di-O-methylene acetal with α,α'-dibromo-m-xylene in DMF. Key words: dipentaerythritol, pentaerythritol, acetals, dendrimer, selective benzylation, crown ether.
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How this classification was reachedexpand
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 | 0.000 | 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) | 0.006 | 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 teacher head, 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".