Oxo Component Research Articles

Oxo-amphiboles in mantle xenoliths: evidence for H2O-rich melt interacting with the lithospheric mantle of Harrow Peaks (Northern Victoria Land, Antarctica)

Amphiboles are the most widespread hydrous metasomatic phases in spinel-bearing mantle peridotites from Harrow Peaks (HP), Northern Victoria Land (Antarctica). They occur both in veinlets and disseminated in the peridotite matrix (preferentially associated with clinopyroxene and spinel grains). Four amphibole crystals were investigated by single-crystal X-ray diffraction (SC-XRD), electron microprobe analysis (EMPA), secondary ion mass spectrometry (SIMS) and micro-Mossbauer spectroscopy; these crystal-chemical data allow to constrain upper mantle conditions during growth of these amphiboles and the role of volatile circulation during metasomatic processes in the Antarctic region. The HP amphiboles have low Mg# values (69.3–84.1), high TiO2 (2.74–5.30 wt%) and FeOtot contents (3.40 to 6.90 wt%). The Fe3+/Fetot ratios are significantly high (0.53–0.66). The W-site is mainly occupied by O2- (0.984–1.187 apfu) plus OH (H2O: 0.70–1.01 wt%) and minor F (0.04–0.24 wt%) and Cl (0.03–0.08 wt%). Consequently, HP amphiboles are actually characterized by a significant oxo component. The aH2O values were calculated at 1.5 GPa by dehydration equilibrium equations written as H2O-buffering equilibria among end-member components of amphibole and coexisting peridotite phases. Three out of four HP amphibole-bearing peridotites have values of aH2O ranging from 0.122 to 0.335; whereas one sample has aH2O remarkably higher (0.782) approaching an ideal H2O basalt solubility. The HP fO2 values, determined by the olivine-spinel-orthopyroxene oxygeobarometer (ΔQFM = −1.77 : +0.01), are remarkably different from those calculated on the basis of the amphibole dehydration equilibrium and the application of the dissociation reaction (ΔQFM = −2.60 : +6.8). The high aH2O and the extremely high fO2 values, determined by the oxy-amphibole equilibrium with respect to the redox conditions recorded by the co-existing anhydrous minerals (close to QFM buffer), revealed that: i) the amphibole-forming reaction is a relatively recent process with the new phases far from having reached a potential equilibrium with the peridotite matrix; ii) amphibole seems to be formed by the precipitation of migrating H2O-rich melts with a negligible contribution of the peridotite system.

Ti-RICH FLUORO-RICHTERITE FROM KARIÅSEN (NORWAY): THE OXO-COMPONENT AND THE USE OF Ti4+AS A PROXY

The crystal-chemical characterization of an amphibole with an unusual composition, A(Na0.76K0.24)B(Ca1.42Na0.56Mn2+0.02)C(Mg2.64Fe2+1.95Mn2+0.07Mg2.64Zn0.01Fe3+0.01Ti4+0.32)T(Si7.18Al0.82)O22W[(OH)0.58O0.27F1.15], found in pegmatitic veins at Kariasen, Larvik Plutonic Complex, Norway, provides an excellent example of the detection and estimation of the oxo component in amphibole. The use of Ti as a proxy for the oxo component is discussed and a procedure to derive accurate Ti partitioning from the results of structure refinement is described. Because the presence and amount of oxo component in amphiboles are important in order to determine values of ƒO2 and ƒH2O, especially in igneous and magmatic systems, this procedure should be applied any time the compositional data or the petrological context indicate the presence of significant Ti, or suggest that the oxo component may be a relevant issue.

