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Record W2073830260 · doi:10.1002/jhet.5570410521

Isolation and characterization of a novel tetrahydro‐[2,2′]bipyrrolyl dimer as an impurity from a knorr reaction

2004· article· en· W2073830260 on OpenAlex

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.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.

Bibliographic record

VenueJournal of Heterocyclic Chemistry · 2004
Typearticle
Languageen
FieldChemistry
TopicSynthesis and Characterization of Pyrroles
Canadian institutionsDalhousie University
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsChemistryDimerYield (engineering)ImpurityDissolutionZincCarboxylateOrganic chemistryCombinatorial chemistry

Abstract

fetched live from OpenAlex

Abstract A novel dimer, tetraethyl 2,2′,3,3′‐tetramethyl‐1,1′,2,2′‐tetrahydro‐4 H ,4′ H ‐2,2′‐bipyrrolyl‐5,5,5′,5′‐tetracarboxylate, has been isolated as an impurity (0.4% yield) from a Knorr reaction for the synthesis of ethyl 3,5‐dimethylpyrrole‐2‐carboxylate from 2,4‐pentanedione and diethyl oximinomalonate in a dissolving zinc reduction. The solid‐state structure of this novel dimer was determined by X‐ray crystallography. Knorr reactions typically rely upon the requisite pyrrole being the only water‐insoluble crystalline material present in the reaction mixture, and so work‐up and purification procedures for Knorr reactions should be monitored carefully given the water‐insolubility of this dimer. Investigations regarding mechanistic implications and reductive dimerization are underway.

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 categoriesnone
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 score0.013
Threshold uncertainty score0.821

Codex and Gemma teacher scores by category

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

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 head0.010
GPT teacher head0.234
Teacher spread0.224 · 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