Concise and Efficient Synthesis of 2-Acetamido-2-deoxy-β-<scp>d</scp>-hexopyranosides of Diverse Aminosugars from 2-Acetamido-2-deoxy-β-<scp>d</scp>-glucose
Bibliographic record
Abstract
The furanose acetonide derivative 1 is readily prepared from 2-acetamido-2-deoxy-D-glucose on a large scale without the need for chromatography. Mesylation of 1 provides an efficient, concise, synthetic route to rare 2-acetamido-2-deoxy-beta-D-hexopyranosides (2 and 3) via the corresponding methyl 2-acetamido-2-deoxy-3-O-methanesulfonyl-beta-D-glucopyranoside and subsequent inversion of configuration by direct displacement or formation of a 3,4-epoxide. Opening of this epoxide by azide provided a direct route to methyl 2-acetamido-4-amino-2,4,6-trideoxy-beta-D-gulopyranoside 4. Benzylation of 1 followed by ring expansion to the glucopyranoside, deoxygenation at C-6, and subsequent displacement of a C-4 triflate permitted the synthesis of methyl 2-acetamido-4-amino-2,4,6-trideoxy-beta-D-galactopyranoside 5. Methyl 2-acetamido-2-deoxy-beta-D-glucopyranoside available from 1 in quantitative yield was readily converted to methyl 2-acetamido-2-deoxy-beta-D-galactopyranoside 6 (>60%) by inversion of configuration at C-4. Introduction of a lactyl substituent at C-3 of oxazoline 1 also provides a facile synthesis of the biologically important muramic acid beta-glycoside 7. An interesting reaction to convert 2-acetamido-2-deoxyhexopyranosides to the corresponding 2-deoxy-2-tetrazole is also reported.
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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 | 0.005 |
| 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 | 0.001 |
| Research integrity | 0.001 | 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".