Investigation of the Thionation Reaction of Cyclic Imides

2001 ◽  
Vol 56 (10) ◽  
pp. 1035-1040 ◽  
Author(s):  
A. Orzeszko ◽  
J. K. Maurin ◽  
D. Melon-Ksyta
Keyword(s):  
Oxygen Atom ◽  
Carbonyl Group ◽  
Steric Hindrance ◽  
The Other ◽  
Carbonyl Groups ◽  
Other Hand ◽  
Cyclic Imides ◽  
Lawesson's Reagent ◽  
Main Effects ◽  
High Polarity

A series of monothioimides and dithioimides were synthesised using Lawesson’s reagent. It has been found that two main effects affect thionation reaction. The high polarity of carbonyl groups leads to good yields of mono- and dithioimides. On the other hand, steric hindrance in the vicinity of the carbonyl group strongly inhibits the replacement of the oxygen atom by sulfur.

Synthesis of Novel Benzosuberone Derivatives using Organophosphorus Reagents and their Antitumor Activities

2012 ◽  
Vol 67 (3) ◽  
pp. 243-252 ◽  
Author(s):  
Leila S. Boulos ◽  
Hoda A. Abdel-Malek ◽  
Naglaa F. El-Sayed
Keyword(s):  
Antitumor Activity ◽  
Sodium Hydride ◽  
The Other ◽  
The Novel ◽  
Antitumor Activities ◽  
Lawesson’S Reagent ◽  
Other Hand ◽  
Trialkyl Phosphites ◽  
Lawesson's Reagent ◽  
Sodium Alkoxide

2-Arylidenebenzosuberones react with a Wittig-Horner reagent in the presence of sodium hydride as a base to give the novel dimethyl (4-(4-methoxyphenyl)-2-oxa-2,3,4,5,6,7-hexahydrobenzo- [6,7]cyclohepta[1,2-b]pyran-3-yl)phosphonate. On the other hand, 6,7-dihydrobenzo[6,7]cyclohepta- [1,2-b]pyran-2(5H)-ones were isolated from the reaction of 2-arylidenebenzosuberones withWittig- Horner reagents using alcoholic sodium alkoxide. The reaction of 2-arylidenebenzosuberones with trialkyl phosphites affords the alkyl phosphonate derivatives. Tris(dialkylamino)phosphines react with 2-arylidenebenzosuberones to give the oxaphospholanoxide products. 2-Arylidenebenzosuberones react with Lawesson’s reagent to yield the corresponding dimers. Some of the prepared products were screened for antitumor activity

scholarly journals How COVID-19 Lockdown Impacted on Mobility and Environmental data

2021 ◽  
pp. 3-13
Author(s):  
Claudio Badii ◽  
Pierfrancesco Bellini ◽  
Stefano Bilotta ◽  
Bologna Daniele ◽  
Cenni Claudio ◽  
...  
Keyword(s):  
Smart City ◽  
Imperial College ◽  
Environmental Data ◽  
The Other ◽  
Data Collector ◽  
Global Mobility ◽  
Other Hand ◽  
Main Effects ◽  
The Impact ◽  
Mobility Reduction

According to the COVID-19 lockdown and successive reopening a number of facts can be analysed. The main effects have been detected on: mobility and environment, and specifically on traffic, environmental data and parking. The mobility reduction has been assessed to be quite coherent with respect to what has been described by Google Global mobility report. On the other hand, in this paper a number of additional aspects have been put in evidence providing detailed aspects on mobility and parking that allowed us to better analyse the impact of the reopening on an eventual revamping of the infection, also taking into account of the Rt index. To this end, the collected data from the field have been compared from those of Google and some considerations with respect to the Imperial college Report 20 have been derived. For the pollutant aspects, a relevant reduction on most of them has been measured and rationales are reported. The solution has exploited the Snap4City IOT smart city infrastructure and data collector and Dashboard in place in Tuscany.

Study of Oxidation Behavior of Zn Nanoparticles

2011 ◽  
Vol 399-401 ◽  
pp. 565-568
Author(s):  
Min Wang
Keyword(s):  
Oxygen Atom ◽  
Oxygen Content ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
The Other ◽  
Effective Size ◽  
Other Hand ◽  
Atom Position ◽  
Zn Nanoparticles

Abstract. Zn nanoparticles prepared by the arc was used in the present study. The microsturcture, oxygen content and oxygen atom position in Zn nanoparticles were investigated. Furthermore, the variation of oxygen content with time in the Zn nanoparticles was also studied. The results showed that the effective size of oxidized Zn nanoparticles was about 100nm, and oxidation process was conducted on the surface. On the other hand, the oxygen content in oxidized Zn nanoparticles reduced by comparing with that laying in the air for the same time.

