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Record W1980150896 · doi:10.1021/np034005w

Methylation of Dihydroquercetin Acetates:  Synthesis of 5-<i>O</i>-Methyldihydroquercetin

2003· article· en· W1980150896 on OpenAlex
Eberhard Kiehlmann, Peter Slade

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.

Bibliographic record

VenueJournal of Natural Products · 2003
Typearticle
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicTraditional and Medicinal Uses of Annonaceae
Canadian institutionsSimon Fraser University
Fundersnot available
KeywordsChemistryDiazomethaneEtherKetoneCellulose triacetateMethylationOrganic chemistryMedicinal chemistryStereochemistry

Abstract

fetched live from OpenAlex

The major products of methylation of dihydroquercetin (1, dhq) with diazomethane have been identified as 7-O-methyldhq (9), 7,3'-di-O-methyldhq (10), 7,4'-di-O-methyldhq (11), and 7,3',4'-tri-O-methyldhq (2). With dhq 3,7,3',4'-tetraacetate (6), dhq 3,5,3',4'-tetraacetate (5), dhq 3,3',4'-triacetate (7), dhq 7,3',4'-triacetate (8), and dhq 3-acetate (4) the same reaction affords mainly 5-O-methyldhq 3,7,3',4'-tetraacetate (15), 7-O-methyldhq 3,5,3',4'-tetraacetate (13), 7-O-methyldhq 3,3',4'-triacetate (14), 5-O-methyldhq 7,3',4'-triacetate (25), and 7-O-methyldhq 3-acetate (12), respectively. The methylation of 8 is accompanied by intermolecular acetyl migration from phenolic oxygen to the hydroxy group of the heterocyclic ring. 5-O-Methyldhq (28) is accessible by deacetylation of 25. 5,7-Di-O-methyldhq (29), four known methyl ethers, 13 new and three known methyl ether acetates of dhq, and six new isomers with 2,3-cis stereochemistry were spectroscopically identified.

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)0.001
metaresearch head score (Gemma)0.002
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 score0.009
Threshold uncertainty score0.408

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
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 head0.009
GPT teacher head0.240
Teacher spread0.231 · 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