Ammonium Chloride‐Promoted Rapid Synthesis of Monosubstituted Ureas under Microwave Irradiation
Bibliographic record
Abstract
Abstract Monosubstituted ureas are important scaffolds in organic chemistry. They appear in various biologically active compounds and serve as versatile precursors in synthesis. Monosubstituted ureas were originally prepared using toxic and hazardous phosgene equivalents. Modern methods include transamidation of urea and nucleophilic addition to cyanate salts, both of which suffer from a narrow substrate scope due to the need for a strong acid and prolonged reaction times. We hereby report that ammonium chloride can promote the reaction between amines and potassium cyanate to generate monosubstituted ureas in water. This method proceeds rapidly under microwave irradiation and tolerates a broad range of functional groups. Unlike previous strategies, it is compatible with other nucleophiles, acid‐labile moieties, and most of the common protecting groups. The products precipitate out of solution, allowing facile isolation without column chromatography.
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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 | 0.000 | 0.001 |
| 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) | 0.001 | 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".