Trimethyltin Hydroxide Research Articles

Efficient Fmoc-Protected Amino Ester Hydrolysis Using Green Calcium(II) Iodide as a Protective Agent.

In order to modify amino acids, the C-terminus carboxylic acid usually needs to be protected, typically as a methyl ester. However, standard cleavage of methyl esters requires either highly basic or acidic conditions, which are not compatible with Fmoc or acid-labile protecting groups. This highlights the need for orthogonal conditions that permit selective deprotection of esters to create SPPS-ready amino acids. Herein, mild orthogonal ester hydrolysis conditions are systematically explored using calcium(II) iodide as a protective agent for the Fmoc protecting group and optimized for a broad scope of amino esters. Our optimized reaction improved on the already known trimethyltin hydroxide, as it produced better yields with greener, inexpensive chemicals and a less extensive energy expenditure.

Reframing the Question: Does Mitochondrial Damage Set the Stage for Future Inflammation?

Reframing the Question: Does Mitochondrial Damage Set the Stage for Future Inflammation?

Assessing the Association of Mitochondrial Function and Inflammasome Activation in Murine Macrophages Exposed to Select Mitotoxic Tri-Organotin Compounds.

Background:Mitochondrial function is implicated as a target of environmental toxicants and found in disease or injury models, contributing to acute and chronic inflammation. One mechanism by which mitochondrial damage can propagate inflammation is via activation of the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family, pyrin domain-containing receptor (NLRP)3 inflammasome, a protein complex that processes mature interleukin . plays an important role in the innate immune response and dysregulation is associated with autoinflammatory disorders.Objective:The objective was to evaluate whether mitochondrial toxicants recruit inflammasome activation and processing.Method:Murine macrophages (RAW 264.7) exposed to tri-organotins (triethyltin bromide (TETBr), trimethyltin hydroxide (TMTOH), triphenyltin hydroxide (TPTOH), bis(tributyltin)oxide) [Bis(TBT)Ox] were examined for pro-inflammatory cytokine induction. TMTOH and TETBr were examined in RAW 264.7 and bone marrow-derived macrophages for mitochondrial bioenergetics, reactive oxygen species (ROS) production, and inflammasome activation via visualization of aggregate formation, caspase-1 flow cytometry, enzyme-linked immunosorbent assay and Western blots, and microRNA (miRNA) and mRNA arrays.Results:TETBr and TMTOH induced inflammasome aggregate formation and release in lipopolysaccharide (LPS)-primed macrophages. Mitochondrial bioenergetics and mitochondrial ROS were suppressed. Il1a and Il1b induction with LPS or challenge was diminished. Differential miRNA and mRNA profiles were observed. Lower miR-151-3p targeted cyclic adenosine monophosphate (cAMP)-mediated and AMP-activated protein kinase signaling pathways; higher miR-6909-5p, miR-7044-5p, and miR-7686-5p targeted Wnt beta-catenin signaling, retinoic acid receptor activation, apoptosis, signal transducer and activator of transcription 3, IL-22, IL-12, and IL-10 signaling. Functional enrichment analysis identified apoptosis and cell survival canonical pathways.Conclusion:Select mitotoxic tri-organotins disrupted murine macrophage transcriptional response to LPS, yet triggered inflammasome activation. The differential response pattern suggested unique functional changes in the inflammatory response that may translate to suppressed host defense or prolong inflammation. We posit a framework to examine immune cell effects of environmental mitotoxic compounds for adverse health outcomes. https://doi.org/10.1289/EHP8314

Evaluation of the neuroprotective effects of electromagnetic fields and coenzyme Q10 on hippocampal injury in mouse.

