scholarly journals Mild Deprotection of Dithioacetals by TMSCl / NaI Association in CH3CN

2020 ◽  
Author(s):  
Olivier Provot ◽  
Yunxin Yao ◽  
Guangkuan Zhao ◽  
Abdallah Hamze ◽  
Mouad Alami
Keyword(s):  
Good Alternative ◽  
Experimental Conditions ◽  
Metal Free ◽  
Free Process ◽  
High Yields ◽  
First Time ◽  
Carbonyl Function

<p><a>We showed for the first time, the fundamental role<b> </b>of CH<sub>3</sub>CN associated to TMSCl/NaI combination to deprotect S,S-ethylene- and S,S-propylene-ketals into ketones. Indeed, if the TMSCl/NaI association leads to the reduction of dithioketals in CH<sub>2</sub>Cl<sub>2</sub>, we have demonstrated that this association can be used to deprotect a large variety of various dithioketals into ketones in CH<sub>3</sub>CN. Otherwise, under mild experimental conditions, O,O-acetals as well as O,S-oxathianes were cleanly deprotected with high yields. It is also possible to easily regenerate the carbonyl function of various hydrazones and imines using this novel protocol. We believe that this metal-free process is a good alternative to other known methodologies used to deprotect dithioketals into ketones.<b></b></a></p><table></table><br>

scholarly journals Mild Deprotection of Dithioacetals by TMSCl / NaI Association in CH3CN

2020 ◽  
Author(s):  
Olivier Provot ◽  
Yunxin Yao ◽  
Guangkuan Zhao ◽  
Abdallah Hamze ◽  
Mouad Alami
Keyword(s):  
Good Alternative ◽  
Experimental Conditions ◽  
Metal Free ◽  
Free Process ◽  
High Yields ◽  
First Time ◽  
Carbonyl Function

<p><a>We showed for the first time, the fundamental role<b> </b>of CH<sub>3</sub>CN associated to TMSCl/NaI combination to deprotect S,S-ethylene- and S,S-propylene-ketals into ketones. Indeed, if the TMSCl/NaI association leads to the reduction of dithioketals in CH<sub>2</sub>Cl<sub>2</sub>, we have demonstrated that this association can be used to deprotect a large variety of various dithioketals into ketones in CH<sub>3</sub>CN. Otherwise, under mild experimental conditions, O,O-acetals as well as O,S-oxathianes were cleanly deprotected with high yields. It is also possible to easily regenerate the carbonyl function of various hydrazones and imines using this novel protocol. We believe that this metal-free process is a good alternative to other known methodologies used to deprotect dithioketals into ketones.<b></b></a></p><table></table><br>

scholarly journals Formal [8+3]-Annulation between Azaoxyallyl Cations and Tropones

Synthesis ◽  
2019 ◽  
Vol 52 (04) ◽  
pp. 553-564
Author(s):  
Guillaume Force ◽  
Amélie Pérot ◽  
Régis Guillot ◽  
Vincent Gandon ◽  
David Leboeuf
Keyword(s):  
Reaction Conditions ◽  
Metal Free ◽  
Dft Computations ◽  
Free Process ◽  
First Time ◽  
Shed Light

For the first time, azaoxyallyl cations were used as cycloaddition partners with tropone derivatives to access nitrogen-containing [7,6]-fused bicycles in a metal-free process under mild reaction conditions. DFT computations have been used to shed light on the selectivities observed during the course of the reaction.

B(C6F5)3-catalyzed metal-free hydrogenation of naphthylamines

2015 ◽  
Vol 13 (10) ◽  
pp. 2875-2878 ◽  
Author(s):  
Gen Li ◽  
Yongbing Liu ◽  
Haifeng Du
Keyword(s):  
Metal Free ◽  
Mild Conditions ◽  
Catalytic Metal ◽  
High Yields ◽  
First Time

A catalytic metal-free hydrogenation of naphthylamines using B(C6F5)3 was achieved under mild conditions for the first time to furnish tetrahydronaphthylamines in high yields.

