Dibenzoate esters of <i>cis</i>-tetralin-2,3-diol as analogs of (–)-epigallocatechin gallate: synthesis and crystal structure of anticancer drug candidates
Bibliographic record
Abstract
(−)-Epigallocatechin gallate (EGCG), the main component of green tea extract, displays multiple biological activities. However, it cannot be used as a drug due to its low cellular absorption, instability and metabolic degradation. Therefore, there is a need to provide analogs that can overcome the limitations of EGCG. In this work, six synthetic analogs of EGCG sharing a common tetralindiol dibenzoate core were synthesized and fully characterized by 1 H NMR, 13 C NMR, HRMS and IR spectroscopies, and X-ray crystallography. These are (2 R ,3 S )-1,2,3,4-tetrahydronaphthalene-2,3-diyl bis[3,4,5-tris(benzyloxy)benzoate], C 66 H 56 O 10 , and the analogous esters bis(3,4,5-trimethoxybenzoate), C 30 H 32 O 10 , bis(3,4,5-trifluorobenzoate), C 24 H 14 F 6 O 4 , bis[4-(benzyloxy)benzoate], C 38 H 32 O 6 , bis(4-methoxybenzoate), C 26 H 24 O 6 , and bis(2,4,6-trifluorobenzoate), C 24 H 14 F 6 O 4 . Structural analysis revealed that the molecular shapes of these dibenzoate esters of tetralindiol are significantly different from that of previously reported dimandelate esters or monobenzoate esters, as the acid moieties extend far from the bicyclic system without folding back over the tetralin fragment. Compounds with small fluorine substituents take a V-shape, whereas larger methoxy and benzyloxy groups determine the formation of an L-shape or a cavity. Intermolecular interactions are dominated by π–π stacking and C—H...π interactions involving the arene rings in the benzoate fragment and the arene ring in the tetrahydronaphthalene moiety. All six crystal structures are determined in centrosymmetric space groups (either P -1, P 2 1 / n , C 2/ c or I 2/ a ).
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".