41 research outputs found
Ficus religiosa L. bark extracts inhibit human rhinovirus and respiratory syncytial virus infection in vitro
Flavonoids and Phenolic Compounds from Litsea polyantha Juss. bark
The 18th International Electronic Conference on Synthetic Organic Chemistry session Bioorganic, Medicinal and Natural Products ChemistryFlavonoids and phenolic compounds from plants have been reported to have multiple biological effects. In the present communication, bioactive compounds from Litsea polyantha Juss. bark were studied. The total phenolic content was determined by using the Folin-Ciocalteu reagent and aluminum chloride colorimetric method was used for determination of total flavonoids. The content of phenolics in 100 gm (dry weight) extract of Litsea polyantha Juss. was 511.472 ± 22.304 mg gallic acid equivalent (GAE), while total flavonoid content was 230.785 ± 5.439 mg/g quercetin equivalent in MELP. Results obtained showed that the plant materials studied are a good source of phenolic and flavonoids compound
Optimization Process for Increasing the Yield of Crude Alkaloid from Litsea polyantha Juss. bark
The 18th International Electronic Conference on Synthetic Organic Chemistry session Bioorganic, Medicinal and Natural Products ChemistryLitsea polyantha Juss. (Lauraceae) also known as Litsea monopetala Roxb. is a small to medium sized evergreen tree distributed chiefly in tropical and subtropical Asia, Australia and the Pacific Islands. The bark of Litsea polyantha Juss. has a long history of medicinal use among the traditional healers of Oraon and Munda community of Jharkhand (India). In this work, optimization process for increasing the yield of crude alkaloid from Litsea polyantha Juss. bark was performed by taking pH and temperature as the factors influencing the yield. With the help of yield optimization by 22 factorial design the percentage yield of crude alkaloid was increased from 3.8% w/w to 17.3% w/
Achieving Surgical, Obstetric, Trauma, and Anesthesia (SOTA) care for all in South Asia
South Asia is a demographically crucial, economically aspiring, and socio-culturally diverse region in the world. The region contributes to a large burden of surgically-treatable disease conditions. A large number of people in South Asia cannot access safe and affordable surgical, obstetric, trauma, and anesthesia (SOTA) care when in need. Yet, attention to the region in Global Surgery and Global Health is limited. Here, we assess the status of SOTA care in South Asia. We summarize the evidence on SOTA care indicators and planning. Region-wide, as well as country-specific challenges are highlighted. We also discuss potential directions—initiatives and innovations—toward addressing these challenges. Local partnerships, sustained research and advocacy efforts, and politics can be aligned with evidence-based policymaking and health planning to achieve equitable SOTA care access in the South Asian region under the South Asian Association for Regional Cooperation (SAARC)
Solvent Effect in Gold(I)-Catalyzed Domino Reaction: Access to Furopyrans
International audienceWe report an efficient synthesis of furopyrans through a gold(I)-catalyzed domino reaction. Starting from the same source, and by changing the solvent of the reaction, two classes of furopyrans are accessible. During this one-step process, which takes place in DMF, two bonds and two heterocycles are formed. DFT calculations furnish the mechanistic understanding of this transformation. The sequence includes a 5-endo-dig cyclization, a regioselective 8-endo-dig cyclization, a retro 8p and a 6p electro-cyclization
Photophysics of a coumarin based Schiff base in solvents of varying polarities
The present work reports detailed photophysics of a coumarin based Schiff base, namely, (E)-7-(((8-hydroxyquinolin-2-yl)methylene)amino)-4-methyl-2H-chromen-2-one (HMC) in different solvents of varying polarity exploiting steady state absorption, fluorescence and time resolved fluorescence spectroscopy. The dominant photophysical features of HMC are discussed in terms of emission from an intramolecular charge transfer (ICT) excited state. Molecular orbital (MO) diagrams as obtained from DFT based computational analysis confirms the occurrence of charge transfer from 8′-hydroxy quinoline moiety of the molecule to the coumarin part. The notable difference in the photophysical response of HMC from its analogous coumarin (C480) lies in a lower magnitude of fluorescence quantum yield of the former, particularly in the solvents of low polarity, which is rationalized by considering the higher rate of non-radiative decay of HMC in apolar solvents. Phosphorescence emission as well as phosphorescence lifetime of HMC has also been reported in 77 K frozen matrix
Developing a corpus of audio-visual attitudinal expressions in Hindi