scholarly journals Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane

2016 ◽  
Vol 12 ◽  
pp. 2614-2619 ◽  
Author(s):  
Riccardo Porta ◽  
Alessandra Puglisi ◽  
Giacomo Colombo ◽  
Sergio Rossi ◽  
Maurizio Benaglia
Keyword(s):  
Continuous Flow ◽  
Reaction Times ◽  
Nitro Compounds ◽  
Primary Amines ◽  
Flow Conditions ◽  
Metal Free ◽  
Nitro Derivatives ◽  
Aromatic Nitro ◽  
High Yields ◽  
First Time

The metal-free reduction of nitro compounds to amines mediated by trichlorosilane was successfully performed for the first time under continuous-flow conditions. Aromatic as well as aliphatic nitro derivatives were converted to the corresponding primary amines in high yields and very short reaction times with no need for purification. The methodology was also extended to the synthesis of two synthetically relevant intermediates (precursors of baclofen and boscalid).

A Borane-Catalyzed Metal-Free Hydrosilylation of Chromones and Flavones

Synlett ◽  
2017 ◽  
Vol 28 (18) ◽  
pp. 2421-2424 ◽  
Author(s):  
Haifeng Du ◽  
Xiaoyu Ren ◽  
Caifang Han ◽  
Xiangqing Feng
Keyword(s):  
Metal Free ◽  
High Yields ◽  
Asymmetric Transformation ◽  
First Time

A Piers-type hydrosilylation of chromones and flavones has been successfully realized for the first time using 0.1 mol % of borane catalyst generated in situ by hydroboration of pentafluorostyrene with HB(C6F5)2 to afford a variety of chromanones and flavanones in 60–99% yields. An attempt for the asymmetric transformation with chiral diyne and HB(C6F5)2 gave chromanones and flavanones in high yields with up to 32% ee.

Improvement of cytoprotective and antioxidant activity of Rosa canina L. and Salix alba L. by controlled differential sieving process against H2O2-induced oxidative stress in mouse primary splenocytes

2017 ◽  
Vol 87 (3-4) ◽  
pp. 191-200 ◽  
Author(s):  
Nidhal Soualeh ◽  
Aliçia Stiévenard ◽  
Elie Baudelaire ◽  
Rachid Soulimani ◽  
Jaouad Bouayed
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
Good Alternative ◽  
Activity Levels ◽  
Salix Alba ◽  
Rosa Canina ◽  
Free Process ◽  
Plant Powders ◽  
Sieving Process

Abstract. In this study, cytoprotective and antioxidant activities of Rosa canina (RC) and Salix alba (SA), medicinal plants, were studied on mouse primary splenocytes by comparing Controlled Differential Sieving process (CDSp), which is a novel green solvent-free process, versus a conventional technique, employing hydroethanolic extraction (HEE). Thus, preventive antioxidant activity of three plant powders of homogeneous particle sizes, 50–100 µm, 100–180 µm and 180–315 µm, dissolved directly in the cellular buffer, were compared to those of hydroethanolic (HE) extract, at 2 concentrations (250 and 500 µg/mL) in H2O2-treated spleen cells. Overall, compared to HE extract, the superfine powders, i. e., fractions < 180 µm, at the lowest concentration, resulted in greater reactive oxygen species (ROS) elimination, increased glutathione peroxidase (GPx) activity and lower malondialdehyde (MDA) production. Better antioxidant and preventive effects in pre-treated cells were found with the superfine powders for SA (i. e., 50–100 µm and 100–180 µm, both p < 0.001), and with the intermediate powder for RC (i. e., 100–180 µm, p < 0.05) versus HE extract. The activity levels of catalase (CAT) and superoxide dismutase (SOD) in pretreated splenocytes exposed to H2O2, albeit reduced, were near to those in unexposed cells, suggesting that pretreatment with the fine powders has relatively restored the normal levels of antioxidant-related enzymes. These findings supported that CDSp improved the biological activities of plants, avoiding the use of organic solvents and thus it could be a good alternative to conventional extraction techniques.

