Bibliographic record
Abstract
image [680‐15‐9] C 3 H 3 F 3 O 4 S (MW 192.11) InChI = 1S/C3H3F3O4S/c1‐10‐2(7)3(4,5)11(6,8)9/h1H3 InChIKey = GQJCAQADCPTHKN‐UHFFFAOYSA‐N (trifluoromethyl transfer reagent; nucleophilic trifluoromethylation of halides; difluorocarbene source; gem ‐difluorocyclopropanation; radical addition to alkenes) Alternative Name(s): difluoro(fluorosulfonyl)acetic acid methyl ester, MDFA. Physical Data: fp 47 °C; bp 117–118 °C; d 1.509 g mL −1 at 25 °C. Form Supplied in: liquid; commercially available; colorless to yellow. Solubility: soluble in DMF, NMP, EtCN, MeCN, THF, and MeOH. Preparation and Purification: the title reagent is prepared by first reacting difluoro(fluorosulfonyl)acetic acid with silver oxide. To a stirred solution of difluoro(fluorosulfonyl)acetic acid (2 equiv) in diethyl ether, silver oxide (1 equiv) is added slowly. The mixture protected from light is stirred for 15 h at room temperature. The resulting silver salt is filtered and dried under reduced pressure. The silver salt is then reacted with methyl iodide (1.3 equiv). The reaction mixture is protected from light and warmed to room temperature over 24 h. Methyl 2,2‐difluoro‐2‐(fluorosulfonyl)acetate is obtained in a 63% yield after distillation. 1 Handling, Storage, and Precautions: it should be stored in a closed container in a dark, dry, cool (2–8 °C), and well‐ventilated place. It should be handled in a well‐ventilated area and appropriate personal protective equipment (PPE) should be worn to avoid inhalation, ingestion or skin contact.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.039 | 0.015 |
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 source (direct Gemma or distilled Codex), 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".