Electromagnetic fields (EMFs) are reported to interfere with chemical reactions involving free radical production. Coenzyme Q10 (CoQ10) is a strong antioxidant with some neuroprotective activities. The purpose of this study was to examine and compare the neuroprotective effects of EMF and CoQ10 in a mouse model of hippocampal injury. Hippocampal injury was induced in mature female mice (25-30 g), using an intraperitoneal injection of trimethyltin hydroxide (TMT; 2.5 mg/kg). The experimental groups were exposed to EMF at a frequency of 50 Hz and intensity of 5.9 mT for 7 hr daily over 1 week or treated with CoQ10 (10 mg/kg) for 2 weeks following TMT injection. A Morris water maze apparatus was used to assess learning and spatial memory. Nissl staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) tests were also performed for the histopathological analysis of the hippocampus. Antiapoptotic genes were studied, using the Western blot technique. The water maze test showed memory improvement following treatment with CoQ10 and coadministration of CoQ10 + EMF. The Nissl staining and TUNEL tests indicated a decline in necrotic and apoptotic cell count following treatment with CoQ10 and coadministration of CoQ10 + EMF. The Western blot study indicated the upregulation of antiapoptotic genes in treatment with CoQ10, as well as coadministration. Also, treatment with EMF had no significant effects on reducing damage induced by TMT in the hippocampus. According to the results, EMF had no significant neuroprotective effects in comparison with CoQ10 on hippocampal injury in mice. Nevertheless, coadministration of EMF and CoQ10 could improve the neuroprotective effects of CoQ10.

Highly Chemoselective Deprotection of the 2,2,2-Trichloroethoxycarbonyl (Troc) Protecting Group.

Nonreducing, pH-neutral conditions for the selective cleavage of the 2,2,2-trichloroethoxycarbonyl (Troc) protecting group are reported. Using trimethyltin hydroxide in 1,2-dichloroethane, Troc-protected alcohols, thiols, and amines can be selectively unmasked in the presence of various functionalities that are incompatible with the reducing conditions traditionally used to remove the Troc group. This mild deprotection protocol tolerates a variety of other hydrolytically sensitive and acid/base-sensitive moieties as well.

Role of Steric Hindrance in the Crystal Packing of Z′ = 4 Superstructure of Trimethyltin Hydroxide

The room-temperature crystal structure of trimethyltin hydroxide, (CH3)3SnOH, has been described by Anderson et al. [Cryst. Growth Des. 2011, 11, 820–826] as a 2a × 2b × 8c, 32-fold superstructure. We report a a × b × 8c, eight-fold superstructure with orthorhombic P21cn symmetry and Z′ = 4. Structured diffuse scattering observed at the positions of presumed superlattice reflections along a* and b* might have appeared as Bragg reflections in the experiment by Anderson et al. Alternatively, Anderson et al. and the present work might have studied different polymorphs of (CH3)3SnOH. Crystalline (CH3)3SnOH constitutes polymeric chains arranged parallel to c. In the eight-fold superstructure at 220 K, the polymeric chains possess a distorted zigzag arrangement of linked linear O–Sn–O units with bent angle at oxygen of ∼139.2°. This structure is essentially different from the 83-helical arrangement in the published 32-fold superstructure model. The origin of the distorted zigzag structure is explained by steric...

Crystal structures of di-aquadi-μ-hydroxido-tris-[tri-methyl-tin(IV)] diformatotri-methyl-stannate(IV) and di-μ-hydroxido-tris-[tri-methyl-tin(IV)] chloride monohydrate.

The title compounds, [Sn3(CH3)9(OH)2(H2O)2][Sn(CH3)3(CHO2)2] (1) and [Sn3(CH3)9(OH)2]Cl·H2O (2), are partially condensed products of hydrolysed tri-methyl-tin chloride. In the structures of 1 and 2, short cationic tris-tannatoxanes (C9H29O2Sn3) are bridged by a diformatotri-methyl-tin anion or a chloride anion, respectively. Hydrogen bridges are present and supposedly stabilize these structures against further polymerization to the known polymeric tri-methyl-tin hydroxide. Especially noteworthy is that the formate present in this structure was formed from atmospheric CO2.

Superspace description of trimethyltin hydroxide at T = 100 K

Abstract At low temperatures the metalorganic compound trimethyltin hydroxide, (CH3)3SnOH, possesses a commensurately modulated crystal structure, the modulation wave vector can be described as q = 1 2 c ∗ . ${\bf{q}}\; = \;{1 \over 2}{{\bf{c}}^ * }.$ The crystal structure is studied by analysing single-crystal X-ray diffraction data within the (3+1)-dimensional superspace approach and superspace group P21212(00γ)00s. The corresponding twofold superstructure has space group symmetry P212121. The structure is characterised by polymeric chains running along c-axis, generated by Sn–O–Sn bridges between neighbouring Sn atoms and packed in a distorted hexagonal pattern and linked via C–H···O interstrand hydrogen bonds along the (orthorhombic) directions [110] and [11̅0], but not along [100].