International audienceThis paper presents a corpus of attitudinal expressions in Hindi and their evaluation by native Hindi speaking raters. The paradigm is adapted from Rilliard et al. (2013), and forms part of an intercultural endeavour aimed at studying prosodic and facial expressions of social affect across languages. Our corpus includes a total of 16 attitudes, such as arrogance, surprise, politeness etc. portrayed by 19 speakers (10f, 9m) of which three experts selected the best four males and females and the better of two turns for subsequent analysis. A followup experiment with more participants employed a total of 512 stimuli, 256 hereof full audiovisual stimuli, 128 audio-only and 128 silent video stimuli. Results indicate higher ratings for emotionally loaded attitudes such as irritation and doubt as compared to, for instance, irony or seductiveness. Reduced modality stimuli were rated more poorly
Gold(I)-Catalyzed Synthesis of Furopyrans: Insight into Hetero-Diels–Alder Reactions
International audienceWe report herein the synthesis of complex molecules containing furopyran cores through a gold(I)-catalyzed hetero Diels-Alder cascade reaction. During this process, the diene and the dienophile are produced concomitantly by the action of a single catalyst from a single starting material. Moreover, six bonds, four heterocycles and four controlled stereogenic centers are formed in a one-step operation. DFT calculations provide the mechanistic basis of this unprecedented reaction. The last 30 years have witnessed an upsurge in the development of methodologies enabling the synthesis of intricate molecular scaffolds from simple precursors. In addition to these new synthetic strategies, the quest for molecular complexity has often resulted in important fundamental insight into selectivity principles. 1 A particularly promising strategy to rapidly construct complex molecules is to trigger domino reactions that convert simple starting materials into highly sophisticated targets by creating several bonds in a one-pot operation. 2 Achieving complexity with brevity is indeed a key to ideal synthesis. The use of transition metal-catalyzed transformations as part of a domino process considerably decreases the energy cost of the overall transformation and favors highly selective reactions due to the pre-organization of the reactive intermediates around the metallic center. In particular, homogeneous gold(I)-catalyzed reactions have attracted much attention because of the great diversity of original and complex molecules that can be obtained from adequately designed substrates, under mild reaction conditions. 3 Recently, few methodologies have been developed using gold(I)-catalysis in domino processes, including hetero Diels-Alder reactions. The hetero Diels-Alder reaction (HDA) is among the most efficient methods for the synthesis of functionalized heterocycles with control of regio-, diastereo-and enantioselectivity. 4 Most of the gold(I)-triggered HDA reported so far rely on the in situ generation of the diene and/or of the dienophile, starting with two different reagents. 5 However, HDA between diene and dienophile obtained from single starting substrate using gold-catalyst remains elusive. We report herein the synthesis of complex polycyclic molecules 4 containing furopyran cores of interest 6 through a gold(I)-catalyzed domino reaction involving HDA (Scheme 1). During this process, both of the dienophile 2 and the diene 3 are produced concomitantly by the action of a single catalyst from a single starting material 1. To our knowledge, this concept has never been exploited. Moreover, during this transformation , six bonds, four heterocycles and four controlled stere-ogenic centers are formed in a one-step operation with 100% atom economy. DFT calculations provide the mechanistic insight of this unprecedented reaction. Scheme 1. Gold(I)-catalyzed hetero Diels-Alder cascade reaction for the synthesis of furopyrans derivatives 4
Developing a corpus of audio-visual attitudinal expressions in Hindi
International audienceThis paper presents a corpus of attitudinal expressions in Hindi and their evaluation by native Hindi speaking raters. The paradigm is adapted from Rilliard et al. (2013), and forms part of an intercultural endeavour aimed at studying prosodic and facial expressions of social affect across languages. Our corpus includes a total of 16 attitudes, such as arrogance, surprise, politeness etc. portrayed by 19 speakers (10f, 9m) of which three experts selected the best four males and females and the better of two turns for subsequent analysis. A followup experiment with more participants employed a total of 512 stimuli, 256 hereof full audiovisual stimuli, 128 audio-only and 128 silent video stimuli. Results indicate higher ratings for emotionally loaded attitudes such as irritation and doubt as compared to, for instance, irony or seductiveness. Reduced modality stimuli were rated more poorly
Leveraging Zn(II) Catalyst: Synthesis of Amidoquinolines via (3 + 3) Heteroannulation of Aromatic Amines and Ynamides
Herein,
we present a ZnÂ(II)-catalyzed (3 + 3) heteroannulation
reaction between aromatic amines and 1,3-diynamides for the synthesis
of amidoquinolines. A large number of aromatic amines are well tolerated,
furnishing quinoline derivatives in up to excellent yield. Notably,
various reactive functional groups have survived under the optimal
reaction conditions, highlighting the mildness of the developed protocol.
In addition, amines derived from bioactive molecules show modest reactivity