Ferri-fluoro-leakeite: a second occurrence at Bratthagen (Norway), with new data on Zn partitioning and the oxo component in Na amphiboles

AbstractA second occurrence of ferri-fluoro-leakeite has been identified in the Bratthagen nepheline syenite pegmatite (Vestfold County, Norway). With respect to the holotype found at the Verkhnee Espe deposit (Akjailyautas Mountains, Kazakhstan; Cámaraet al., 2010), it is closer to the ideal composition because of its larger Li and Mg contents and the absence of an oxo-component; however, it has a significant Zn content (0.29 a.p.f.u.). The ideal formula of ferri-fluoro-leakeite isANaBNa2C(Mg2Fe23+Li)TSi8O22WF2and the empirical formula derived from electron-microprobe analysis and single-crystal structure refinement for the sample used here isA(Na0.68K0.32)S=1.00BNa2.00C(Mg1.69Mn0.252+Fe0.242+Zn0.29Al0.23Fe1.503+Ti0.02Li0.78)S=5.00TSi8O22W(F1.59(OH)0.41)S=2.00. Unitcell data area= 9.788(2),b= 17.826(3),c= 5.282(1) Å, β = 104.195(5)°,V= 893.5 (3) Å3,Z= 2. Crystal-chemical analysis shows that Li is ordered at theM(3) site and Zn is ordered mainly at theM(2) site, confirming previous findings for Li-bearing amphiboles. The new data also make quantification of the oxo component in Na amphiboles possible.

ChemInform Abstract: One‐Pot Synthesis of α‐Acyloxycarboxamidobarbiturates from Alloxans, Carboxylic Acids, and Isocyanides.

AbstractAlloxans are successfully applied as oxo component in the Passerini reaction with carboxylic acids and isonitriles.

Synthetic Applications of Passerini Reaction

Passerini reaction involving an oxo component, an isocyanide, and a nucleophile in a single step to prepare α-acyloxy carboxamide, was first discovered by Passerini about 90 years ago. Various modifications of this reaction have already been developed such as Lewis acids catalysis, in situ oxidation of alcohols to aldehydes, in situ oxidation of aldehydes to carboxylic acids, direct alkylative Passerini reaction, etc. The Passerini reaction has developed in organic synthesis, the total synthesis of natural products, synthesis of polycyclics, macrocycles, heterocycles and pharmaceutical industry for the synthesis of drug-like compounds. The Passerini products could be later cyclized by another type of ring-closing reaction. The aim of this review is to provide an overview of synthetic applications of Passerini reaction. Keywords: Passerini reaction, multicomponent reaction, isocyanide, α-acyloxy carboxamide, heterocycles, multicomponent reactions (MCRs), domino process, α-acyloxy carboxamide moiety, macrocycles, carboxylic acid, N-protected amino acid, aliphatic, aromatic, heteroaromatic carboxylic ester derivatives

UV-initiated self-healing of oxolane–chitosan–polyurethane (OXO–CHI–PUR) networks

These studies show that oxolane–chitosan–polyurethane (OXO–CHI–PUR) networks exhibit self-repairing behavior upon exposure to UV light. Spectroscopic analysis revealed that molecular level processes responsible for the self-repairing mechanism of OXO–CHI–PUR networks are driven by free radical catalyzed polyurea-to-polyurethane conversion, formation of linear –C–O–C– segments via ring opening of OXO rings, as well as chair-to-boat conformational changes of glycosine units of the CHI backbone macromonomer. Incorporation of the OXO five-member ring instead of OXE (four-member) into polyurethane networks facilitates slower but equally effective self-healing characteristics. The role of protic conditions inside the scratch showed that highly acidic environments favor scratch expansions instead of self-healing. Similar to self-healing of OXE–CHI–PUR networks, as a result of mechanical damage, glass transition temperature (Tg) is lowered within the damaged area, resulting in the formation of smaller macromolecular oligomeric entities with enhanced mobility. The repair mechanisms measured by the thermo-mechanical response inside and outside the scratch showed that upon UV light exposure the damaged area is repaired by the frontal growth reactions from the bottom of the scratch to the top, and the mass flow is facilitated by the lower glass transition temperature (Tg) inside the scratch. These studies also show that the presence of hindered amine light stabilizers (HALSs) retards self-healing, which can be compensated by elevated levels of the OXO component in OXO–CHI–PUR networks.

