Aminocoumarins: A Privileged Precursor for the Synthesis of Fused Heterocycles

2019 ◽  
Vol 23 (9) ◽  
pp. 1045-1075 ◽  
Author(s):  
Saigal ◽  
Sumbulunnisan Shareef ◽  
Habibur Rahman ◽  
Md. Musawwer Khan
Keyword(s):  
Chemical Reactivity ◽  
Structural Systems ◽  
Natural Occurrence ◽  
Amino Group ◽  
Active Compounds ◽  
The Past ◽  
Fused Heterocycles

Aminocoumarins are one of the important core structural systems, present in several biologically and medicinally active compounds. Owing to its natural occurrence, potential pharmacological applications and remarkable versatility as a privileged precursor, several proficient synthetic protocols have been reported in the literature over the past years. The presence of an amino group and enamine carbon enhances its chemical reactivity and thus such functionality is repeatedly used for the construction of various fused and simple heterocycles. This review highlights the preparation of different aminocoumarins and their applications for the construction of a variety of five, six and eight membered fused heterocycles.

Potential Use of the Theory of Vulnerability in Information Systems

2012 ◽  
Vol 25 (2) ◽  
pp. 22-33
Author(s):  
Pedro Sá Silva ◽  
Jorge Pinto ◽  
João Varajão ◽  
António Trigo ◽  
Isabel Bentes ◽  
...  
Keyword(s):  
Information Systems ◽  
Structural Systems ◽  
Sensitive Information ◽  
Simulation Studies ◽  
Damage Scenarios ◽  
The Past ◽  
Interesting Approach ◽  
Systems Simulation ◽  
Type Of Failure ◽  
Potential Use

Information Systems in the past few years became a keystone of society. History shows that in some Information Systems one simple failure can lead to disproportioned economic and social damages. Initially used in structural systems, the theory of vulnerability searches for this type of failure. This theory identifies failures in which small damage can have disproportionate impact consequences in terms of the functionality of the whole system. To test and evaluate these failures injections and analyze the impacts of them in sensitive Information Systems, simulation provides an interesting approach. By mimicking systems and representing them through models, simulation studies an imitated system without disrupting the system itself. Simulation provides a safer approach to explore and test the system in damage scenarios without real consequences. This paper discusses the use of the theory of vulnerability in Information Systems simulation.

scholarly journals The antiseptic and trypanocidal action of certain styryl and anil quinoline carboxylamides.*

1932 ◽  
Vol 110 (767) ◽  
pp. 249-260
Keyword(s):  
Amide Group ◽  
The Other ◽  
Amino Group ◽  
Active Compounds ◽  
Basic Group ◽  
Urethane Group ◽  
Highly Active ◽  
Quaternary Compounds ◽  
Quinoline Series

In the case of quaternary compounds of the styryl quinoline series and of the analogous benzthiazole derivatives a powerful trypanocidal effect in vivo has been shown to depend on the presence in the substance of a free basic group in one of the nuclei, and anacylamino (especially acetyl) or urethane group in the other, and also on the styryl linkage—each playing a definite part in contributing to the action (Browning, Cohen, Ellingworth and Gulbransen, 1929, 1931). This is exemplified by 2( p -aminostyryl)-6 acetylamino quinoline methochloride (No. 8), 2( p -dimethylamino styryl)-6 acetylamino quinoline methochloride (No. 25), 2( p -acetylamino)-6 dimethylamino quinoline methochloride (No. 90) and 2( p -dimethylamino styryl) quinolyl (6) urethane (Me) methochloride (No. 125). The effect of acetylation of the amino group parallels that dis­covered by Ehrlich and his co-workers in the case of p -amino phenyl arsinic acid. Gough and King (1930) have recently made the important observation that in the latter series the introduction of an amide group converts the therapeutically inactive carboxylic and sulphonic acids into active compounds. Accordingly, the effect of substituting a carboxylamide group for the acylamino in compounds of the type of No. 25 and its anil analogue (No. 62) has been investigated. In addition, the position of the carboxylamide group has been varied. These substances were further examined for antiseptic action, the results being shown in the table. Trypanocidal properties have been tested on T. brucei infections in mice as in previous work. The striking observation has been made that only those compounds with the carboxylamide group in the 6 position are therapeutically active, the anils being only slightly less effective than the styryl analogues ( cf . Nos. 410, 409 and 385, 403). This contrasts with what is found in the acetylamino derivatives, since the styryl compounds of the latter are highly active as compared with the corresponding anils. The carboxy-ethylamides (420, 419) are more toxic and less trypanocidal than the corresponding amides and methylamides.

