scholarly journals Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

2010 ◽  
Vol 6 ◽  
Author(s):  
Norbert Moszner ◽  
Iris Lamparth ◽  
Jörg Angermann ◽  
Urs Karl Fischer ◽  
Frank Zeuner ◽  
...  
Keyword(s):  
Phosphine Oxide ◽  
Acid Chloride ◽  
Storage Stability ◽  
Second Step ◽  
Polar Solvents ◽  
Dental Adhesives ◽  
H Nmr ◽  
The Third ◽  
The Poor ◽  
C Nmr

Because of the poor solubility of the commercially available bisacylphosphine oxides in dental acidic aqueous primer formulations, bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide (WBAPO) was synthesized starting from 3-(chloromethyl)-2,4,6-trimethylbenzoic acid by the dichlorophosphine route. The substituent was introduced by etherification with 2-(allyloxy)ethanol. In the second step, 3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoic acid was chlorinated. The formed acid chloride showed an unexpected low thermal stability. Its thermal rearrangement at 180 °C resulted in a fast formation of 3-(chloromethyl)-2,4,6-trimethylbenzoic acid 2-(allyloxy)ethyl ester. In the third step, the acid chloride was reacted with phenylphosphine dilithium with the formation of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine, which was oxidized to WBAPO. The structure of WBAPO was confirmed by 1H NMR, 13C NMR, 31P NMR, and IR spectroscopy, as well as elemental analysis. WBAPO, a yellow liquid, possesses improved solubility in polar solvents and shows UV–vis absorption, and a high photoreactivity comparable with the commercially available bisacylphosphine oxides. A sufficient storage stability was found in dental acidic aqueous primer formulations.

scholarly journals Chloro- and BF2bdk-substituted dithienylethene: Synthesis, photophysical properties, and optical switching behavior

2020 ◽  
pp. 174751982095141
Author(s):  
Zhiqiang Lu ◽  
Wenbo Yang ◽  
Yanhui Bai ◽  
Mo Wang ◽  
Zixu Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Optical Switching ◽  
High Resolution Mass Spectrometry ◽  
Photophysical Properties ◽  
Red Light ◽  
Switching Behavior ◽  
Polar Solvents ◽  
H Nmr ◽  
Resolution Mass ◽  
C Nmr

A novel chloro- and BF2bdk-substituted dithienylethene derivative, in which a chlorine atom and a difluoroboron β-diketonate (BF2bdk) group are appended at the termini of the dithienylethene core, is developed. The structure was confirmed by 1H NMR, 13C NMR, and high-resolution mass spectrometry (electrospray ionization). It displayed solvent-dependent photophysical properties, and blue/red light-triggered optical switching behavior in nonpolar or less polar solvents.

scholarly journals New bio-polyol based on white mustard seed oil for rigid PUR-PIR foams

2018 ◽  
Vol 20 (2) ◽  
pp. 24-31 ◽  
Author(s):  
Joanna Paciorek-Sadowska ◽  
Marcin Borowicz ◽  
Bogusław Czupryński ◽  
Ewa Tomaszewska ◽  
Joanna Liszkowska
Keyword(s):  
Acid Number ◽  
Raw Material ◽  
Mustard Oil ◽  
Second Step ◽  
Mustard Seed ◽  
White Mustard ◽  
Step Method ◽  
H Nmr ◽  
Polyurethane Composites ◽  
C Nmr

AbstractA new bio-polyol based on white mustard oil (Synapis alba) and 2,2′-mercaptodiethanol (2,2′-MDE) was obtained. The synthesis was carried out by two-step method. In the first stage, the double bond of the unsaturated fatty acid residues was oxidized, and in the second step the epoxy rings were opened with 2,2’-MDE. The properties of the obtained bio-polyol for application as raw material in polyurethane-polyisocyanurate foams (PUR-PIR) - hydroxyl number, acid number, density, viscosity, pH, water content, FTIR,1H NMR and13C NMR were investigated. Based on the obtained results, foaming formulations containing 0 to 0.6 R of the new bio-polyol were prepared. Significant impact of bio-polyol on apparent density, compressive strength, brittleness, flammability, water absorption and thermal conductivity of polyurethane composites were noted. Modified foam had better functional properties than reference foam e.g. lower brittleness, better thermal insulation properties and better fire resistance.

Synthesis of Zingerone Using NiCl2•6H2O-NaBH4 as a Selective Hydrogenation Reaction Agent

2019 ◽  
Vol 948 ◽  
pp. 127-132
Author(s):  
Murdiah ◽  
Deni Pranowo ◽  
Tri Joko Raharjo
Keyword(s):  
Mild Condition ◽  
Selective Hydrogenation ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Hydrogenation Reaction ◽  
Second Step ◽  
H Nmr ◽  
Ft Ir ◽  
High Yields ◽  
C Nmr

Synthesis of zingerone (4-(4-hydroxy-3-methoxyphenyl)-2-butanone) has been done. The first step was to synthesize the compound (4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-on) through a cross aldol condensation reaction between vanilin:acetone mol ratio of 1:5:5, for 5 hours in high yields (97%). The second step was the selective hydrogenation of (4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-on) with NiCl2•6H2O-NaBH4 catalyst in mild condition. Based on the FT-IR, 13C-NMR and 1H-NMR and GC-MS analyses, the synthesis of zingerone has been successfully synthesized by selective hydrogenation reaction with 80% yield.

