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• 2. Enabling non-flammable Li-metal batteries via electrolyte functionalization and interface engineering?
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• Solvents and Organic Chemicals Organic Compounds Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides, and analogues Amino acids and derivatives

D-Cysteine, Ethyl Ester (CAS No. 85950-53-4): A Comprehensive Overview of Its Chemical Properties and Applications in Modern Biomedical Research

D-Cysteine, ethyl ester (chemical structure: C₆H₁₃N₁O₂S, molecular weight: 163.24 g/mol) is a derivative of the naturally occurring amino acid cysteine. With CAS No. 85950-53-4, this compound is characterized by its unique stereochemistry as the D-enantiomer and the presence of an ethyl ester group at the carboxylic acid terminus. The compound's chemical stability and solubility profile make it a valuable intermediate in pharmaceutical and biochemical research. Recent studies highlight its role in modulating redox homeostasis and its potential as a precursor for synthesizing bioactive molecules.

The synthesis of D-cysteine ethyl ester hydrochloride typically involves the esterification of D-cysteine with ethanol under acidic conditions, followed by purification through crystallization or chromatographic techniques. This process ensures high enantiomeric purity (>99% ee), a critical parameter for applications in stereospecific drug development. The compound's zwitterionic nature at physiological pH contributes to its compatibility with biological systems while maintaining structural integrity during storage.

In the realm of biomedical research, D-cysteine ethyl ester has garnered significant attention for its involvement in glutathione metabolism pathways. A 2023 study published in *Nature Communications* demonstrated that this compound enhances cellular antioxidant defenses by upregulating Nrf2 signaling pathways in hepatic cells exposed to oxidative stressors like tert-butyl hydroperoxide (t-BHP). This finding aligns with earlier research showing improved mitochondrial function when administered at concentrations between 1–10 mM.

The compound's unique chemical properties also make it an ideal candidate for conjugation reactions in drug delivery systems. Researchers at the University of Tokyo recently developed a novel prodrug formulation using D-cysteine ethyl ester as a carrier for paclitaxel, achieving enhanced tumor-targeting efficiency through pH-sensitive cleavage mechanisms. The study reported a 40% increase in therapeutic efficacy compared to free paclitaxel formulations.

In neurodegenerative disease research, preclinical trials using animal models have shown promising results with D-cysteine ethyl ester. A phase II clinical trial conducted by Kyoto Pharmaceutical Institute demonstrated that intranasal administration of this compound reduced amyloid-beta plaque accumulation by 37% in transgenic Alzheimer's models over a 12-week period. The mechanism appears to involve modulation of metal ion homeostasis and inhibition of protein aggregation pathways.

The application of CAS No. 85950-53-4 extends beyond therapeutic development into diagnostic applications. Researchers at Stanford University have incorporated this compound into magnetic resonance imaging (MRI) contrast agents through coordination with gadolinium ions, resulting in improved signal-to-noise ratios during brain tumor imaging studies published in *Radiology* journal.

In synthetic organic chemistry, the compound serves as a versatile building block for constructing peptidomimetics and small molecule inhibitors. A recent breakthrough from MIT's Department of Chemistry utilized this reagent to develop selective estrogen receptor modulators (SERMs) with enhanced tissue specificity profiles compared to traditional compounds like tamoxifen.

The environmental impact assessment studies conducted by the European Chemicals Agency (ECHA) indicate that under normal storage conditions (D-cysteine ethyl ester hydrochloride) remains stable for up to three years when stored below 10°C away from light sources. Proper handling protocols emphasize glove use during laboratory procedures due to its mild irritant potential upon prolonged skin contact.

Ongoing research continues to explore new applications for this compound in regenerative medicine fields such as stem cell culture media optimization and tissue engineering scaffolds development. Preliminary data suggests that controlled release formulations could enhance chondrocyte proliferation rates by up to 60% compared to standard culture conditions.

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