scholarly journals Catalyst-Free Synthesis of Polysubstituted 5-Acylamino-1,3-Thiazoles via Hantzsch Cyclization of α-Chloroglycinates

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3846 ◽  
Author(s):  
Mara Tomassetti ◽  
Gabriele Lupidi ◽  
Pamela Piermattei ◽  
Federico V. Rossi ◽  
Samuele Lillini ◽  
...  
Keyword(s):  
Building Blocks ◽  
Heterocyclization Reaction ◽  
Catalyst Free

A catalyst-free heterocyclization reaction of α-chloroglycinates with thiobenzamides or thioureas leading to 2,4-disubstituted-5-acylamino-1,3-thiazoles has been developed. The methodology provides straightforward access to valuable building blocks for pharmaceutically relevant compounds.

scholarly journals A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

2019 ◽  
Vol 15 ◽  
pp. 1523-1533 ◽  
Author(s):  
András György Németh ◽  
György Miklós Keserű ◽  
Péter Ábrányi-Balogh
Keyword(s):  
Elemental Sulfur ◽  
Building Blocks ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalyst Free ◽  
Synthetic Procedure ◽  
Three Component Reaction ◽  
Wide Range ◽  
Organic Chemist ◽  
The One

A new multicomponent reaction has been developed between isocyanides, sulfur and alcohols or thiols under mild reaction conditions to afford O-thiocarbamates and dithiocarbamates in moderate to good yields. The one-pot reaction cascade involves the formation of an isothiocyanate intermediate, thus a catalyst-free synthesis of isothiocyanates, as valuable building blocks from isocyanides and sulfur is proposed, as well. The synthetic procedure suits the demand of a modern organic chemist, as it tolerates a wide range of functional groups, it is atom economic and easily scalable.

Ultrasound irradiation promoted catalyst-free construction of formamidine framework using isocyanide as building blocks

2011 ◽  
Vol 52 (21) ◽  
pp. 2771-2775 ◽  
Author(s):  
Tong-Hao Zhu ◽  
Xu Zhu ◽  
Xiao-Ping Xu ◽  
Tao Chen ◽  
Shun-Jun Ji
Keyword(s):  
Ultrasound Irradiation ◽  
Building Blocks ◽  
Catalyst Free ◽  
Free Construction

ChemInform Abstract: Ultrasound Irradiation Promoted Catalyst-Free Construction of Formamidine Framework Using Isocyanide as Building Blocks.

ChemInform ◽  
2011 ◽  
Vol 42 (34) ◽  
pp. no-no
Author(s):  
Tong-Hao Zhu ◽  
Xu Zhu ◽  
Xiao-Ping Xu ◽  
Tao Chen ◽  
Shun-Jun Ji
Keyword(s):  
Ultrasound Irradiation ◽  
Building Blocks ◽  
Catalyst Free ◽  
Free Construction

O-Vinylphosphonylated Salicylaldehydes as Aldo-Vinyl Bifunctional Building Blocks for anti-3,4-Disubstituted Phosphadihydrocoumarins

Synthesis ◽  
2019 ◽  
Vol 51 (15) ◽  
pp. 2923-2935
Author(s):  
Qinghe Wang ◽  
Dulin Kong ◽  
Tiao Huang ◽  
Mingshu Wu
Keyword(s):  
Building Block ◽  
Building Blocks ◽  
Atom Economy ◽  
Catalyst Free ◽  
Synthetic Strategy

An efficient synthetic strategy for anti-3,4-disubstituted phosphadihydrocoumarin compounds has been established by tandem aza-Michael–aldol-like annulations of tetrahydroisoquinolines with O-vinylphosphonylated salicylaldehydes as an aldo-vinyl bifunctional building block. This conversion was characterized by ‘green’ properties such as a step- and atom-economy, catalyst-free conditions, highly anti-selectivity­, and readily available starting materials.

Catalyst-Free Regioselective Nazarov Cyclization of Aryl Allenyl Ketones

Synthesis ◽  
2017 ◽  
Vol 50 (02) ◽  
pp. 349-360 ◽  
Author(s):  
Maozhong Miao ◽  
Hongjun Ren ◽  
Huaping Xu ◽  
Yi Luo ◽  
Mengchao Jin ◽  
...  
Keyword(s):  
Thermal Condition ◽  
Functional Group ◽  
Building Blocks ◽  
Nazarov Cyclization ◽  
Catalyst Free

The catalyst-free Nazarov cyclization of aryl allenyl ketones under thermal condition is developed. Various densely functionalized 2,3-dihydroindanones or indenones are readily produced in moderate to excellent yields. Significantly, this procedure features high functional group tolerance and exclusive regioselectivity. The resulting substituted 2,3-dihydroindanones can be conveniently converted into valuable conjugated benzofulvene building blocks.

scholarly journals Rapid and catalyst free synthesis of new bis(benzo[g]chromene) and bis(pyrano[3,2-c]chromene) derivatives and optimization of reaction conditions using response surface methodology

RSC Advances ◽  
2019 ◽  
Vol 9 (67) ◽  
pp. 39466-39474
Author(s):  
Fahimeh Sadat Hosseini ◽  
Mohammad Bayat ◽  
Milad Afsharnezhad
Keyword(s):  
Response Surface Methodology ◽  
Optical Properties ◽  
Liquid Crystals ◽  
Response Surface ◽  
Building Blocks ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis

One-pot synthesis of C2-symmetric chromene derivatives, which serve as building blocks to prepare liquid crystals with potential electrical or optical properties.

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

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