Crystal structure and crystal chemistry of fluoro-potassic-magnesio-arfvedsonite from Monte Metocha, Xixano region, Mozambique, and discussion of the holotype from Quebec, Canada

AbstractFluoro-potassic-magnesio-arfvedsonite, ideally AKBNa2c(Mg4Fe3+)TSi8O22wF2, has been found in a dyke ∼25 km southwest of Monte Metocha, Xixano region, northeastern Mozambique. Fluoro-potassic-magnesio-arfvedsonite and low sanidine form a fine-grained mafic, ultrapotassic, peralkaline igneous rock without visible phenocrysts. The amphibole is brittle, has a Mohs hardness of 6 and a splintery fracture; it is non-fluorescent with perfect {110} cleavage and no observable parting, and has a calculated density of 3.174 gcm−3. In plane-polarized light, it is pleochroic, X= pale grey-green, Y = blue-green, Z = pale grey; X ^ c = 23.6° (in β obtuse), Y ‖ b, Z ^ c = 66.4° (in β acute). Fluoro-potassic-magnesio-arfvedsonite is biaxial negative, α = 1.652(2), β = 1.658(2), γ = 1.660(2); 2Vobs = 22.5(7)°, 2Vcalc = 30.2°. The unit-cell dimensions are a = 9.9591(4), b = 17.9529(7), c = 5.2867(2) Å, β = 104.340(1)°, V = 919.73(10) Å3, Z = 2. The nine strongest X-ray diffraction lines in the experimental powder pattern are: [d in Å(I)(hkl)]: 2.716(100)(151), 3.410(70)(131), 8.475(50)(110), 3.178(50)(310), 3.309(30)(240), 2.762(20)(31), 2.549(20)(260), 2.351(10)(51), 2.269(10)(331). Electron microprobe analysis gave: SiO2 54.25, A12O3 0.03, TiO2 1.08, FeO 6.69, Fe2O3 8.07, MgO 13.99, MnO 0.32, ZnO 0.05, CaO 1.16, Na2O 6.33, K2O 5.20, F 2.20, H2Ocalc 0.74, sum 99.18 wt.%. The formula unit, calculated on the basis of 24 (O,OH,F) with (OH+F) = 2−(2 Ti), is AKa0.98B(Na1.18Ca0.18)∑1.99C(Mg3.07Fe0.832+Mn0.04Al0.01Fe0.903+Ti0.12Zn0.01)∑=4.98TSi8O22W[Fi.o3(OH)0.73O0.24]∑2.00 and confirms the usual pattern of cation order in the amphibole structure. The presence of a significant oxo component (locally balanced by Ti at the M(1) site) is related to the crystallization conditions. The presence of Fe3+ at the T sites, originally suggested for the holotype specimen, is discounted for this amphibole composition.

Novel Approach to 1,5-Benzodiazepine-2-ones Containing Peptoid Backbone via One-Pot Diketene-Based Ugi-4CR

An efficient and simple route for preparation of substituted 1,5-benzodiazepine-2-one containing peptoid backbone is presented. The classical Ugi reaction is considerably extended by application of o-phenylenediamine and diketene as amine and oxo component. 1,3-Dihydro-1,5-benzodiazepine-2-one is generated in situ from these two building blocks combined with isocyanide and aromatic or aliphatic carboxylic acid to assemble the multifunctionalized titled scaffold in high yields. The reaction is performed in the mixture of toluene/CH(2)Cl(2) under reflux condition without catalyst. Conformational isomerism is seen in the solution phase because of restricted free rotation around amide and C-CO bands due to steric bulk of substitutions. In single crystal state, the product is found to possess dimeric structure arising from intermolecular hydrogen bonding.

Solid solution between potassic-obertiite and potassic-fluoro-magnesio-arfvedsonite in a silica-rich lamproite from northeastern Mozambique