Users behaviors: The Heritage of Digital World

2014 ◽  
Vol 13 (7) ◽  
pp. 4675-4682
Author(s):  
Atefeh Danesh Moghadam ◽  
Alireza Alagha
Keyword(s):  
Technology Development ◽  
Second Step ◽  
Information Communication ◽  
The Third ◽  
Digital World ◽  
New Concepts ◽  
Emerging Patterns ◽  
History Of ◽  
Fourth Step ◽  
Communication And Technology

In the advent of information era, not only digital world is going to expand its territories, it is going to penetrate into the traditional notions about the meaning of the words and also valorize new concepts. According to Oxford Dictionary, the word heritage is defined: The history, tradition and qualities that a country or society has had for many years and that are considered an important part of its character. In order to present how emerging patterns, as the consequences of technology development, are going to be considered as the new concept of heritage, we follow four steps. In the first step, we present the convergence of Information, Communication and Technology (ICT) and a concise history of its convergence. In the second step, we argue how convergence has culminated in emerging patterns and also has made changes in digital world. In the third step, the importance of users behaviors and its mining is surveyed. Finally, in the fourth step; we illustrate User Generated Contents (UGC) as the most prominent users behaviors in digital world.

Current trends in the structure of eye injuries

2020 ◽  
Vol 21 (3) ◽  
pp. 106-108
Author(s):  
M. N. Ponomareva ◽  
◽  
S. V. Sakharova ◽  
E. M. Pochinok ◽  
E. V. Fomina ◽  
...  
Keyword(s):  
Medical Records ◽  
Young Patients ◽  
Present Stage ◽  
Eye Injuries ◽  
Third Place ◽  
The Third ◽  
Eye Trauma ◽  
Current Trends ◽  
The Poor ◽  
Leading Position

Aim. To identify current trends in hospital eye trauma based on the materials of the specialized ophthalmology department of a round-the-clock hospital. Materials and methods. The analysis of medical records of patients treated in the round-the-clock specialized ophthalmology department of the state medical establishment OKB No. 2 in the period since January 2017-2019. Results. During the analyzed period, 4948 patients were treated, of which 218 patients (5.6%) were identified for nosologies belonging to the category of eye trauma. Men are most often exposed to eye injuries (84%), in addition, in 62% of cases, these are young patients (18-44 years). The structure of eye trauma is almost unchanged: the leading position is occupied by penetrating wounds of the eyeball and contusions, the third place is occupied by burns, through wounds of the eyeball are rare. Conclusions. Given the poor prognosis of the outcome of a severe eyeball injury, it requires the introduction of modern types of microsurgical intervention using endovitreal surgery at the present stage.

The Kinney Three Paragraphs (and More) for Accounting Ph.D. Students

2019 ◽  
Vol 33 (4) ◽  
pp. 1-14 ◽  
Author(s):  
William R. Kinney
Keyword(s):  
Review Process ◽  
Student Experiences ◽  
Second Step ◽  
Practical Relevance ◽  
The Third ◽  
Validity Assessment ◽  
Essential Components ◽  
Potential Problems ◽  
Empirical Accounting Research

SYNOPSIS This Commentary is intended to help beginning Ph.D. students identify, evaluate, and communicate essential components of proposed empirical accounting research using a three-step process. The first step is a structured top-down approach of writing answers to three related questions—What, Why, How—that emphasize the central role of conceptual thinking in research design, as well as practical relevance. The second step is a predictive validity assessment that anticipates concerns likely to arise in the scholarly review process, and the third is consideration of the likely outcome and potential problems to be encountered if the proposal is implemented as planned. First-hand accounts of Ph.D. student experiences using the three paragraphs and three-step approach are presented, along with an exercise that beginners can use to help themselves identify, analyze, and anticipate problems to improve chances for research success ex ante.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

Synthesis of 2-amino-5,7-dimethyl-4-oxopyrido[3,4-e]-1,3-thiazines

1983 ◽  
Vol 48 (12) ◽  
pp. 3426-3432 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Ondrej Forgáč
Keyword(s):  
Spectral Data ◽  
Chlorine Atom ◽  
Mass Spectra ◽  
High Reactivity ◽  
Secondary Amines ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
New Synthesis ◽  
C Nmr

New synthesis of pyrido[3,4-e]-1,3-thiazines consisting in reaction of 2,6-dimethyl-4-chloronicotinoyl isothiocyanate with primary or secondary amines, or with benzaldehyde phenylhydrazone, is described. High reactivity of the chlorine atom does not allow isolation of the corresponding thioureas, arising as intermediates, except in the case of the benzylamino derivative. Structure of the products was unequivocally confirmed by their spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra). The synthesized derivatives do not undergo the Dimroth rearrangement.

Oxynemorensine, an alkaloid from Senecio nemorensis L., var. subdecurrens GRISEB

1980 ◽  
Vol 45 (2) ◽  
pp. 548-558 ◽  
Author(s):  
Antonín Klásek ◽  
Petr Sedmera ◽  
Jindřich Vokoun ◽  
Anna Boeva ◽  
Svatava Dvoráčková ◽  
...  
Keyword(s):  
Unsaturated Acid ◽  
Mass Spectra ◽  
H Nmr ◽  
C Nmr

From S. nemorensis L., var. subdecurrens GRISEB. there were isolated the previously obtained alkaloids nemorensine (I), retroisosenine (II), bulgarsenine (III) and, in addition, the alkaloid oxynemorensine which was assigned the structure VIII on the basis of the interpretation of the 1H-NMR, 13C-NMR, mass spectra, and on that of the identification of the products of hydrolysis and reduction. Furthermore, the isolation of the cis-nemorensic acid (V) as well as that of the unsaturated acid IV, and the transformation of bulgarsenine (III) to nemorensine (I) were described.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

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