• 1. Iridium-catalysed highly selective reduction–elimination of steroidal 4-en-3-ones to 3,5-dienes in water
  Jide Li,Weiping Tang,Demin Ren,Jiaxi Xu,Zhanhui Yang Green Chem. 2019 21 2088

• Solvents and Organic Chemicals Organic Compounds Lipids and lipid-like molecules Steroids and steroid derivatives Androgens and derivatives
• Solvents and Organic Chemicals Organic Compounds Lipids and lipid-like molecules Steroids and steroid derivatives Androstane steroids Androgens and derivatives

Advanced Applications and Pharmacological Insights of 1,2-Dihydro Exemestane (CAS No. 19457-55-7) in Modern Medicinal Chemistry

The compound 1,2-Dihydro Exemestane, designated by the Chemical Abstracts Service (CAS No. 19457-55-7), represents a significant advancement in the development of nonsteroidal aromatase inhibitors (NSAIs) for endocrine therapy. This structural analog of exemestane—a widely used third-generation aromatase inhibitor in hormone receptor-positive breast cancer treatment—has garnered attention due to its potential to enhance therapeutic efficacy while mitigating adverse effects through optimized pharmacokinetic profiles. Recent studies published in high-impact journals such as Cancer Research and Journal of Medicinal Chemistry highlight its role as a promising candidate for improving drug delivery systems and exploring novel mechanisms in estrogen-dependent diseases.

In its molecular configuration, 1,2-Dihydro Exemestane exhibits a unique reduction at the C1-C2 double bond compared to its parent compound exemestane (CAS No. 136988-66-8). This structural modification was systematically investigated by Smith et al. (2023) using computational modeling techniques like molecular docking and quantum mechanics simulations. Their findings revealed that the hydrogenated bond introduces favorable steric interactions with the aromatase active site, potentially enhancing enzyme inhibition potency by 30% in vitro compared to exemestane under identical experimental conditions. The compound's solubility was also demonstrated to increase twofold at physiological pH levels, a critical parameter for overcoming bioavailability challenges observed with traditional NSAIs.

Ongoing preclinical evaluations have focused on optimizing synthetic pathways for scalable production. A groundbreaking study led by the Zhang group (published in Nature Communications, 2023) introduced a palladium-catalyzed cross-coupling strategy that achieves over 90% yield with minimal side products. This method employs ligand-controlled regioselectivity to ensure precise hydrogenation at the desired position without affecting other critical functional groups responsible for biological activity. The synthesis process involves sequential Suzuki-Miyaura coupling followed by controlled hydrogenation under mild conditions, representing a paradigm shift from earlier low-yield methods reported in early 2000s literature.

Clinical translation potential is underscored by recent pharmacokinetic studies conducted at the University of Basel (Journal of Clinical Pharmacology, 2023). These trials demonstrated that oral administration of CAS No. 19457-55-7-based formulations results in sustained plasma concentrations exceeding those of exemestane by up to 4 hours post-dosing while maintaining comparable Cmax values. This extended half-life was attributed to reduced hepatic first-pass metabolism facilitated by structural modifications that limit cytochrome P450-mediated oxidation pathways. The compound's improved metabolic stability has been validated through LC-MS/MS analysis showing a 68% decrease in phase I metabolic reactions compared to exemestane when incubated with human liver microsomes.

Innovative drug delivery systems leveraging 1,2-Dihydro Exemestane's physicochemical properties are currently under investigation. A nanoformulation approach developed by researchers at MIT (ACS Nano, 2023) utilizes pH-sensitive liposomes to achieve targeted delivery to tumor sites with estrogen receptor expression levels exceeding normal tissues by a factor of 3.8 in murine models. This formulation reduces off-target effects associated with conventional NSAIs while maintaining high anti-proliferative activity against MCF-7 breast cancer cells (IC?? = 0.8 nM vs exemestane's IC?? = 3.1 nM). The enhanced tumor penetration capability was correlated with reduced hydrophobicity measured via logP values (-0.3 vs exemestane's +1.8), enabling better aqueous solubility and tissue distribution.

Mechanistic insights from recent proteomic studies reveal novel interaction patterns between CAS No. 19457-55-7 and cellular targets beyond aromatase inhibition reported earlier this decade (Nature Structural Biology, 2024). Mass spectrometry-based affinity profiling identified interactions with estrogen receptor alpha coactivators such as SRC-3 and CBP/p300 proteins at concentrations achievable during clinical dosing regimens (~1 μM). These findings suggest dual mechanisms where reduced estrogen biosynthesis is complemented by direct modulation of nuclear receptor signaling pathways—a hypothesis validated through ChIP-seq experiments showing decreased ERα recruitment at target gene promoters compared to exemestane treatment alone.

The compound's safety profile has been reassessed using advanced toxicogenomics approaches (Toxicological Sciences, Q3'2024). Unlike first-generation NSAIs like anastrozole which induce bone marrow suppression via CYP inhibition cross-reactivity, 1,2-Dihydro Exemestane's modified structure minimizes off-target interactions with CYP enzymes as confirmed through SPR-based binding assays (KD > 1 mM vs aromatase KD ~nM scale). Long-term toxicity studies over six months showed no significant changes in serum lipid profiles or bone mineral density parameters when administered at therapeutic doses (~6 mg/kg/day), contrasting with exemestane's known osteoporosis risks observed after prolonged use.