An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani
Keyword(s):  
Reaction Medium ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Substituted Benzaldehydes ◽  
High Yields ◽  
First Time ◽  
Green Conditions

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

scholarly journals The effect of salinity on enterocytozoon hepatopenaei infection in Penaeus vannamei under experimental conditions

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
L. F. Aranguren Caro ◽  
F. Alghamdi ◽  
K. De Belder ◽  
J. Lin ◽  
H. N. Mai ◽  
...  
Keyword(s):  
Penaeus Monodon ◽  
Oral Route ◽  
Western Hemisphere ◽  
Penaeus Vannamei ◽  
Asian Countries ◽  
Experimental Conditions ◽  
Reliable Source ◽  
Specific Pathogen ◽  
Enterocytozoon Hepatopenaei ◽  
First Time

Abstract Background Enterocytozoon hepatopenaei (EHP) is an enteric pathogen that affects Penaeus vannamei and Penaeus monodon shrimp in many SE Asian countries. In the western hemisphere, EHP was reported for the first time in 2016 in farmed P. vannamei in Venezuela. Anecdotal evidence suggests that EHP is more prevalent in grow-out ponds where the salinity is high (> 15 parts per thousand (ppt)) compared to grow-out ponds with low salinities (< 5 ppt). Considering that P. vannamei is an euryhaline species, we were interested in knowing if EHP can propagate in P. vannamei in low salinities. Results In this study, we described an experimental infection using fecal strings as a source inoculum. Specific Pathogen Free (SPF) P. vannamei were maintained at three different salinities (2 ppt, 15 ppt, and 30 ppt) while continuously challenged using feces from known EHP-infected P. vannamei over a period of 3 weeks. The fecal strings, used as a source of EHP inocula in the challenges, was sufficient to elicit an infection in shrimp maintained at the three salinities. The infectivity of EHP in shrimp reared at 2 ppt, 15 ppt, and 30 ppt salinities was confirmed by PCR and histopathology. The prevalence and the severity of the EHP infection was higher at 30 ppt than at 2 ppt and 15 ppt. Conclusion The data suggests that fecal strings are a reliable source of EHP inoculum to conduct experimental challenges via the fecal-oral route. An EHP infection can occur at a salinity as low as 2 ppt, however, the prevalence and the severity of the EHP infection is higher at a salinity of 30 ppt.

Electrochemical-induced synthesis of quinazolinones via cathode hydration of o-aminobenzonitriles in aqueous solution

2021 ◽  
Author(s):  
Li Yang ◽  
Huiqing Hou ◽  
Lan Li ◽  
Jin Wang ◽  
Sunying Zhou ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Transition Metal ◽  
Metal Free ◽  
Free Process

An efficient and practical electrochemical-catalyzed transition metal-free process for the synthesis of substituted quinazolinones from simple and readily available o-aminobenzonitriles and aldehydes in water has been accomplished. I2/base and water...

scholarly journals Comparative investigation of lasing and amplification performance in cryogenic Yb:YLF systems

2021 ◽  
Vol 127 (3) ◽  
Author(s):  
Umit Demirbas ◽  
Martin Kellert ◽  
Jelto Thesinga ◽  
Yi Hua ◽  
Simon Reuter ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Estimation Method ◽  
Laser Cavity ◽  
Comparative Investigation ◽  
Limiting Factor ◽  
Experimental Conditions ◽  
Temperature Estimation ◽  
Transverse Temperature ◽  
First Time

AbstractWe present detailed experimental results with cryogenic Yb:YLF gain media in rod-geometry. We have comparatively investigated continuous-wave (cw) lasing and regenerative amplification performance under different experimental conditions. In the cw lasing experiments effect of crystal doping, cw laser cavity geometry and pump wavelength on lasing performance were explored. Regenerative amplification behavior was analyzed and the role of depolarization losses on performance was investigated. A recently developed temperature estimation method was also employed for the first time in estimating average crystal temperature under lasing conditions. It is shown that the thermal lens induced by transverse temperature gradients is the main limiting factor and strategies for future improvements are discussed. To the best of our knowledge, the achieved results in this study (375 W in cw, and 90 W in regenerative amplification) are the highest average powers ever obtained from this system via employing the broadband E//a axis.

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