Stereocontrolled Synthesis of 2S,3R-(3)-Piperidinyl Glycine and 2S,4S-(3)-Piperidinyl Alanine: Medicinally Relevant Constrained Cyclic Amino Acids
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Abstract The stereocontrolled syntheses of 2S,3R-(3)-piperidinyl glycine hydrochloride and 2S,4S-(3)-piperidinyl alanine hydrochloride are described. These conformationally constrained α,γ- and α,δ-diamino acids were obtained via the stereoselective allylation of N–Cbz aspartate and glutamate diesters, respectively, followed by the intramolecular cyclization to form the piperidine ring. Orthogonally protected intermediates enabled late-stage diversification. Final deprotections afforded the target amino acids in high yields. The combination of the natural α-amino acid fragment and the basic piperidine unit in 3-piperidinyl glycine and alanine reveals the embedded frameworks of l-ornithine and l-lysine, making them peripheral or inserted components within structures of bioactive compounds of value for drug optimization and development.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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 it