Synthesis of 5′-carboxymethylsulfonyl-5′-deoxyribonucleosides under mild hydrolytic conditions: a new class of acidic nucleosides as inhibitors of ribonuclease A

Trimethyltin hydroxide mediated synthesis of a new class of RNase A inhibitors. The cytidine analogue emerged as the most efficient inhibitor with a Ki value of 22 ± 2 μM.

The commensurately modulated structure of trimethyltin hydroxide at 220 K

The commensurately modulated structure of trimethyltin hydroxide at 220 K

Synthesis of Stannyl-Substituted Zn4O4 Cubanes as Single-Source Precursors for Amorphous Tin-Doped ZnO and Zn2SnO4 Nanocrystals and Their Potential for Thin Film Field Effect Transistor Applications

The first heterobimetallic alkyl(trimethylstannoxy)zinc clusters with the formula [Me3SnOZnR]4 (R = Me 1, Et 2) are facile accessible by the Bronsted acid−base reaction of trimethyltin hydroxide with the respective zinc dialkyls ZnR2 (R = Me, Et). The resulting products 1 and 2 can be isolated as white solids in high yields (>95%) and were characterized by multinuclear NMR, elemental analysis, FTIR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction analyses. They proved to serve as unprecedented low-temperature single source precursors (SSPs) for the fabrication of tin-containing ZnO as well as zinc stannate semiconducting materials and could be successfully utilized in field effect transistor (FET) applications. The thermal degradation of 1 and 2 under dry synthetic air, monitored by thermogravimetric analysis (TGA and TGA-IR), indicates high volatility of the trimethylstannyl group, which turned out to be the key parameter to control the tin concentration in the final semiconducting p...

Trimethyltin Hydroxide: A Crystallographic and High Z′ Curiosity

The remarkable room temperature structure of trimethyltin hydroxide comprises a total of 32 crystallographically independent SnMe3OH units arranged in four independent coordination polymer strands. We suggest that a Z′ = 4 value is more appropriate than Z′ = 32, reflecting the polymeric structure of the compound. DSC, single crystal and XRPD studies show that on cooling below ca.160 K the structure undergoes a first order phase change to a symmetric Z′ = 1 structure with just one crystallographically unique SnMe3OH unit. The phase change is reversible, and on warming past 176 K the high Z′ structure is regenerated, in an endothermic transition. The Z′ = 1 and 4 structures are an enantiotropic pair, and trimethyltin hydroxide represents a case where the higher Z′ structure is the most stable form at high temperature with the high Z′ value possibly arising from a consideration of the dynamics of the crystal as a whole.

Coordination polymers containing ferrocene backbone. Synthesis, structure and electrochemistry

The reaction of 1,1'-ferrocenedicarboxylic acid (LH(2)) with bis(triphenyltin) oxide afforded a molecular heterobimetallic compound [(Ph(3)Sn)(2)L]. In the latter the two carboxylate units of [L](2-) are involved in an anisobidentate chelating coordination mode to two triphenyl tin units. The reaction of LH(2) with trimethyltin hydroxide or bis(tri-n-butyltin) oxide afforded 2D-coordination polymers [(Me(3)Sn)(2)L](n) and [(n-Bu(3)Sn)(2)L](n) which are formed as a result of anisobidentate bridging coordination action of the two carboxylate units of [L](2-). Interestingly the 2D-coordination polymers contain 24-membered macrocycles each of which is comprised of four trialkyl tin units. The coordination unsaturation of [(Ph(3)Sn)(2)L] can be utilized to form coordination polymers. Accordingly the reaction of LH(2) with bis(triphenyltin) oxide in the presence of ditopic nitrogen ligands such as 4,4'-bipyridine, 4,4'-trimethylenebipyridine or 4,4'-vinylenebipyridine afforded one-dimensional coordination polymers which contain in their backbone three distinct structural components viz., two triorganotin units, a ferrocenyl unit and a bridging nitrogen ligand unit. The coordination polymers, however, do not retain their structural integrity in solution and fall apart to their monomeric units. Electrochemical studies on these hybrid orgaonotin/ferrocene systems reveal that most of them exhibit a single quasi-reversible oxidation peak.

