Expedient Multi-Step Synthesis of Organometallic Complexes of Tc and Re in High Effective Specific Activity. A New Platform for the Production of Molecular Imaging and Therapy Agents
Bibliographic record
Abstract
For over thirty years, instant labeling kits which involve no purification steps have been the only method used to prepare (99m)Tc radiopharmaceuticals for clinical studies. To address the limitations imposed by instant kits, which is hindering the development of molecularly targeted Tc- and Re-based imaging and therapy agents, a new strategy for the rapid multistep synthesis and purification of organometallic technetium-based molecular probes and corresponding rhenium-based therapeutic analogues was developed. Beginning with MO4(-) (M = (99m)Tc, (186/188)Re), the carbonyl precursor [M(CO)3(H2O)3](+) was synthesized in 3 min in quantitative yield in a microwave reactor. A dipicolyl ligand was added and the chelate complex was formed in high yield in 2 min using microwave heating at 150 degrees C. This was followed by a new purification strategy to remove unlabeled ligand which entailed using a copper resin/C18 solid phase extraction protocol giving the desired product in greater than 78% decay corrected yield (dcy). Conversion to the corresponding succinimidyl active ester was achieved following a 5 min microwave irradiation at 120 degrees C and C18 solid phase extraction purification in 60% dcy. A series of amides were prepared subsequently by microwave heating at 120 degrees C for 5 min producing the desired targets in greater than 86% dcy. The reported method represents a move away from traditional instant kits toward more versatile platform synthesis and purification technologies that are better suited for producing modern molecular imaging and therapy agents.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".