Zn(OAc)2•2H2O- Catalyzed Synthesis of Chromeno[2,3-d] Pyrimidinones under Solvent-free Conditions
Bibliographic record
Abstract
Due to their high synthetic efficiency, multi-component reactions (MCRs) have shown to be extraordinarily effective at producing compounds in a single synthetic operation. The chromeno[2,3-d] pyrimidine moieties represent important building blocks in synthetic bioactive compounds. The reaction of barbituric acid, aldehydes, and cyclohexane-1,3-diones in the presence of zinc acetate (5 mol%) under neat conditions at 70 0C, yielded a facile and one-pot synthesis of corresponding chromeno[2,3-d]pyrimidineones. Thirteen compounds containing neutral, withdrawing and electron donating groups (H, NO2, -CN, -Cl; -OH, -CH3 and -OCH3) were synthesized in good, isolated yields ranging from 78-91%. The successful involvement of o-, m-, and p- substituted nitro benzaldehydes suggested that steric hindrance had no effect. All of the synthesized compounds are well-known, and this process is unique in that it makes use of zinc acetate, an accessible, low-cost Lewis acid catalyst.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 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 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".