A fine-grained dike rock was collected during regional geologic mapping in the Xixano region, northeastern Mozambique. Observation in thin section and SEM and EMP analyses showed a fine-grained igneous texture dominated by optically unusual zoned amphibole and Fe 3+ -bearing low sanidine, with Sr-bearing fluorapatite, rutile, Sr-bearing barite, a silica mineral, hematite and zircon. The mineralogy and major element data indicate an unusual high-silica lamproite. The amphibole is concentrically zoned and pleochroic from pale brown to pale greenish blue, with common abnormal blue and brown interference colours, indicative of high dispersion commonly associated with Fe 3+ . Results of 29 EMP analyses, including two traverses across zoning, were formulated in different modes. The most satisfactory formulae were obtained assuming high Fe 3+ /(Fe 2+ + Fe 3+ ) ratios and significant oxo component (O 2− at the O(3) site substituting for (OH, F)). The most Ti-rich core composition approximates: K Na 2 (Mg 3 Fe 2+ 0.5 Fe 3+ 1 Ti 0.5 ) Si 8 O 22 (F 1 O 1 ), and can be classified as 1:1 solid solution between potassic-obertiite and potassic-fluoro-magnesio-arfvedsonite. Zoning toward the rims increases the potassic-fluoro-magnesio-arfvedsonite component up to K Na 2 (Mg 3.5 Fe 3+ 1.5 ) Si 8 O 22 (F 1 (OH) 0.5 O 0.5 ).

A phase I study of S-1 GI toxicity with and without oxonic acid (Oxo)

13539 Background: S-1 is a fixed combination drug composed of a prodrug of 5-FU (FT), a dihydropyrimidine dehydrogenase (DPD) inhibitor (CDHP), and an inhibitor of 5-FU phosphorylation (Oxo). Due to its GI distribution, the Oxo component of S-1 is expected to protect against 5-FU-evoked GI toxicity without affecting systemic 5-FU exposure. The purpose of this study is to investigate the GI toxicity and dose- limiting toxicities (DLTs) of S-1 (FT+CDHP+Oxo) compared with CFT (FT+CDHP; no Oxo) in a dose escalation design. Methods: Patients with advanced refractory/relapsed solid tumors were randomized to receive either S-1 or CFT administered at 25 mg/m2 bid for 21 days followed by 7 days rest. Dose escalation was planned by 5 mg/m2 increments, with 6 patients maximum per dose level, until 2 DLTs were observed. DLT was defined as G4 hematologic/ ≥G3 non-hematologic treatment-related toxicity in cycle 1. Plasma samples were collected for determination of concentrations of FT, 5-FU, CDHP, Oxo and metabolites. After cycle 1, patients could enroll in an extension phase where all patients received S-1 on the same schedule. Results: A total of 12 patients were enrolled (S- 1=7, CFT=5); 11 (S-1=6, CFT=5) patients were evaluable for DLT. At the 25 mg/m2 dose level, 2 events of G3 diarrhea and 1 sudden death occurred on the CFT arm during cycle 1, while no DLT or drug-related G3/4 events were reported on the S-1 arm. In accordance with the protocol rules, the study was stopped without further dose escalation. S-1 was generally well tolerated in the subsequent extension phase (cycles >1); the most common S-1 related events were fatigue, nausea, and diarrhea. No drug-related G3/4 events were reported for patients in the S-1 arm at any time during study. Single dose PK parameters for FT, 5-FU, CDHP were similar for both S-1 and CFT arms. Conclusions: The Oxo component of S-1 contributes a GI protective effect and a favorable GI safety profile. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Taiho Taiho

A new 5,6-dihydro- 2H-1,3-oxazine synthesis via Asigner-type condensation

In this article - which we dedicate to the lifework 1 of Professor Teruaki Mukaiyama - a new general 5,6-dihydro- 2H-1,3-oxazine synthesis is described. 3-Hydroxy-2,2-dimethylpropionaldehyde is condensed with a second oxo component and ammonia to the title compound in several examples. In the case of citronellal diastereoselectivity is observed.

Chemistry on polymer supports. 1. Polymer-supported wittig reactions

Wittig reactions were studied on a styrene / divinylbenzene (2%) copolymer support having either the oxo component (type-I reaction) or the phosphonium component (type-II reaction) attached via a covalent bond. Model studies yielding 1- p-nitrophenyl-2-polystyrylethylene showed that the product produced by two different routes was the same. Polymer-supported phosphonium salts were prepared in dipolar aprotic solvent, the Wittig reactions were carried out in dimethyl sulfoxide using sodium methylsulfinylmethanide (generated in situ by sodium hydride) as deprotonating agent. The reactions were followed by infrared spectroscopy. High percentages of conversion were achieved with both types of Wittig reaction.