The metal template effect on <i>O</i>-alkylation of tetrahydroxy[3.1.3.1]metacyclophane with 4-(chloromethyl)pyridine to afford tetrakis- [(4-pyridylmethyl)oxy][3.1.3.1]metacyclophanes and their conformational studies
Bibliographic record
Abstract
An attempted O-alkylation of the flexible macrocycle tetrahydroxy[3.1.3.1]metacyclophane (1) with 4-(chloromethyl) pyridine (2a) in the presence of NaH under THF reflux gave 1,3-di-O-substitution product distal-3a as a major product. In contrast, tetraol 1 was O-alkylated with 2a in the presence of Cs 2 CO 3 to afford a mixture of two conformers of tetra-O-alkylated product 4a in a ratio of 77:23 (1,4-alternate-4a:partial-cone-4a) in 95% yield. No formation of the cone conformer in the reaction of the tetraol 1 with 2a, in comparison with those with 2-(chloromethyl) pyridine (2b) or benzyl bromide (2c) in the presence of NaH or K 2 CO 3 , which predominantly afforded cone-conformer, might be attributable to the absence of contributions derived from cationN interactions as well as cationπ interactions. The latter effect might be much smaller because of the decreased π-density of the pyridine ring compared to that of the benzene ring. The structural characterization of these products in solution as well as solid state is also discussed.Key words: macrocycles, calixarenes, cyclophanes, [3.1.3.1]metacyclophanes, O-alkylation, conformation, crystal structure, cationN interaction.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".