Stereoselective oxirane formation by reaction of diazomethane on 1-fluoro-3-[(4-methylphenyl)sulfinyl]-3-phenylpropan-2-one

1994 ◽  
Vol 72 (8) ◽  
pp. 1769-1779 ◽  
Author(s):  
Pierfrancesco Bravo ◽  
Massimo Frigerio ◽  
Giovanni Fronza ◽  
Vadim Soloshonok ◽  
Fiorenza Viani ◽  
...  
Keyword(s):  
Molecular Modelling ◽  
Chemical Yield ◽  
Main Reaction ◽  
Main Reaction Product ◽  
High Chemical ◽  
Open Chain ◽  
Enol Ethers ◽  
X Ray ◽  
Sulfinyl Group ◽  
By Products

(2S, 2′R,RS)-2-(Fluoromethyl)-2-{[(4-methylphenyl)sulfinyl][phenyl]methyl}oxirane (4) was obtained in high chemical yield and with high diastereoselectivity by reacting diazomethane with pure (3R, RS)-1-fluoro-3-[(4-methylphenyl)sulfinyl]-3-phenylpropan-2-one (3), but also with its (3S, RS)-3-diastereoisomer, in the latter case through inversion of the configuration at carbon 3. The corresponding methyl enol ethers 6 were isolated as by-products. NMR experiments and molecular modelling calculations were performed in order to clarify the equilibria in solution and the preferred conformations of both ketones 3. Several variously substituted, sulfur-free tertiary α-(fluoromethyl)carbinols were obtained from the main reaction product (2S, 2′R,RS)-4 through appropriate elaborations of the sulfinyl group and of the oxirane ring. The structure of (2S, 2′R,RS)-4 was established by X-ray analysis of the open-chain derivative (2S, 2′R,RS)-1-bromo-3-fluoro-2′-{[(4-methylphenyl)sulfinyl][phenyl]methyl}propan-2-ol (7).

Solid-state reaction of Pt thin film with single-crystal (001) β–SiC

1994 ◽  
Vol 9 (3) ◽  
pp. 648-657 ◽  
Author(s):  
J.S. Chen ◽  
E. Kolawa ◽  
M-A. Nicolet ◽  
R.P. Ruiz ◽  
L. Baud ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Single Crystal ◽  
Atomic Scale ◽  
Solid State Reactions ◽  
Main Reaction ◽  
Main Reaction Product ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Interlayer

Thermally induced solid-state reactions between a 70 nm Pt film and a single-crystal (001) β-SiC substrate at temperatures from 300 °C to 1000 °C for various time durations are investigated by 2 MeV He backscattering spectrometry, x-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that Pt reacts with SiC at 500 °C. The product phase identified by x-ray diffraction is Pt3Si. At 600–900 °C, the main reaction product is Pt2Si, but the depth distribution of the Pt atoms changes with annealing temperature. When the sample is annealed at 1000 °C, the surface morphology deteriorates with the formation of some dendrite-like hillocks; both Pt2Si and PtSi are detected by x-ray diffraction. Samples annealed at 500–900 °C have a double-layer structure with a silicide surface layer and a carbon-silicide mixed layer below in contact with the substrate. The SiC—Pt interaction is resolved at an atomic scale with high-resolution electron microscopy. It is found that the grains of the sputtered Pt film first align themselves preferentially along an orientation of {111}Pt//{001}SiC without reaction between Pt and SiC. A thin amorphous interlayer then forms at 400 °C. At 450 °C, a new crystalline phase nucleates discretely at the Pt-interlayer interface and projects into or across the amorphous interlayer toward the SiC, while the undisturbed amorphous interlayer between the newly formed crystallites maintains its thickness. These nuclei grow extensively down into the substrate region at 500 °C, and the rest of the Pt film is converted to Pt3Si. Comparison between the thermal reaction of SiC-Pt and that of Si–Pt is discussed.

scholarly journals Synthesis and crystal structures of two new tin bis(carboranylamidinate) complexes

2017 ◽  
Vol 73 (10) ◽  
pp. 1443-1448 ◽  
Author(s):  
Nicole Harmgarth ◽  
Phil Liebing ◽  
Philipp Hillebrand ◽  
Sabine Busse ◽  
Frank T. Edelmann
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Structure Analysis ◽  
Lone Pair ◽  
Main Reaction ◽  
Similar Reaction ◽  
Main Reaction Product ◽  
X Ray ◽  
Trigonal Bipyramidal Coordination ◽  
Trigonal Bipyramidal