Tricarbonyl(η5-formylcyclopentadienyl)manganese(I) and tricarbonyl(η5-formylcyclopentadienyl)rhenium(I) containing short π(CO)...π(CO) and π(CO)...π interactions

2012 ◽  
Vol 68 (3) ◽  
pp. m69-m72 ◽  
Author(s):  
Alexander S. Romanov ◽  
Gary F. Angles ◽  
Mikhail Yu. Antipin ◽  
Tatiana V. Timofeeva
Keyword(s):  
Hydrogen Bonds ◽  
Carbonyl Group ◽  
Three Dimensional ◽  
The Other ◽  
Carbonyl Groups ◽  
Π Interactions ◽  
Dimensional Network ◽  
Intermolecular Contacts

The structures of tricarbonyl(formylcyclopentadienyl)manganese(I), [Mn(C6H5O)(CO)3], (I), and tricarbonyl(formylcyclopentadienyl)rhenium(I), [Re(C6H5O)(CO)3], (II), were determined at 100 K. Compounds (I) and (II) both possess a carbonyl group in atransposition relative to the substituted C atom of the cyclopentadienyl ring, while the other two carbonyl groups are in almost eclipsed positions relative to their attached C atoms. Analysis of the intermolecular contacts reveals that the molecules in both compounds form stacks due to short attractive π(CO)...π(CO) and π(CO)...π interactions, along the crystallographiccaxis for (I) and along the [201] direction for (II). Symmetry-related stacks are bound to each other by weak intermolecular C—H...O hydrogen bonds, leading to the formation of the three-dimensional network.

Stereocontrolled catalytic hydrogenations of 3-oxocholestanes and some related compounds to the corresponding axial 3-alcohols

1980 ◽  
Vol 58 (11) ◽  
pp. 1061-1068 ◽  
Author(s):  
Masayoshi Ishige ◽  
Michio Shiota
Keyword(s):  
Carbonyl Group ◽  
Cobalt Catalyst ◽  
Solvent Polarity ◽  
The Other ◽  
Nonpolar Solvents ◽  
Ketone Carbonyl Group ◽  
Other Hand ◽  
Ketone Carbonyl ◽  
Related Compounds ◽  
Alcohol Formation

Catalytic hydrogenations of 5α-cholestan-3-ones and related compounds with Urushibara nickel A catalyst in cyclohexane gave a distinct preponderance of unstable axial 3α-ols. Product ratios of axial alcohols decreased with increasing solvent polarity. For 3-oxo-5α-steroids, the cobalt catalyst was less selective for the axial alcohol formation. On the other hand, conversion of 5β-cholestan-3-one into the corresponding axial 3β-ol was most successfully attained by hydrogenation catalyzed by Urushibara cobalt A catalyst in methanol. For such a 5β-ketone, alcoholic media with higher polarities were more favorable for giving the product rich in axial alcohol. The stereochemistry of the products obtained from hydrogenations conducted in nonpolar solvents may be understood in terms of the steric congestion around the ketone carbonyl group. However, when alcohols were used as solvents, the product ratios obtained did not correlate well with the congestion ratios of substrates.

Organic Sulfides and Polysulfides. I. Desulfurization Reactions

1958 ◽  
Vol 31 (3) ◽  
pp. 608-611 ◽  
Author(s):  
Yuji Minoura
Keyword(s):  
Sulfur Content ◽  
Sodium Sulfite ◽  
Potassium Cyanide ◽  
The Other ◽  
Relative Ease ◽  
Diglycolic Acid ◽  
Organic Sulfides ◽  
Other Hand ◽  
Organic Polysulfides ◽  
High Polarity

Abstract Mercury, copper, potassium cyanide and sodium sulfite were found to desulfurize organic polysulfides. In the p,p′-ditolyl and in the dibenzyl series, the di-, tri- and tetrasulfides gave disulfide by desulfurization. On the other hand, in the case of diglycolic acids, di-, tri- and tetrasulfides gave monosulfides. The sulfide, which has high polarity in its radical, is easily desulfurized. The relative ease of desulfurization is—diglycolic acid > dibenzyl > p,p′-tolyl. In the same series, the higher the sulfur content, the more unstable it seems to be. Mercury is more reactive with sulfides than is copper.

BIOGENESE VON ÖSTRIOL-3-MONOGLUCURONID

1967 ◽  
Vol 56 (3) ◽  
pp. 403-412 ◽  
Author(s):  
K. Dahm ◽  
Monika Lindlau ◽  
H. Breuer
Keyword(s):  
Rat Liver ◽  
Steric Hindrance ◽  
Microsomal Fraction ◽  
Enzyme System ◽  
The Other ◽  
Human Intestine ◽  
Enzyme Preparations ◽  
Other Hand ◽  
Enzymatic Reduction

