Synthesis and characterization of randomly 2,3-O-sulfoalkylated beta-cyclodextrins for use in chiral capillary electrophoresis
Bibliographic record
Abstract
Chiral separation of enantiomers is of vast significance in synthetic chemistry.Determining the enantiomeric purity of a product is necessary in the pharmaceutical industry.Recent studies in capillary electrokinetic chromatography (cEKC) have suggested that anionic cyclodextrins (CDs) are powerful chiral resolving agents.The purpose of this research was to synthesize a series of highly charged heptakis(randomly-2,3-O-sulfoalkyl)-P-CDs, characterize the CDs, and apply the CDs to chiral separations of aryl alcohols.The synthesis focused on the sulfobutylation of heptakis(6-O-methyl)-P-CD and heptakis(6-O-fert-butyldimethylsilyl)-P-CD as well as the sulfopropylation of heptakis(6-O-fert-butyldimethylsilyl)-P-CD.The degree o f sulfoalkylation of the final products was determined by hydrophilic interaction chromatography (HILIC) with a low temperature evaporative light scattering detector (LT-ELSD).The synthesis of heptakis(6-O-methyl)-P-CD was obtained by a lengthy protection/deprotection reaction scheme utilizing the acetylation of the secondary hydroxyl groups, with an overall yield of 43% in 5 steps.The sulfobutylation of heptakis(6-O-methyl)-P-CD and heptakis(6-Ofert-butyldimethylsilyl)-P-CD produced low degrees o f substitution (DS < 1.0).The sulfopropylation of heptakis(6-O-fert-butyldimethylsilyl)-P-CD in tetrahydrofuran (THF) resulted in much higher degree o f substitution, with DS of 3.3, 4.6, and 6.1, which increased with amount of added 18-crown-6 ether.Also, an increase in the DS (6.1 and 8.4) was observed when changing the solvent from THF to N,N-dimethylformamide.Chiral resolution studies of relevant aryl alcohols using potassium heptakis(randomly-iii 2,3-O-sulfopropyl)-P-CD (DS 8.4), potassium heptakis(2,3-di-O-methyl-6-Osulfopropyl)-P-CD (DS 4.5) and the single isomer potassium heptakis(2,3-di-O-methyl-6-O-sulfobutyl)-P-CD were performed.Resolution of the enantiomers of the aryl alcohols is dependent on the distance of the chiral center from the aromatic ring and the substituent on the secondary rim of the cyclodextrin.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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 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".