The type 1 interleukin 1 receptor is not required for the death of murine hippocampal dentate granule cells and microglia activation

Alterations in inflammatory process, neuronal death, and glia response have been observed under manipulation of interleukin-1 (IL-1) and subsequent signaling through the type 1 IL-1 receptor (IL-1R1). To investigate the influence of IL-1R1 activation in the pathophysiology of a chemical-induced injury to the murine hippocampus, we examined the level and pattern of neuronal death and neuroinflammation in male weanling mice exposed to trimethyltin hydroxide (2.0 mg TMT/kg, i.p.). Dentate granule cell death occurred at 6 h post-TMT as detected by active caspase 3 immunostaining and presence of lectin positive microglia. The severity of neuronal death and microglia response increased by 12–24 h with elevations in mRNA levels for TNFα and IL-1α. In IL-1R1 null (IL-1R1−/−) mice, the pattern and severity of neuronal death at 24 or 72 h post-TMT was similar as compared to wildtype (WT) mice. In both groups, mRNA levels for TNFα and MIP-1α were elevated, no significant change was seen in either IL-1α or IL-1β, and the early activation of microglia, including their ability to progress to a phagocytic phenotype, was maintained. Compared to WT mice, IL-1R1−/− mice displayed a limited glial fibrillary acidic protein (GFAP) astrocytic response, as well as a preferential induction in mRNA levels of Fas signaling components. Cumulatively, these results indicate that IL-1R1 activation is not necessary for TMT-induced death of dentate granule neurons or local activation of microglia; however, IL-1R1 signaling is involved in mediating the structural response of astrocytes to injury and may regulate apoptotic mechanisms via Fas signaling components.

Mild, efficient and selective hydrolysis of polymer-supported methyl esters using trimethyltin hydroxide

An efficient and selective procedure for a rapid access to polymer-supported carboxylic acids from their corresponding methyl esters using trimethyltin hydroxide is described. Silyl and benzyl ether, and Rink amide linkers are stable to the reaction conditions.

Crystal structure of trimethyltin hydroxide, (CH3)3SnOH

Crystal structure of trimethyltin hydroxide, (CH₃)₃SnOH

A Mild and Selective Method for the Hydrolysis of Esters with Trimethyltin Hydroxide.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Molecular profiles of mRNA levels in laser capture microdissected murine hippocampal regions differentially responsive to TMT‐induced cell death

Using a chemical-induced model of dentate granule (DG) cell death, cDNA microarray analysis was used to identify gene profiles from the laser-captured microdissected (LCM) hippocampal DG cell region versus the CA pyramidal cell layer (CA) from 21-day-old male CD1 mice injected with trimethyltin hydroxide (TMT; 3.0 mg/kg, i.p.). At 6 h post-TMT, lectin + microglia displaying a reactive morphology were in contact with active caspase 3+ neurons. By 18 h, amoeboid microglia and signs of phagocytosis, and a mild astrocytic response were present in the DG. There was no evidence of IgG extravasation in the hippocampus, or cell death and glial reactivity in the CA. Atlas 1.2K Clontech array detected 115 genes changed in the hippocampus with TMT and included genes associated with immediate-early responses, calcium homeostasis, cellular signaling, cell cycle, immunomodulation and DNA repair. Early responses localized to LCM DG samples consisted of elevations in inflammatory factors such as tumor necrosis factor-alpha and receptors, as well as MIP1alpha, CD14, CD18, and a decrease in factors associated with calcium buffering. By 18 h, in the DG, changes occurred in transcripts associated with apoptosis, cell adhesion, DNA repair, cell proliferation and growth. In the CA, a differential level of elevation was seen in CD86 antigen, zinc finger protein 38 and DNA damage inducible transcript 3. A significant number of genes was decreased at these early time points in both hippocampal regions.

A Mild and Selective Method for the Hydrolysis of Esters with Trimethyltin Hydroxide

A Mild and Selective Method for the Hydrolysis of Esters with Trimethyltin Hydroxide

A Mild and Selective Method for the Hydrolysis of Esters with Trimethyltin Hydroxide

Mild, selektiv und effizient: Eine neue Methode mit Trimethylzinnhydroxid zur Hydrolyse bestimmter Esterfunktionen vermeidet ungewollte Eliminierungen und Epimerisierungen. Beispielsweise wird der Ester 1 unter milden Bedingungen in die Carbonsäure 2 umgewandelt, wobei die stereochemische Integrität annähernd gewahrt wird. 1,2-DCE=1,2-Dichlorethan.