Visible-light- and bromide-mediated photoredox Minisci alkylation of N-heterarenes with ester acetates

2021 ◽  
Author(s):  
Chunlian Wang ◽  
Hang Shi ◽  
Guo-Jun Deng ◽  
Huawen Huang
Keyword(s):  
Visible Light ◽  
Ethyl Acetate ◽  
Alkylation Reaction ◽  
Low Toxic ◽  
Alkylation Reagent ◽  
First Time

A visible-light-induced photoredox Minisci alkylation reaction of N-heteroarenes with ethyl acetate has been reported. The low-toxic ethyl acetate was used for the first time as alkylation reagent. Hence, 4-quinazolinones, quinolines...

scholarly journals Identification of Isolated Flavonoid Glycoside From Methanolic Extract of Cucumis dipsaceus Ehrenb. (Fruit)

2018 ◽  
Vol 9 (07) ◽  
Author(s):  
Suman Lata E. ◽  
Sanjiv Kumar Mittal
Keyword(s):  
Visible Light ◽  
Ethyl Acetate ◽  
Methanolic Extract ◽  
2D Nmr ◽  
Flavonoid Glycoside ◽  
Polyphenolic Compounds ◽  
Flavonoid Glycosides ◽  
Tlc Plates ◽  
Rf Values ◽  
First Time

The present study was objected to investigate isolated flavonoid glycoside from methanolic extract from fruits (Cucumis dipsaceus Ehrenb.) as well as identification. Methanolic extract was already screened for the presence of flavonoid glycoside which was strong antioxidant and hepatoprotective agent. It was first time to isolate these by column chromatography with increasing polarity like Petroleum ether, Chloroform, Ethyl acetate and Methanol solvents of different ratios. Each 20ml elute was collected, analyzed with pre coated Merck F254 TLC plates to compare similar spots and Rf values for same category of contents. The similar elutes were pooled, concentrated dried by vacuum distillation with rotary apparatus. The chloroform ethyl acetate fractions (sticky dark brown mass) were analyzed by pre coated F254 TLC plates and then visualized under visible light, UV 254nm and UV366nm. The developed pre coated TLC plates was further derivatized with 0.5% solution of anisaldehyde - H2SO4 acid and again visualized under visible light and UV366nm.TLC, HPTLC and LCMS methods were used to found and estimate polyphenolic compounds. Spectroscopic methods (IR, 1D and 2D NMR and Mass spectrometry) were used to confirm and elucidate the structure. The concluded structure of flavonoid glycosides was quercetin- 3-rutinoside-7-rhamnoside (M Wt: 756.663g/mol) and plaid with literature data

Aryl acyl peroxides for visible-light induced decarboxylative arylation of quinoxalin-2(1H)-ones under additive-, metal catalyst-, and external photosensitizer-free and ambient conditions

2021 ◽  
Author(s):  
Long-Yong Xie ◽  
Sha Peng ◽  
Li-Hua Yang ◽  
Cun Peng ◽  
Ying-Wu Lin ◽  
...  
Keyword(s):  
Visible Light ◽  
Ethyl Acetate ◽  
Metal Catalyst ◽  
Light Illumination ◽  
Ambient Conditions ◽  
Aryl Radicals ◽  
Visible Light Illumination ◽  
First Time

Aryl radicals were generated for the first time from aryl acyl peroxides in ethyl acetate under ambient conditions and visible-light illumination in the absence of any additive, metal catalyst, or external photosensitizer.

scholarly journals An Indoor Visible Light Positioning System Using Tilted LEDs with High Accuracy

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 920
Author(s):  
Neha Chaudhary ◽  
Othman Isam Younus ◽  
Luis Nero Alves ◽  
Zabih Ghassemlooy ◽  
Stanislav Zvanovec ◽  
...  
Keyword(s):  
Visible Light ◽  
Polynomial Regression ◽  
Power Level ◽  
Least Square ◽  
Line Of Sight ◽  
Received Power ◽  
Strength Based ◽  
Complex Linear ◽  
Linear Least Square ◽  
First Time

The accuracy of the received signal strength-based visible light positioning (VLP) system in indoor applications is constrained by the tilt angles of transmitters (Txs) and receivers as well as multipath reflections. In this paper, for the first time, we show that tilting the Tx can be beneficial in VLP systems considering both line of sight (LoS) and non-line of sight transmission paths. With the Txs oriented towards the center of the receiving plane (i.e., the pointing center F), the received power level is maximized due to the LoS components on F. We also show that the proposed scheme offers a significant accuracy improvement of up to ~66% compared with a typical non-tilted Tx VLP at a dedicated location within a room using a low complex linear least square algorithm with polynomial regression. The effect of tilting the Tx on the lighting uniformity is also investigated and results proved that the uniformity achieved complies with the European Standard EN 12464-1. Furthermore, we show that the accuracy of VLP can be further enhanced with a minimum positioning error of 8 mm by changing the height of F.

scholarly journals First thermal studies on visible-light-switchable negative T-type photochromes of a nitrile-rich series

RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 21097-21103
Author(s):  
Mikhail Yu. Belikov ◽  
Mikhail Yu. Ievlev
Keyword(s):  
Thermal Stability ◽  
Visible Light ◽  
Temperature Effect ◽  
Thermal Studies ◽  
First Time ◽  
Thermal Stability Of

The temperature effect on the thermal stability of both the initial and photoinduced forms of nitrile-rich T-type photochromes was studied for the first time.

