Synthesis of 1‐(2‐deoxy‐β‐<scp>D</scp>‐ribofuranosyl)‐2,4‐ difluoro‐5‐(2‐halo‐1‐hydroxyethyl)benzenes and related derivatives: “thymine replacement” analogs of deoxythymidine for evaluation as antiviral and anticancer agents
Bibliographic record
Abstract
Abstract A group of unnatural 1‐(2‐deoxy‐β‐ D ‐ribofuranosyl)‐2,4‐difluorobenzenes having a variety of C‐5 substituents, designed as thymidine mimics, were synthesized for evaluation as antiviral and anticancer agents. The regiospecific addition of HOBr (generated from N ‐bromosuccinimide in aqueous dioxane) across the 5‐vinyl substituent ( 4 ) afforded the corresponding 5‐[‐CH(OH)CH 2 Br] product ( 5 ), whereas reaction of 4 with iodine in the presence of iodic acid (HOI) yielded the 5‐[CH(OH)CH 2 I] product ( 6 ). The related 5‐[‐CH(OH)CHX 2 (X = Br, I)] analogs ( 11 , 12 ) were similarly prepared from the ( E )‐5‐(2‐halovinyl) precursors ( 9 , 10 ). Treatment of the 5‐[‐CH(OH)CH 2 X (X = Br, I)] compounds ( 5 , 6 ) with NaOH in aqueous dioxane afforded the 5‐oxiranyl product ( 8 ). The 5‐[‐CH(OMe)CH 2 I] compound ( 7 ) was prepared by reaction of the 5‐vinyl compound (4) with ICl in MeOH (MeOI). This group of compounds ( 5 – 8 , 11 , 12 ) showed similar (marginal) activity against varicella‐zoster virus thymidine kinase positive (VZV/TK + ) and thymidine kinase deficient (VZV/TK – ) infected cells. Thus, the viral TK enzyme did not provide a gene therapeutic effect. This group of compounds, which were evaluated using a wide variety of antiviral assay systems [(herpes simplex virus HSV‐1, HSV‐2), varicella‐zoster virus (VZV), vaccinia virus, vesicular stomatitis, cytomegalovirus (CMV), and human immunodeficiency virus (HIV‐1, HIV‐2)], showed that these unnatural C‐aryl nucleoside mimics are inactive antiviral agents. Their failure to exhibit antiviral/anticancer activity could be due to the fact that they are not phosphorylated to the 5′‐monophosphate, or that incorporation of the active 5′‐triphosphate into DNA does not produce a cytotoxic effect, and/or that these C‐aryl nucleoside mimics do not act as inhibitors of thymidylate synthase, which may be required to produce a cytotoxic effect. Drug Dev. Res. 52:492–499, 2001. © 2001 Wiley‐Liss, Inc.
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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 | 0.000 | 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".