Parallel Synthesis of Tri- and Tetrasubstituted Ureas from Carbamoyl Imidazolium Salts
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Bibliographic record
Abstract
A method for producing tri- and tetrasubstituted ureas from carbamoyl imidazolium salts is presented. Carbamoyl imidazolium salts are prepared from the reaction of N,N carbonyldiimidazole (CDI) with secondary amines, followed by alkylation with iodomethane. These stable salts can be stored for extended periods and are effective electrophilic carbamoylation reagents. Primary and secondary amines add to carbamoyl imidazolium salts at room temperature to give tri- and tetrasubstituted ureas in excellent yields. This reaction was used to synthesize ureas using both liquid-liquid extraction and solid-phase extraction (cation exchange) purification techniques. Liquid-liquid extraction affords the product ureas more cleanly than cationic exchange. A series of urea compounds were synthesized using parallel synthesis techniques in high yields and with suitable purity for routine in vitro biological tests. These studies validate the utility of carbamoyl imidazolium salts as useful building blocks for combinatorial library synthesis.
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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) | 0.001 | 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) | 0.003 | 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