N-Isocyanates, N-Isothiocyanates and Their Masked/Blocked Derivatives: Synthesis and Reactivity
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
In contrast to <i>C</i>-substituted isocyanates which are frequently used reagents in synthesis, nitrogen-substituted isocyanates (<i>N</i>-isocyanates) remained a scientific curiosity in the literature for over a century. The amphoteric character of these reactive intermediates, which results in their propensity to dimerize, prevented the development of their full synthetic potential. In this review, the pioneering work that led to the development of reliable methods for their synthesis, established the existence of such species by spectroscopy, and allowed a delineation of their basic reactivity is presented. The high reactivity of these intermediates has been controlled through the use of masked precursors to regulate their concentration via a reversible equilibrium, a strategy which is also used in industrial processes utilizing <i>C</i>-isocyanates. This control led to the development of more complex reactions, including reaction cascades that allow the rapid synthesis of heterocycles possessing the N–N–C=O motif, which is widely present in agrochemicals and pharmaceuticals. This review covers the literature of <i>N</i>-isocyanates and their sulfur analogues, <i>N</i>-isothiocyanates, until April 2016. 1 Introduction 2 Formation of <i>N</i>-Isocyanates 2.1 Rearrangement of Carbamoyl Azides 2.2 Ring Opening of Heterocycles 2.3 Thermolysis of Hydrazine Derivatives 3 Formation of <i>N</i>-Isothiocyanates 4 Isolation and Observation 4.1 Isolation and Observation of <i>N</i>-Isothiocyanates 4.2 Isolation and Observation of <i>N</i>-Isocyanates 5 Reactivity 5.1 Reactivity of <i>N</i>-Isothiocyanates 5.2 Reactivity of <i>N</i>-Isocyanates 6 Conclusion
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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 | 0.001 | 0.004 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 it