Reaction of 2 equiv. of the lithium carboranylamidinate Li[o-(C2H10B10)C(NCy)(NHCy)] with SnCl2in THF afforded the stannylene compound bis(N,N′-dicyclohexylamidinatocarboranate)tin(II), SnII[o-(C2H10B10)C(NCy)(NHCy)]2(1). A similar reaction of SnCl4with 2 equiv. of Li[o-(C2H10B10)C(NiPr)(NHiPr)] unexpectedly afforded the known solvated pentachloridostannate(IV) salt [Li(THF)4][SnCl5(THF)] as the main reaction product. Small amounts of the new chlorido-tin(IV) bis(carboranylamidinate) bis(N,N′-diisopropylamidinatocarboranate)chloridotin(IV), SnIVCl[o-(C2H10B10)C(NiPr)(NHiPr)][o-(C2H10B10)C(NiPr)2] (2), were isolated as a by-product. Single-crystal X-ray structure analysis revealed aκC,κN-chelating coordination of the carboranylamidinate ligands in both1and2. The Sn atom in1adopts a pseudo-trigonal–bipyramidal coordination under participation of a stereoactive lone pair. In2, a trigonal–bipyramidal coordination of Sn is completed by a chlorido ligand.

scholarly journals X-Ray Molecular and Crystal Structure of Imidazolopyrroloquinoline, a Main Reaction Product of Pyrroloquinolinequinone (PQQ) and L-Tryptophan in Vitro.

1996 ◽  
Vol 44 (7) ◽  
pp. 1387-1390 ◽  
Author(s):  
Toshimasa ISHIDA ◽  
Yasuko IN ◽  
Eiji KAWAMOTO ◽  
Takashi AMANO ◽  
Jyutoku KANAYAMA ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Molecular And Crystal Structure ◽  
Main Reaction ◽  
Main Reaction Product ◽  
X Ray

scholarly journals Incorporation of Waste Glass as an Activator in Class-C Fly Ash/GGBS Based Alkali Activated Material

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3906
Author(s):  
Sasui Sasui ◽  
Gyuyong Kim ◽  
Jeongsoo Nam ◽  
Arie van Riessen ◽  
Hamin Eu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Strength Loss ◽  
Waste Glass ◽  
Main Reaction ◽  
Main Reaction Product ◽  
X Ray ◽  
Granulated Blast Furnace Slag ◽  
Alkali Solutions ◽  
Class C ◽  
Alkali Activated

In this study, an alkaline activator was synthesized by dissolving waste glass powder (WGP) in NaOH-4M solution to explore its effects on the formation of alkali-activated material (AAM) generated by Class-C fly ash (FA) and ground granulated blast furnace slag (GGBS). The compressive strength, flexure strength, porosity and water absorption were measured, and X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) were used to study the crystalline phases, hydration mechanism and microstructure of the resulting composites. Results indicated that the composition of alkali solutions and the ratios of FA/GGBS were significant in enhancing the properties of the obtained AAM. As the amount of dissolved WGP increased in alkaline solution, the silicon concentration increased, causing the accelerated reactivity of FA/GGBS to develop Ca-based hydrate gel as the main reaction product in the system, thereby increasing the strength and lowering the porosity. Further increase in WGP dissolution led to strength loss and increased porosity, which were believed to be due to the excessive water demand of FA/GGBS composites to achieve optimum mixing consistency. Increasing the GGBS proportion in a composite appeared to improve the strength and lower the porosity owing to the reactivity of GGBS being higher than that of FA, which contributed to develop C-S-H-type hydration.

Regioselective Synthesis of Potent 4,5,6,7-Tetrahydroindazole Derivatives via Microwave-assisted Vilsmeier-Haack Reaction and their Antioxidant Activity Evaluation

2019 ◽  
Vol 16 (3) ◽  
pp. 194-201 ◽  
Author(s):  
Renu Bala ◽  
Vandana Devi ◽  
Pratibha Singh ◽  
Navjot Kaur ◽  
Pawandeep Kaur ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Microwave Irradiation ◽  
Biological Activities ◽  
Reaction Times ◽  
Conventional Heating ◽  
High Chemical ◽  
Microwave Assisted ◽  
Work Up ◽  
Active Methylene ◽  
By Products

Background: Tetrahydroindazole, a member of the fused-pyrazole system, is a least studied class of heterocyclic compounds owing to its scarcity in nature. However, a large number of synthetically prepared tetrahydroindazoles are known to show a variety of biological activities such as interleukin- 2 inducible T-Cell kinase inhibitors, AMPA receptor positive allosteric modulators, antitumor, antituberculosis, anti-inflammatory and antimicrobial activities. Vilsmeier-Haack reaction is one of the most important chemical reactions used for formylation of electron rich arenes. Even though Vilsmeier- Haack reaction was studied on a wide variety of hydrazones derived from active methylene compounds, literature lacks the examples of the use of 4-substituted cyclohexanones as a substrate for the synthesis of 4,5,6,7-tetrahydroindazoles. The study of the reaction of Vilsmeier-Haack reagent with hydrazones derived from cyclic keto compounds having active methylene has been considered the interested topic of investigation. In the present study, ethyl cyclohexanone-4-carboxylate was treated with one equivalent of various hydrazines for two hours and the resulted hydrazones were further treated with an OPC-VH reagent (Vilsmeier-Haack reagent isolated from phthaloyl dichloride and N,Ndimethylformamide) afforded 4,5,6,7-tetrahydroindazoles in excellent yields. The synthesized compounds 4a-f and 5a-f were screened for their antioxidant activities using the DPPH radical scavenging assay. The target compounds were synthesized regioselectively using 4+1 approach in excellent yields. A number of experiments using both conventional heating as well as microwave irradiation methods were tried and on comparison, microwave irradiation method was found excellent in terms of easy work up, high chemical yields, shortened reaction times, clean and, no by-products formation. Some of the synthesized compounds showed significant antioxidant activity. The microwave assisted synthesis of 4,5,6,7-tetrahydroindazoles from ethyl cyclohexanone-4-carboxylate has been reported under mild conditions in excellent yield. Easy work up, high chemical yield, shortened reaction times, clean and no by-products formation are the major advantages of this protocol. These advantages may make this method useful for chemists who are interested in developing novel 4,5,6,7-tetrahydroindazole based drugs.

