Bibliographic record
Abstract
The objective of this work was to synthesize novel aromatic compounds based on tetraphenylporphyrins. These compounds are potential photosensitizers for use in photodynamic therapy. Several approaches were employed towards this goal. Numerous tetraphenylporphyrins possessing a variety of substituents were synthesized, characterized and used as starting materials to prepare the analogous diol chlorins via the patented osmium tetroxide oxidation. Compounds possessing hydroxy, methoxy, alkyl and halogen substituents were prepared. Studies involving the syntheses of these variously substituted meso-tetraphenyl- vic-2,3-dihydroxy-2,3-chlorins and analysis of their in vitro biological test results are presented and discussed. A number of these compounds appear very promising, particularly diphenyl-2,3-dihydroxy-2,3-chlorin (125) which had an LD50 value of 0.0024 µM - 450 times as potent as the commercially available standard Photofrin. [Figure.] Attempts to improve the oxidation reaction via the reversible modification of starting materials and the use of other substrates as starting materials are also discussed. The use of electronically activated N-alkylated tetraphenylporphyrins as starting materials was attempted. This reaction was successful for N-methyl TPP (131) but failed when N-phenyl TPP (132) was employed. Additionally, the osmium tetroxide mediated oxidation of octaethyltetraphenylporphyrin (137) was attempted. (meso-Tetraphenyl-2,3-dihydroxy-2,3-chlorinato)nickel (106) can be oxidized to form (meso-tetraphenyl- 2,3-dialdehyde-2,3-secochlorinato)nickel (145). An investigation of the reactivity of this novel compound (145) is presented. A wide variety of reactions were performed including reactions with acids, bases, alcohols, amines and reducing agents. Over 30 interesting and novel compounds were synthesized from nickel bisaldehyde secochlorin (145) such as the doubly cyclized diketo product (182) from reaction of (145) with TFA followed by base, and the unsubstituted secochlorin (191) from the decarbonylation of (145) with Wilkinson's catalyst. [Figures.] Finally, a relatively unexplored field of porphyrin research was investigated. Studies probed the reactivity of both tetra- and diphenylporphyrins in a number of different 1,3-dipolar cycloaddition reactions. Although this initial investigation was met with limited success overall, reactions with mesitaldehyde oxide, tetracyanoethylene oxide (TCNEO) and diazomethane were fruitful, forming products (226), (213) and (223) respectively. [Figures.]
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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) | 0.009 | 0.002 |
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".