10.1021/jm950803a
The research focuses on developing analogs of thymopentin, an immunomodulating drug with a short half-life in plasma, to enhance its stability while retaining its biological activity. Thymopentin (TP-5) is a pentapeptide with the sequence Arg-Lys-Aspartic Acid-Val-Tyrosine. The parent compound is known for its immunomodulatory properties but has a short half-life in plasma. This study aimed to develop analogs with improved stability while retaining activity. Hydrogen fluoride (HF), a strong acid (HF), is used in the final step to cleave the peptide from the resin and remove any remaining protecting groups, resulting in the final pseudopeptide analog. Ruthenium(IV) Oxide (RuO2), an oxidizing agent (RuO2), is used in combination with sodium periodate (NaIO4) to oxidize olefinic bonds in the synthesis of pseudopeptides, converting them to the desired ketone or acid products. The study concludes that while these modifications improved stability, they often came at the cost of reduced binding affinity, highlighting the trade-offs in designing analogs with both enhanced stability and retained biological activity.
Physiologic conditions affect toxicity of ingested industrial fluoride
10.1155/2013/439490
Richard Sauerheber investigates how physiological conditions, particularly calcium ion levels and pH, influence the toxicity of ingested industrial fluoride. The study calculates that blood fluoride concentrations causing lethal poisonings would significantly decrease calcium levels. It highlights that acute and chronic fluoride toxicity often involves altering calcium's chemical activity. Industrial fluorides, unlike natural calcium fluoride, are fully soluble and highly toxic. The research demonstrates that at stomach pH, fluoride primarily exists as hydrofluoric acid (HF), which is highly absorbable and corrosive. The study also discusses the chronic effects of fluoride, such as its accumulation in bones and potential harm to the heart, brain, and developing teeth. It criticizes the widespread practice of water fluoridation, arguing that it leads to various health issues and environmental concerns. The author concludes that adding industrial fluoride to drinking water is an ineffective and harmful public health policy, given the numerous adverse effects observed and the lack of substantial evidence supporting its dental benefits.
10.1021/jm00272a031
The research focuses on the synthesis and characterization of new chemical compounds with potential applications in medicinal chemistry. The primary purpose of the study is to develop and analyze novel compounds that may have therapeutic properties or serve as intermediates in the production of pharmaceuticals. The researchers synthesized compounds such as 2-fluoro-9-(p-D-ribofuranosyl)purine (2a) and 9-(2,3,5-tri-O-acetyl-α-D-ribofuranosyl)-2-fluoropurine (2b), using various chemical reagents and techniques. Key chemicals involved in the synthesis include Raney nickel, ethanol, hydrofluoric acid, sodium nitrite, and acetic anhydride, among others. The conclusions drawn from the study highlight the successful synthesis of the target compounds and their structural confirmation through analytical techniques. The research contributes to the field of medicinal chemistry by providing new compounds that can be further explored for their biological activities and potential applications in drug development.
10.1016/j.steroids.2011.05.014
The research focuses on the synthesis of pentadeuterated 5b-tetrahydrocorticosteroid monosulfates at the 3- and 21-positions. These compounds serve as internal standards for mass spectrometry assays in clinical and biochemical studies. The synthesis process involves several key steps and chemicals. Initially, the methylene groups adjacent to the 3-oxo group of 17,20:20,21-bismethylendioxy-5b-3-ketosteroids are perdeuterated using NaOD in CH3OD, followed by stereoselective reduction with NaBD4. Subsequently, hydroxy groups are sulfated using the sulfur trioxide–trimethylamine complex. Finally, the bismethylendioxy group is removed with hydrogen fluoride. The synthesized compounds are characterized by 1H NMR and ESI-MS, confirming their structures and isotopic purity. The availability of these deuterated internal standards enhances the accuracy and reliability of mass spectrometry analyses for tetrahydrocorticosteroid metabolites in biological fluids.
10.1007/BF00962755
The study investigates the fluorodeoxygenation of (R,S)- and (S)-proline using sulfur tetrafluoride in hydrogen fluoride to produce =-trifluoromethylpyrrolidine (-)-(I), aiming to explore the retention of optical activity and absolute configuration of the chiral =-carbon atom during this process. The authors obtained diastereomeric derivatives such as (+)-(IIA) to determine the optical purity of (-)-(I), which was found to be no less than 96%. The study also examines the stereochemistry of chromophoric derivatives like the nitrosoamine (+)-(III) and the chloroamine (-)-(IV), comparing their chiroptical characteristics with those of analogs such as l-nitroso-(S)-proline methyl ester (V) and l-chloro-(S)-proline methyl ester (VI). The results indicate that the absolute (S) configuration of the carbon chiral center is preserved during the fluorodeoxygenation of (S)-proline.
T, 
C. 
T+, 
Xn
T+:Very toxic;
