The solid-state structures of (-)-scopolamine free base, (-)-scopolamine methobromide, (-)-scopolamine hydrobromide trihydrate, and of the pseudopolymorphic forms of (-)-scopolamine hydrochloride anhydrate and 1.66hydrate
Bibliographic record
Abstract
(-)-Scopolamine hydrochloride anhydrate gives crystals belonging to the orthorhombic space group P2 1 2 1 2 1 and at 293(2) K: a = 7.097(2), b = 10.686(2), c = 22.623(2) Å, V = 1715.7(6) Å 3 , Z = 4, R(F) = 0.039, and R w (F) = 0.053. (-)-Scopolamine hydrochloride 1.66hydrate yields crystals belonging to the tetragonal space group P4 3 2 1 2 and at 293(2) K: a = b = 11.843(6), c = 26.211(4) Å, V = 3676(3) Å 3 , Z = 8, R(F) = 0.047, and R w (F 2 ) = 0.135. (-)-Scopolamine methobromide affords crystals belonging to the orthorhombic space group P2 1 2 1 2 1 and at 293(2) K: a = 7.0403(8), b = 10.926(2), c = 23.364(5) Å, V = 1797.2(6) Å 3 , Z = 4, R(F) = 0.039, and R w (F) = 0.052. The two hydrochloride pseudopolymorphs were isostructural to the corresponding two hydrobromide analogues. Both hydrohalide hydrated crystals have a water molecule occupying a general position of symmetry, and another water molecule occupying a special position of C 2 -rotation symmetry. The hydrated hydrochloride salt also had an additional 0.322(17) partial occupancy water molecule (absent in the hydrobromide sesquihydrate) occupying another special position of C 2 -rotation symmetry, i.e., the extra water molecule occupied the special position in statistically ca. one-third of the unit-cells to give a total hydrate stoichiometry of 1.66 molecules of water. While the two hydrohalide anhydrates exhibited extended tropate ester conformations (phenyl-ring antiperiplanar to oxirane moiety) vs. compact conformations (phenyl-ring near the scopine underside) for the two hydrated hydrohalides, all four displayed other common structural features: axial N-methyl stereochemistry, antiperiplanar methylol oxygen/aromatic C(ipso) relationships, and phenyl-ring eclipsing of the C(alpha)-H bond. The CPMAS 13 C NMR spectrum of (-)-scopolamine hydrobromide "trihydrate" shows it to be a conglomerate of (-)-scopolamine hydrobromide sesquihydrate plus two or more hydrated species (three ca. equal intensity carbonyl signals at 5.0 kHz spin-rate). High-speed rotor spinning (e.g., ca. 10 kHz and higher) causes a temperature-induced phase-transition to yield only the sesquihydrate form. The same transformation was noted with a 18 K rotor-temperature increase and an invariant 5.0 kHz spin-rate. The sesquihydrate spectrum remained after spin-rate decrease to 5.0 kHz, but the three component mixture 5.0 kHz spectrum was regenerated after three weeks sample storage within the capped rotor. The (-)-scopolamine free base crystalline melt CPMAS spectrum also shows a mixture of at least three hydrated species.Key words: stereochemistry, X-ray crystallography, solid-state NMR, CPMAS, anticholinergic.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".