Synthesis of single-crystalline GeS nanoribbons for high sensitivity visible-light photodetectors

2015 ◽  
Vol 3 (31) ◽  
pp. 8074-8079 ◽  
Author(s):  
Changyong Lan ◽  
Chun Li ◽  
Yi Yin ◽  
Huayang Guo ◽  
Shuai Wang
Keyword(s):  
Visible Light ◽  
Vapor Deposition ◽  
High Performance ◽  
Incident Light ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Single Crystalline ◽  
Promising Application ◽  
Photo Detection ◽  
First Time

Single-crystalline GeS nanoribbons were synthesized by chemical vapor deposition for the first time. The nanoribbon photodetectors respond to the entire visible incident light with a response edge at around 750 nm and a high responsivity, indicating their promising application for high performance broadband visible-light photo-detection.

Visible light-induced C–H sulfenylation using sulfinic acids

2017 ◽  
Vol 19 (20) ◽  
pp. 4785-4791 ◽  
Author(s):  
Pengfei Sun ◽  
Daoshan Yang ◽  
Wei Wei ◽  
Min Jiang ◽  
Zuli Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Sulfur Source ◽  
Sulfinic Acids ◽  
First Time ◽  
Direct Use

The direct use of sulfinic acids as an odorless sulfur source to construct hetroaryl sulfides through a photoredox process has been realized at room temperature for the first time.

scholarly journals A study on Antioxidant Properties of Different Extracts from Kitaibelia balansae

Proceedings ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 23
Author(s):  
Zengin ◽  
Aygun ◽  
Aktumsek
Keyword(s):  
Ethyl Acetate ◽  
Human Body ◽  
Antioxidant Properties ◽  
Water Extract ◽  
Antioxidant Ability ◽  
Chemical Methods ◽  
Potential Source ◽  
First Time ◽  
Antioxidant Effects ◽  
Ethyl Acetate Extracts

Nowadays, knowledge of ancient botanical medicinal practices and application of modern phytochemical techniques have provided the excellent tools for the purification and structural elucidation of various phyto-compounds, which, in turn, has given insights into their mode of action on the human body. This study has been designed to investigate for the first time the antioxidant effects of the ethyl acetate, methanolic, and water extracts of Kitaibelia balansae. Different chemical methods were performed and the observed abilities depend on the solvent used. The best antioxidant ability was noted in water extract, followed by methanol and ethyl acetate extracts. The highest level of phenolic was also detected in water extract. The present findings suggest that K. balansae can be considered as a potential source of bioactive compounds for novel phytopharmaceuticals development

scholarly journals In vitro Antidiabetic, anti-obesity and antioxidant proprities of Rosemary extracts

2014 ◽  
Vol 10 (2) ◽  
pp. 2305-2316 ◽  
Author(s):  
Manel Ben Ali ◽  
Kais Mnafgui ◽  
Abdelfattah Feki ◽  
Mohamed Damak ◽  
Noureddine Allouche
Keyword(s):  
Essential Oil ◽  
Ethyl Acetate ◽  
Pancreatic Lipase ◽  
Antioxidant Properties ◽  
Methanolic Extracts ◽  
Ic50 Values ◽  
Inhibitory Potential ◽  
Prevention Of Diabetes ◽  
First Time

Diabetes mellitus is a serious health problem worldwide that has adverse and long-lasting consequences for individuals, families, and communities. Hence, this study sought to investigate the inhibitory potential of rosemary extracts on key-enzymes related to diabetes such as α-amylase and pancreatic lipase activities, as well as to assess their antioxidant properties in vitro. The IC50 values of Rosemary essential oil, ethyl acetate and methanolic extracts against α-amylase were 28.36, 34.11 and 30.39 µg/mL respectively, and those against pancreatic lipase were 32.25, 36.64 and 34.07 µg/mL, suggesting strong anti-diabetic and anti-obesity effects of Rosemary. The methanolic extract was found to be the highest in levels of phenolic (282.98 µgGAE/mg extract) and flavonoids (161.05 µg QE /mg extract) contents as well as in the antioxidant activity (IC50 = 15.82 µg/mL) as compared to other extracts ethyl acetate (IC50 = 32.23 µg/mL) and essential oil  (IC50 = 96.12 µg/mL).Antioxidant efficacy of Rosemary extracts has been estimated in the stabilization of sunflower oil (SFO) at three different concentrations, i.e. 200 (SFO-200), 500 (SFO-500) and 1000 ppm (SFO-1000). Results showed the highest efficiency of SFO-1000.The results obtained in this study demonstrated for the first time that Rosemary is a potent source of natural inhibitors of α-amylase and pancreatic lipase with powerful antioxidants proprieties that might be used in the food stabilization and the prevention of diabetes and obesity complications as a complementary pharmacological drug.