Predicted Ductility Demands for Steel Moment Resisting Frames

1989 ◽  
Vol 5 (2) ◽  
pp. 409-427 ◽  
Author(s):  
Charles W. Roeder ◽  
James E. Carpenter ◽  
Hidetake Taniguchi
Keyword(s):  
United States ◽  
Seismic Design ◽  
The United States ◽  
Structural Systems ◽  
Ductility Demand ◽  
Steel Moment Resisting Frames ◽  
The Past ◽  
Moment Resisting Frames ◽  
Column System ◽  
Moment Resisting

Recent changes to the United States seismic design provisions permit the use of weak column-strong beam steel moment resisting frames. This design concept has not been used in the past, because it results in plastic hinges in the columns during moderate or extreme earthquakes. This paper shows the results of inelastic dynamic response calculations on a weak column frame and a comparable strong column system. The results show that the ductility demand is much greater for the weak column strong beam framing system with some acceleration records. The required ductility is then compared for the different structural systems and both are compared to the results of experiments. The comparison suggests that the weak column system may not be able to develop the required ductility. The results of this paper should help define the viability and limits in applicability of the weak column system.

scholarly journals Topological Excitation of Singly Hydrated Hydroxide Complex in Confined Sub-Nanospace for Bright Color Emission and Heterogeneous Catalysis

2020 ◽  
Author(s):  
Xiao-Dan Hu ◽  
Taiqun Yang ◽  
Bingqian Shan ◽  
Bo Peng ◽  
Kun Zhang
Keyword(s):  
Heterogeneous Catalysis ◽  
Chemical Reactivity ◽  
Internal Force ◽  
Physical Origin ◽  
The Past ◽  
Topological Excitation ◽  
History Of ◽  
Bright Color ◽  
Interesting Story ◽  
Color Emission

<p>This excellent story answered two unresolved questions in the past one century and two centuries. The first one is that water is colored or noncolored (<b><i>Water as an Activator of Luminescence. Nature 1930, 125, 706-707</i></b>)? If it is colorful, why and how does it emit the bright colors? The second question is on the physical origin of catalysis or catalyst, i.e., the mysterious internal force of catalysis is what, and how this powerful force determines the chemical reactivity, including activity, selectivity and life times (or stability of catalyst)? (<b><i>A Brief History of Catalysis. CATTECH 2003, 7 (4), 130-138.</i></b>)</p> After reading this interesting story, both seemingly non-related two questions could be perfectly answered by topological excitation of singly hydrated hydroxide complex in confined sub-nanospace.

Preserving the Past as Society Evolves

2019 ◽  
Author(s):  
Robert P. Antes ◽  
Eric R. Ober ◽  
Greggrey G. Cohen
Keyword(s):  
Material Properties ◽  
Urban Environments ◽  
Structural Systems ◽  
The Past ◽  
Investigation Process ◽  
Existing Structure