Aiding Factors in the Formation of Azaplatinacyclobutane Rings – X-ray and Crystal Structure of [Pt{CH(Ph)CH2NEt2-κC,κN}(N,N,N′,N′-tetramethylethylenediamine)]+ and of Its Open-Chain Precursor

2007 ◽  
Vol 2007 (15) ◽  
pp. 2144-2150 ◽  
Author(s):  
Giuseppe Lorusso ◽  
Carmen R. Barone ◽  
Nicola G. Di Masi ◽  
Concetta Pacifico ◽  
Luciana Maresca ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Open Chain ◽  
X Ray

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

1991 ◽  
Vol 69 (3) ◽  
pp. 423-431 ◽  
Author(s):  
Yuan L. Chow ◽  
Xinxin Ouyang
Keyword(s):  
Crystallographic Analysis ◽  
Secondary Oxidation ◽  
Enol Ethers ◽  
X Ray ◽  
Thermal Reactions ◽  
Secondary Reactions ◽  
Enol Acetates ◽  
Orthogonal Orientation ◽  
Acid Catalyzed ◽  
Boron Difluoride

The boron difluoride complexes of 2-acetylcyclohexanone, 2-acetylcyclopentanone, and acetylacetone (abbreviated as ACHBF2, ACPBF2, and AABF2) were irradiated in the presence of benzene to give the 1:1 adducts as the primary photoadducts; for certain BF2 complexes, toluene, chlorobenzene, benzonitrile, and methyl benzoate were also used as substrates. The 1,5-diketone photoadducts were assumed to form by a [2+2] photocycloaddition followed by cyclobutane opening and hydrolysis to give 1,2 adducts. They undergo a variety of secondary thermal reactions, probably acid catalyzed, to give enol ethers, enol acetates, acetophenones, and ketonylacetophenones. The efficiency of these secondary reactions determines the final products. Photoaddition with a monosubstituted benzene preferentially occurs at the 3,4 bond without regioselectivity. Under oxygen, ACHBF2 photolytically reacts with benzene to give a secondary oxidation product of a 10-membered cyclic alkylphe-none, which is proven by X-ray crystallographic analysis to have the benzene ring and carbonyl group in orthogonal orientation. It is shown that the singlet excited state ACHBF2 initiates the photoaddition, probably through the formation of the benzene exciplex, which could be detected by its emission. While the Stern–Volmer rates are small, the quantum yield of photoaddition products is as high as 0.12–0.19 under limiting conditions. Key words: [2+2] photocycloaddition, non-planar alkanophenone, macrocyclic alkanophenone, boron difluoride complexes, photoaddition to benzenes.

2D X-ray diffraction and molecular modelling of the crystalline structure of polyesters under uniaxial stress

2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck
Keyword(s):  
Crystalline Structure ◽  
Molecular Modelling ◽  
Three Dimensional ◽  
Uniaxial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Modelling Techniques ◽  
Diffraction Patterns

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.

Synthese des offenkettigen Thioetherthiols ′S8′ -H2 und der Kronenthioether ′S8′ , Bzo2-12 S 4, Bzo4-24 S 8 und Bzo6-36 S 12; Röntgenstrukturanalyse von Bzo4-24 S 8 [1] / Syntheses of the Open-Chain Thioetherthiol ′S8′-H2 and the Crown Thioethers ′S8′, Bzo2-12 S 4, Bzo4-24 S 8 and Bzo6-36 S 12; X-Ray Structure of Bzo4-24 S 8

1991 ◽  
Vol 46 (2) ◽  
pp. 209-215 ◽  
Author(s):  
Dieter Seilmann ◽  
Peter Lechner ◽  
Matthias Moll ◽  
Falk Knoch
Keyword(s):  
Structure Determination ◽  
Open Chain ◽  
X Ray ◽  
Crown Thioethers

The octadendate thioetherthiol ′S8′ - H2 was synthesized by alkylation of the tetradendate thioetherthiol ′S4′ - H2. Further products were the disulfide ′S8′, resulting from the oxidation of ′S8′ - H2, and the crown thioethers Bzo2 -12S4, Bzo4 -24S8 and Bzo6 -36S12. Bzo4 -24S8 was characterized by X-ray structure determination.

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