Relationships between step and cumulative PMI and E-factors: implications on estimating material efficiency with respect to charting synthesis optimization strategies
Bibliographic record
Abstract
Abstract This report describes mathematical relationships between step and cumulative process mass intensities (PMIs) for synthesis plans, and analogous parameters applied to E-factors. It is shown that both step E-factors and step PMIs are not additive for synthesis plans. It is also shown that a recursive calculation of cumulative PMIs from step PMIs is a rapid method of determining overall PMIs for synthesis plans, though cumulative PMIs are not sufficiently informative as step PMIs or step E-factors to identify bottlenecks in synthesis plans. Illustrations on the use of these metrics to track the material efficiency of published synthesis plans for the pharmaceutical, apixaban, are given as a template example. Advantages and disadvantages of each metric are discussed. A general algorithm to select the most promising candidate synthesis plans considered at the design stage for a given molecular target that most likely satisfy “green” material efficiency criteria is also presented.
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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 | 0.006 | 0.037 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".