<p>In urban environments, historic and significant structures are often altered or adapted multiple times for new uses to meet the needs of society. These modifications may occur years apart over the life of the structure, resulting in a combination of different materials and structural systems. Modern-day designers need to fully understand not only the original archaic construction but also the changes imposed during the prior modifications. Drawings for the original building, and subsequent modifications, oftentimes are lacking or incomplete and an investigation is needed to identify the configuration of the existing structure and the various material properties. When considering restoration and strengthening, the information obtained from a well-planned investigation and evaluation can maximize retention of the historic fabric of the structure.</p><p>In this paper/presentation we discuss the importance of performing an investigation prior to modifying the existing structure, the components of an investigation for historic or significant structures, and the challenges that can arise during the investigation process.</p>

scholarly journals The Antioxidant Activity of Prenylflavonoids

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 696 ◽  
Author(s):  
Clementina M. M. Santos ◽  
Artur M. S. Silva
Keyword(s):  
Current Knowledge ◽  
Structural Characteristics ◽  
Side Chain ◽  
Natural Occurrence ◽  
Complex Structures ◽  
Prenylated Flavonoids ◽  
The Past ◽  
Antioxidant Agents ◽  
Synthetic Derivatives ◽  
Review Current

Prenylated flavonoids combine the flavonoid moiety and the lipophilic prenyl side-chain. A great number of derivatives belonging to the class of chalcones, flavones, flavanones, isoflavones and other complex structures possessing different prenylation patterns have been studied in the past two decades for their potential as antioxidant agents. In this review, current knowledge on the natural occurrence and structural characteristics of both natural and synthetic derivatives was compiled. An exhaustive survey on the methods used to evaluate the antioxidant potential of these prenylflavonoids and the main results obtained were also presented and discussed. Whenever possible, structure-activity relationships were explored.

scholarly journals Deceiving suspects about the content of their alibis: consequences for truthful and untruthful suspects

2016 ◽  
Vol 18 (2) ◽  
pp. 143-154 ◽  
Author(s):  
Melanie Sauerland ◽  
Svenja Mehlkopf ◽  
Alana C Krix ◽  
Anna Sagana
Keyword(s):  
Law Enforcement ◽  
Law Enforcement Officers ◽  
Natural Occurrence ◽  
Detection Rates ◽  
Content Type ◽  
Professional Groups ◽  
The Past ◽  
Low Profile ◽  
Interrogation Techniques ◽  
Practical Implications

Purpose – The purpose of this paper is to test how modifying one’s alibi statement interacts with exposure to deceptive interrogation techniques. Design/methodology/approach – In all, 90 participants walked about a university building for 15 minutes and either stole an envelope from a staff pigeonhole (guilty condition) or put the envelope there along the way (innocent condition). Subsequently, participants were asked to provide an alibi for the past 15 minutes. Guilty and half of the innocent participants were instructed to omit that they had been in the vicinity of the pigeonholes. The rest of the innocent participants were asked to tell the truth. Several days later, participants were questioned about six statements taken from their alibis, three of which contained altered information. Findings – As expected, participants were largely blind to our alterations, with detection rates ranging from 1 to 36 percent. Contrary to cognitive load predictions, detection rates did not vary as a function of truthfulness. Rather, guilty participants were less likely to detect alterations than innocents. Research limitations/implications – Memory distrust and guilty suspects’ aim to keep a low profile might be possible explanations for these findings. Practical implications – It is recommended that law enforcement officers and other legal practitioners refrain from using deceptive interrogation techniques and such techniques that can cause inconsistencies in suspects’ reports. Researcher should make it their task to educate these professional groups about the natural occurrence of memory related, non-deceptive inconsistencies in successive statements. Originality/value – This research uses a new methodology to study the effect of deceptive interrogation techniques on both innocent and guilty suspects. The findings are relevant for legal practitioners and researchers.

scholarly journals A convenient synthesis of labelled rhodopsin and studies on its active site

1970 ◽  
Vol 119 (3) ◽  
pp. 359-366 ◽  
Author(s):  
M. D. Hirtenstein ◽  
M. Akhtar
Keyword(s):  
Conformational Change ◽  
Sodium Borohydride ◽  
Active Site ◽  
Cetyltrimethylammonium Bromide ◽  
Chemical Reactivity ◽  
Amino Group ◽  
Polar Environment ◽  
Convenient Synthesis ◽  
First Time ◽  
Native Site