ABSTRACT The biogenesis of oestriol 3-monoglucuronide has been studied using different enzyme preparations of human intestine and placenta as well as of rat liver. After incubation of oestriol with the microsomal fraction of human intestine, oestriol 3-monoglucuronide was found in addition to oestriol 16α-monoglucuronide and oestriol 17β-monoglucuronide. No oestriol 3-monoglucuronide was found when 16α-hydroxyoestrone 3-monoglucuronide, prepared biosynthetically, was incubated with a 24-fold purified human placental 17β-hydroxysteroid:NAD-oxidoreductase. On the other hand, no oestriol 3-monoglucuronide was formed when 17β-oestradiol 3-monoglucuronide was subjected to the action of the microsomal 16α-hydroxylase of rat liver. These results may be explained by steric hindrance of the enzyme system involved. On the basis of the present findings it can be concluded that oestriol 3-monoglucuronide arises exclusively by direct glucuronidation of oestriol, and not by enzymatic reduction of 16α-hydroxyoestrone 3-monoglucuronide or by 16α-hydroxylation of 17β-oestradiol 3-monoglucuronide.

Photo-Oxidation of an IR Vulcanizate

1981 ◽  
Vol 54 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Shoichiro Yano
Keyword(s):  
Ir Spectra ◽  
Rate Constant ◽  
Wavelength Dependence ◽  
The Other ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Absorption Bands ◽  
Photo Oxidation ◽  
Other Hand ◽  
Uv And Ir Spectra

Abstract On irradiation with uv light, changes in uv and ir spectra were observed. In the uv spectrum, a minimum at 290 nm due to sulfur, dibenzothiazyl disulfide, and double bonds in the main chains disappeared initially by the consumption of them; but the minimum reappeared on further irradiation reflecting the formation of carbonyl groups. On the other hand, in the ir spectrum two absorption bands appeared at 1720 cm−1 (due to carbonyl groups) and 3450 cm−1 (due to hydroxyl groups). The latter band faded out suggesting the decomposition of hydroperoxides when the vulcanizate was kept in the dark after irradiation. From the findings of the wavelength dependence of photo-oxidation on uv and ir spectra, it was found that the degradation occurred below about 430 nm. However, investigation of the wavelength dependence of photo-oxidation by the measurement of the crosslink density gave the results that crosslinking reactions occurred below about 340 nm, scissions of C-C and polysulfide crosslinks between 340 and about 400 nm, and scissions of polysulfide crosslinks between 400 and 600 nm. These were confirmed by measurements of the dynamic modulus during irradiation. The relative modulus E′(t)/E′(0) increased on irradiation with light at 253.7 nm in a longer time region reflecting a crosslinking reaction. On the other hand, on irradiation with light above 330 nm, E′(t)/E′(0) decreased with time. Change in E′(t)/E′(0) could be represented by the equation of the first order reaction containing an exponential term and the rate constant was determined. The activation energy was calculated as 18.6 kcal/mole from the temperature dependence of the rate constant and agreed with that for scission of polysulfide crosslinks. The photodegradation of the IR vulcanizate occurred also on irradiation with visible light (> 430 nm), and the modulus decreased.

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 490-497
Author(s):  
Okba Saied ◽  
Benoit Bachand ◽  
James D Wuest
Keyword(s):  
Carbonyl Group ◽  
Carbonyl Compounds ◽  
Lewis Acids ◽  
Carbonyl Oxygen ◽  
The Other ◽  
Keto Group ◽  
Carbonyl Groups ◽  
Lone Pairs ◽  
Related Compounds ◽  
Oxygen Atoms

Carbonyl oxygen atoms have two formal lone pairs of electrons. In principle, both can be used simultaneously to form complexes with two or more Lewis acids. This multiple coordination promises to have a variety of interesting consequences; unfortunately, however, complexes of carbonyl compounds with multiple Lewis acids are extremely rare. To promote multiple coordination, we have made a series of symmetric ketodiesters and related compounds in which the carbonyl group of a ketone is flanked by two additional sites of Lewis basicity. In such compounds, the flanking bases and both lone pairs of the central ketone are available for binding two equivalents of suitable Lewis acids, thereby producing symmetric double chelates in which the central ketone interacts with two Lewis acids at the same time. As expected, treatment of 3-oxoglutarates and 4-oxopimelates with TiCl4 in a 1:1 ratio yielded unsymmetric single chelates in which the carbonyl groups of the ketone and one ester bind TiCl4, while the other ester remains free. Unfortunately, treatment of the same ketodiesters with TiCl4 in a 1:2 ratio did not produce the desired symmetric double chelates. Instead, 2:4 complexes were formed in which the free esters of the unsymmetric single chelates bind TiCl4 in the normal way, without assistance from the keto group. We attribute this observation to the inherent reluctance of ketones to bind multiple Lewis acids, as well as to unfavorable Cl · · ·Cl interactions created in the hypothetical double chelates by the simultaneous attachment of two octahedrally coordinated atoms of titanium to a single carbonyl oxygen atom.Key words: Lewis acids, chelation, ketodiesters, TiCl4.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

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