scholarly journals PHYTOCHEMICAL SCREENING AND BIOLOGICAL EVALUATION OF DYPSIS LEPTOCHEILOS LEAVES EXTRACT AND MOLECULAR DOCKING STUDY OF THE ISOLATED COMPOUNDS

2020 ◽  
pp. 106-113
Author(s):  
HAITHAM ALI IBRAHIM ◽  
FATEHIA SAYED ELSHARAWY ◽  
MAHMMOUD ELHASSAB ◽  
SAMAH SHABANA ◽  
EMAN GABER HAGGAG
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Ethyl Acetate ◽  
Chromatographic Separation ◽  
Ethyl Acetate Fraction ◽  
Docking Study ◽  
Separation Techniques ◽  
Reference Drug ◽  
First Time ◽  
Mcf 7

Objective: phytochemical investigation of the ethyl acetate fraction (EAF) of 80% aqueous methanol extract (AME) of Dypsis leptocheilos leaves, in addition to evaluation of the antioxidant, cytotoxic and antimicrobial activities of the AME and EAF. Docking was used to predict and understand cytotoxicity of the isolated compounds. Methods: The ethyl acetate fraction (EAF) of Dypsis leptocheilos leaves was subjected to different chromatographic separation techniques. Structures of the isolated compounds were established by different spectroscopic techniques (1H/13C NMR). Antioxidant activity was evaluated by DPPH assay, while cytotoxicity was evaluated by MTT cell viability assay. Antimicrobial activity was evaluated by agar diffusion method. The docking study was conducted using Auto Dock Vina; the estrogen receptor (PDB 5t92) was used as a receptor for the docking. Results: Chromatographic separation techniques were led to the isolation of five phenolic compounds; these compounds were identified to be apigenin 8-C-β-D-glucopyranoside (Vitexin) (1), apigenin 6-C-β-D-glucopyranoside (Isovitexin) (2), luteolin 7-O-β-D-glucopyranoside (3), luteolin 8-C-β-D-glucopyranoside (Orientin) (4), luteolin 6-C-β-D-glucopyranoside (Isoorientin) (5). They were isolated and identified for the first time from this plant species. The AME and EAF showed moderate activity against Gram positive and Gram negatvie bacteria, while both of them showed similar and powerful antioxidant activity with SC50 = 12.8±0.56 µg/ml and SC50 = 17±0.77 µg/ml respectively, compared to ascorbic (reference drug) SC50 = 14.2±0.35 µg/ml. The EAF showed higher cytotoxic activity on the MCF-7 cells (human breast cancer cell line), with IC50 = 12.3 ± 1.82 µg/ml, compared to Vinblastine Sulfate (reference drug). All isolated compounds showed good binding affinity to the estrogen receptors existed in the MCF-7 cell. Conclusion: Five phenolic compounds were isolated for the first time from the EAF of Dypsis leptocheilos leaves. The AME and EAF extracts showed variable antioxidant, antimicrobial and cytotoxic activities.

scholarly journals CONTRIBUTE TO STUDY ON CHEMICAL CONSTITUENTS OF URENA LOBATA (L.) OF VIETNAM

2019 ◽  
Vol 57 (2) ◽  
pp. 162
Author(s):  
Quan Minh Pham ◽  
Hoai Van Thi Tran ◽  
Lam Tien Do ◽  
Phuong Lan Doan ◽  
Inh Thi Cam ◽  
...  
Keyword(s):  
Mental Disorders ◽  
Ethyl Acetate ◽  
Ethyl Acetate Extract ◽  
Chemical Constituents ◽  
2D Nmr ◽  
Spectroscopic Methods ◽  
Tree Roots ◽  
Chemical Structures ◽  
Phytochemical Investigation ◽  
First Time

Urena lobata L. is used in Vietnamese traditional medicine for the treatment of several diseases. Tree roots are used to treat rheumatism, dysentery, poor digestion, flu, tonsils, malaria, asthma, goiter. Flowers are used to treat chickenpox, fever, and mental disorders. Branches, leaves or whole trees used to treat injuries bruises, rheumatism, mastitis, bites. Phytochemical investigation of the n-hexan and ethyl acetate extract of Urena lobata L. led to the isolation of β-sitosterol (1), β-sitosterol-3-O-β-D-glucopyranoside (2), a-acetylamino-phenylpropyl a-benzoylamino-phenylpropanoate (3), quercetin (4), and trans-tiliroside (5). Their chemical structures were determined by spectroscopic methods including MS, 1D, 2D NMR and comparing with those reported in previous papers. Two compounds 3, 5 were isolated for the first time from Urena lobata plant.

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