Digitonin solutions of labelled rhodopsin, containing 3H in the retinyl moiety, were prepared by two related methods. Labelled rhodopsin was also prepared for the first time in cetyltrimethylammonium bromide and purified by column chromatography. It was shown that only certain rhodopsin preparations on denaturation in the dark and the reduction with sodium borohydride gave up to 60% of the radioactivity in a fraction characterized as N-retinylphosphatidylethanolamine. Such preparations also gave a lipid-linked retinyl moiety at the metarhodopsin-I stage, but, as expected, a protein-linked retinyl moiety at the metarhodopsin-II stage. Other preparations however, gave exclusively protein-bound radioactivity at the native-rhodopsin, metarhodopsin-I and metarhodopsin-II stages. It is therefore conceivable that the formation of N-retinylphosphatidylethanolamine is due to a non-enzymic reaction resulting from the transfer of the retinyl moiety from its native site to an amino group of a favourably oriented phospholipid molecule. The only firmly established aspect of the rhodopsin active site remains the demonstration in our previous work that at the metarhodopsin-II stage the retinyl moiety is linked to an ∈-amino group of lysine. On the basis of chemical reactivity it is argued that the light-induced conversion of rhodopsin into metarhodopsin II involves a profound conformational change resulting in the dislocation of the retinylideneiminium chromophore from a non-polar environment in rhodopsin to a polar environment in metarhodopsin II.

scholarly journals Highlights on Steroidal Arylidene Derivatives as a Source of Pharmacologically Active Compounds: A Review

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2032
Author(s):  
Vanessa Brito ◽  
Gilberto Alves ◽  
Paulo Almeida ◽  
Samuel Silvestre
Keyword(s):  
Aromatase Inhibitors ◽  
Anticancer Agents ◽  
Chemical Reactivity ◽  
Comprehensive Overview ◽  
Active Compounds ◽  
Structural Modifications ◽  
Pharmacological Interest ◽  
Synthetic Intermediates ◽  
Pharmacologically Active ◽  
Pharmacologically Active Compounds

Steroids constitute a unique class of chemical compounds, playing an important role in physiopathological processes, and have high pharmacological interest. Additionally, steroids have been associated with a relatively low toxicity and high bioavailability. Nowadays, multiple steroidal derivatives are clinically available for the treatment of numerous diseases. Moreover, different structural modifications on their skeleton have been explored, aiming to develop compounds with new and improved pharmacological properties. Thus, steroidal arylidene derivatives emerged as a relevant example of these modifications. This family of compounds has been mainly described as 17β-hydroxysteroid dehydrogenase type 1 and aromatase inhibitors, as well as neuroprotective and anticancer agents. Besides, due to their straightforward preparation and intrinsic chemical reactivity, steroidal arylidene derivatives are important synthetic intermediates for the preparation of other compounds, particularly bearing heterocyclic systems. In fact, starting from arylidenesteroids, it was possible to develop bioactive steroidal pyrazolines, pyrazoles, pyrimidines, pyridines, spiro-pyrrolidines, amongst others. Most of these products have also been studied as anti-inflammatory and anticancer agents, as well as 5α-reductase and aromatase inhibitors. This work aims to provide a comprehensive overview of steroidal arylidene derivatives described in the literature, highlighting their bioactivities and importance as synthetic intermediates for other pharmacologically active compounds.

scholarly journals Seismic design in reinforced concrete

1988 ◽  
Vol 21 (3) ◽  
pp. 208-232
Author(s):  
T. Paulay
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Seismic Design ◽  
Design Methodology ◽  
State Of The Art ◽  
Design Strategy ◽  
Structural Systems ◽  
Capacity Design ◽  
Structural Walls ◽  
The Past

Highlights of the evolution over the past two decades of a seismic design strategy, used in New Zealand for reinforced concrete buildings, are reviewed. After a brief outline of some philosophical concepts of the capacity design methodology, the main features of its application with respect to ductile rigid jointed frames, structural walls and hybrid structural systems are sketched. Another aim of this strategy, complementary to ductility requirements, is to strive for high quality in detailing. Numerous examples are presented to illustrate how this can be achieved. A specific intent of this state of the art review is to report on features of design and detailing which are considered to have originated primarily in New Zealand.

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