Diastereoselective multi-component tandem condensation: synthesis of 2-amino-4-(2-furanone)-4H-chromene-3-carbonitriles

2019 ◽  
Vol 17 (39) ◽  
pp. 8853-8857 ◽  
Author(s):  
Vijay Gupta ◽  
Debashish Sahu ◽  
Shailja Jain ◽  
Kumar Vanka ◽  
Ravi P. Singh
Keyword(s):  
Reaction Proceeds ◽  
Michael Condensation ◽  
Three Components

Highly syn-selective unification of three components (salicylaldehyde, malononitrile and butenolides) in the presence of sodium tert-butoxide has been realised. The reaction proceeds via a tandem Knoevenagel/Pinner/vinylogous Michael condensation.

The Jovian ring

1984 ◽  
Vol 75 ◽  
pp. 203-209
Author(s):  
Joseph A. Burns
Keyword(s):  
Equatorial Plane ◽  
Charged Particles ◽  
Dynamical Evolution ◽  
Main Band ◽  
Small Grains ◽  
Three Components

ABSTRACTLying in Jupiter's equatorial plane is a diaphanous ring having little substructure within its three components (main band, faint disk, and halo). Micron-sized grains account for much of the visible ring, but particles of centimeter sizes and larger must also be present to absorb charged particles. Since dynamical evolution times and survival life times are quite short (≲102-3yr) for small grains, the Jovian ring is being continually replenished; probably most of the visible ring is generated by micrometeoroids colliding into unseen parent bodies that reside in the main band.

Observations of the Thermal Decomposition of Brucite

1968 ◽  
Vol 26 ◽  
pp. 446-447
Author(s):  
P. L. Burnett ◽  
W. R. Mitchell ◽  
C. L. Houck
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Oxide ◽  
Basal Plane ◽  
Magnesium Ions ◽  
A Value ◽  
Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

Solar photocatalysis mediated by ZnO for the removal of last traces of Indigo carmine dye pollutant from water

2018 ◽  
Vol 4 (02) ◽  
Author(s):  
Veena Vijayan ◽  
Suguna Yesodharan ◽  
E. P. Yesodharan
Keyword(s):  
Indigo Carmine ◽  
Parent Compound ◽  
Oxygen Demand ◽  
Green Technology ◽  
Solar Photocatalysis ◽  
Reaction Proceeds ◽  
Transient Intermediates ◽  
Significant Chemical ◽  
Hydroxyl Free Radicals ◽  
Purification Of Water

Solar photocatalysis as a potential green technology for the removal of traces of the dye pollutant Indigo carmine (IC) from water is investigated using ZnO as the catalyst. Degradation/decolorization alone does not result in complete decontamination as seen from the significant Chemical Oxygen Demand (COD) of water even after the parent compound has disappeared completely. The degradation proceeds through many intermediates which also get mineralized eventually but slowly. Oxalic acid is identified as a stable slow mineralizing degradation product which itself is formed from other transient intermediates. Effect of various parameters such as catalyst dosage, concentration of the dye, pH, temperature, presence of contaminant salts etc. on the degradation is investigated and quantified. Oxidants such as S2O82- and H2O2 have only moderate influence on the degradation. The degradation follows variable kinetics depending on the concentration of the substrate. The reaction proceeds very slowly in the absence of O2 indicating the importance of reactive oxygen species and hydroxyl free radicals in photocatalysis. H2O2 formed insitu in the system undergoes concurrent decomposition resulting in stabilization in its concentration. The study demonstrates that solar photocatalysis can be used as a viable tool for the purification of water contaminated with traces of IC.

Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

2019 ◽  
Author(s):  
Marharyta V. Laktsevich-Iskryk ◽  
Nastassia A. Varabyeva ◽  
Volha V. Kazlova ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Ring Opening ◽  
Radical Intermediates ◽  
Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds <i>via</i> radical intermediates and tolerates various functional groups.

Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

2019 ◽  
Author(s):  
Marharyta V. Laktsevich-Iskryk ◽  
Nastassia A. Varabyeva ◽  
Volha V. Kazlova ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Ring Opening ◽  
Radical Intermediates ◽  
Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds <i>via</i> radical intermediates and tolerates various functional groups.

Catalytic Enantioselective Benzylation Directly from Aryl Acetic Acids

2018 ◽  
Author(s):  
Patrick Moon ◽  
Zhongyu Wie ◽  
Rylan Lundgren
Keyword(s):  
Functional Group ◽  
Terminal Event ◽  
Radical Intermediates ◽  
Carbon Carbon Bond ◽  
Or Groups ◽  
Reaction Proceeds ◽  
Wide Availability ◽  
Metal Catalyzed ◽  
The Stability ◽  
Acetic Acids

The stability and wide availability of carboxylic acids make them valuable reagents in chemical synthesis. Most transition metal catalyzed processes using carboxylic acid substrates are initiated by a decarboxylation event that generates reactive carbanion or radical intermediates. Developing enantioselective methodologies relying on these principles can be challenging, as highly reactive species tend to react indiscriminately without selectivity. Furthermore, anionic or radical intermediates generated from decarboxylation can be incompatible with protic and electrophilic functionality, or groups that undergo trapping with radicals. We demonstrate that metal-catalyzed enantioselective benzylation reactions of allylic electrophiles can occur directly from aryl acetic acids. The reaction proceeds via a pathway in which decarboxylation is the terminal event, occurring after stereoselective carbon–carbon bond formation. The mechanistic features of the process enable enantioselective benzylation without the generation of a highly basic nucleophile. Thus, the process has broad functional group compatibility that would not be possible employing established protocols.<br>

SINERGI ANTARA TRIPUSAT PENDIDIKAN ISLAM DI KECAMATAN NONGGUNONG KABUPATEN SUMENEP

Edupedia ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 1-11
Author(s):  
Zainol Huda
Keyword(s):  
High School ◽  
Junior High School ◽  
Junior High ◽  
Islamic Education ◽  
Report Cards ◽  
Educational Institutions ◽  
Before And After ◽  
New Students ◽  
The Media ◽  
Three Components

The responsibility of Islamic education cannot be carried out unilaterally. Ki Hajar Dewantara stated that it requires the cooperation of three components which called as tripusat pendidikan education (center of three in education), they are families, educational institutions, and society. Those three components are one unit and complement each other. This is what happened at MTs Zainur Ridla (Islamic Junior High School Zainur Ridla) and MTs. Bustanul Ulum (Islamic Junior High School Bustanul Ulum), both of them are in Nonggunong District, Sumenep Regency. The findings in this research indicate that student’s guardians in MTs Zainur Ridla and MTs Bustanul Ulum Nonggunong have awareness about the responsibility of Islamic education. Second, all teacher councils in those two Islamic Junior High School stated that educating responsibility was on their control with habituation for their students in the form of reciting Shalawat Nariyah, reciting short surahs before the lesson began, praying before and after the lesson, shaking hands with teacher councils when coming and going home. Third, the participation of the society in realizing the responsibility of Islamic education through the media and the tradition of Kompolan. Fourth, the pattern of cooperation between madrasah (school) and student’s guardians in the form of: Home visits, inviting student’s guardians, forming madrasah supporting body, and report cards. While the pattern of cooperation between madrasah and society is their involvement in PHBI (Commemoration Islamic Feast Day) activities, their involvement in camp activities, their involvement in accepting new students, and their involvement in enforcing the discipline and regulations at madrasah.

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