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Record W2144259831 · doi:10.1139/v02-175

Structural and conformational studies of 5-(1<i>H</i>-pyrrol-2-ylmethylene)-substituted imidazolidine-2,4-diones and thiazolidine-2,4-diones

2002· article· en· W2144259831 on OpenAlex
Alfonso de Dios, Marı́a Luz de la Puente, Alfonso Rivera‐Sagredo, Juan F. Espinosa

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.

venuePublished in a venue whose home country is Canada.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueCanadian Journal of Chemistry · 2002
Typearticle
Languageen
FieldChemistry
TopicSynthesis of heterocyclic compounds
Canadian institutionsnot available
Fundersnot available
KeywordsChemistryConformational isomerismImidazolidineThiazolidineHydantoinIntramolecular forceSubstituentStereochemistryNuclear magnetic resonance spectroscopyHydrogen bondMoleculeProton NMRCis–trans isomerismOrganic chemistry

Abstract

fetched live from OpenAlex

Some imidazolidine-2,4-dione (hydantoin) and thiazolidine-2,4-dione (TZD) derivatives with a 1H-pyrrol-2-ylmethylene substituent at the 5-position (1–8) have been synthesized via an aldol condensation reaction. A mixture of Z- and E- stereoisomers was obtained, as confirmed by HPLC and NMR studies. Assignment of the stereochemistry was achieved through chemical shift knowledge, NOE, and 3 J H,C data. The conformation of the molecules depends on the configuration at the double bond. While the (NH,C cis) form is the most stable conformer for the E-isomer, the (NH,C trans) form is the preferred conformer for the Z-isomer. The temperature coefficients of the NH pyrrole protons reveal the existence of an intramolecular hydrogen bond for the E-isomers.Key words: hydantoin, TZD, NMR spectroscopy, conformational analysis, temperature coefficient.

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.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Insufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.033
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0000.001
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

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.

Opus teacher head0.034
GPT teacher head0.238
Teacher spread0.204 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it