An Efficient Methodology for the Synthesis of 1-(Trimethylammoniummethyl)cyclohexaneacetic Acid Iodide: A Trimethylammonium Iodide Salt of Gabapentin
Bibliographic record
Abstract
The gabapentinoids pregabalin and gabapentin are structurally related to the inhibitory neurotransmitter γ -aminobutryic acid (GABA). These two agents, originally introduced as anticonvulsant (antepileptic) drugs, are now approved and commonly used in the treatment of neuropathic pain. Neuropathic pain is characteristically resistant to the analgesic actions of opioids and non-steroidal anti-inflammatory drugs. The accepted mechanism of action of gabapentinoids is based on their transport into neurons via a non-specific amino acid transporter where they bind with the alpha 2 delta subunit of voltage gated Ca 2+ channels. 1,2 It has also been shown that TRPV1 channels, which are present on nociceptive neurons and are opened by agonists such as capsaicin, 3–5 allow the permeation of small organic molecules such as local anesthetics. 6 Accordingly, it is possible that opening of TRPV1 channels may provide a means to deliver gabapentinoids to their intracellular site of action. This concept may constitute a more effective alternative than reliance on the amino acid transporter and it may selectively target the gabapentinoids to nociceptive neurons. To test whether gabapentinoids pass through TRPV1 channels, a charged analog of gabapentin could be used to replace all Na + and Ca 2+ ions in the extracellular fluid. For this reason, it was necessary to synthesize a quaternary salt of gabapentin 1. We now describe an efficient methodology for the synthesis of 1-(trimethylammoniummethyl)cyclohexaneacetic acid iodide (2) using a four-step reaction sequence free of time consuming chromatography in 81% overall isolated yield starting from gabapentin (see structures in Scheme 1).
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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 | 0.002 |
| 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) | 0.000 | 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".