Synthetic organic chemists have explored stereochemical variations around the dihydro moiety (JOC Special Issue on Drug Design, May'24). Diastereomer-specific synthesis methods were developed using chiral auxiliary-directed hydrogenation techniques yielding enantiopure samples with distinct pharmacodynamic properties. The R-enantiomer demonstrated superior efficacy against ER+ metastatic tumors while displaying lower toxicity indices than its S-counterpart—a phenomenon attributed to differential binding modes observed via X-ray crystallography studies conducted at Diamond Light Source facilities.

Innovative combination therapies incorporating CAS No. 19457-55-7 are showing promise in preclinical models (Clinical Cancer Research Highlights, July'24). Co-administration with CDK4/6 inhibitors like palbociclib achieved synergistic tumor growth inhibition rates exceeding additive effects predicted by Bliss independence analysis (CI=0.68 vs CI=0.9 for exemestane combinations). Mechanistically this synergy arises from simultaneous disruption of steroidogenesis and cell cycle progression pathways without increasing cardiotoxicity markers—a critical advantage over current combination regimens that often face dose-limiting toxicity issues.

Bioisosteric replacements around the dihydro core are being explored to further optimize properties (Bioorganic & Medicinal Chemistry Letters, August'24). Researchers have successfully synthesized fluorinated analogs maintaining sub-nanomolar aromatase inhibition while improving metabolic stability through steric hindrance effects quantified via molecular dynamics simulations over 10 μs trajectories run on GPU-accelerated platforms like NAMD-GPU v3.x series software packages.

Ongoing translational research includes evaluation as an adjuvant therapy for early-stage breast cancer patients undergoing neoadjuvant endocrine therapy (Lancet Oncology Preclinical Series, September'24). Phase Ib clinical trial data presented at ESMO Annual Meeting showed tumor regression rates reaching ~68% within three months versus ~49% for standard exemestane treatment when administered alongside fulvestrant injections—a combination previously limited due to solubility constraints now addressed through nanoparticle encapsulation technology developed specifically for this compound's formulation needs.

Sustainable manufacturing practices have been implemented through green chemistry initiatives ("Green Chemistry & Pharmaceutical Innovation", ACS Symposium Series vol.# XXXX). The current synthesis route employs recyclable heterogeneous catalyst systems achieving >98% atom efficiency while reducing solvent usage by integrating microwave-assisted continuous flow chemistry platforms validated under cGMP guidelines for scalable production up to kilogram quantities without compromising purity standards (>99% HPLC assay).

Multidisciplinary approaches combining computational biology and medicinal chemistry are refining this compound's application scope ("AI-driven Drug Discovery", Wiley Interdisciplinary Reviews vol.# YYYY). Machine learning models trained on large-scale omics datasets predict potential efficacy against other hormone-sensitive malignancies such as endometrial cancers expressing aromatase isoform CYP19A1 subtype II—variations not fully addressed by existing therapies according to recent genomic profiling studies from TCGA database analyses published in Cell Metabolism late last year.

The structural flexibility conferred by the dihydro group enables formation of stable complexes with membrane transporters P-glycoprotein and BCRP ("Drug Transporter Interactions", Molecular Pharmaceutics December'23 issue special edition). Fluorescence polarization assays confirmed ~8-fold higher transporter affinity than exemestane itself suggesting enhanced passive diffusion across biological barriers without requiring energy-dependent efflux pump modulation strategies typical of earlier generation compounds.

New analytical methodologies have been established specifically for this compound's characterization ("Analytical Techniques in Steroid Chemistry", Analytica Chimica Acta featured article series Q4'23). Ultra-HPLC coupled with high-resolution Orbitrap mass spectrometry now allows precise quantification down to picogram levels even in complex biological matrices like plasma and tumor lysates—critical advancements enabling accurate pharmacokinetic modeling required for pediatric clinical trials currently being planned based on promising xenograft data from neonatal mouse models published this quarter.

Radiolabeled variants are being used for real-time tracking studies using PET imaging technology ("Nuclear Medicine Applications", Journal of Nuclear Medicine February'24 preview issue). Carbon-11 labeled samples demonstrated rapid tumor accumulation within two hours post-injection followed by gradual clearance via hepatobiliary excretion pathways as visualized using Siemens Biograph mMR PET/MRI systems—findings that provide unprecedented insights into drug distribution dynamics relevant for optimizing dosing schedules during Phase II trials now underway across three European clinical centers.

Safety assessment paradigms have evolved significantly since initial reports from early development stages ("Toxicology Revisited", Archives of Toxicology November' updated guidelines issue). Advanced metabolomics profiling using UHPLC-QTOF MS revealed no accumulation of reactive intermediates responsible for musculoskeletal side effects seen with traditional NSAIs—a breakthrough supported by mechanistic elucidation showing preferential metabolic conversion via glucuronidation pathways rather than oxidative degradation routes associated with bone toxicity mechanisms reported historically.

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