Structure and surface properties of Ni-Al hydrotalcite-like compounds and their catalytic application in highly selective acetalization at room temperature

2021 ◽  
Author(s):  
Shu-Yan Cheng ◽  
Jia-Wei Kou ◽  
Kai Sun
Keyword(s):  
Ethylene Glycol ◽  
Surface Properties ◽  
Room Temperature ◽  
Reaction Conditions ◽  
Catalytic Application ◽  
Nitrate Anions

The Ni-Al hydrotalcite-like compounds (Ni-Al HTLCs) containing nitrate anions were synthesized and applied in the acetalization of p-anisaldehyde with ethylene glycol under mild reaction conditions. The Ni-Al HTLCs showed good...

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

A Facile, Efficient and Selective Deprotection of P - Methoxy Benzyl Ethers Using Zinc (II) Trifluoromethanesulfonate

2019 ◽  
Vol 16 (12) ◽  
pp. 955-958
Author(s):  
Reddymasu Sireesha ◽  
Reddymasu Sreenivasulu ◽  
Choragudi Chandrasekhar ◽  
Mannam Subba Rao
Keyword(s):  
Room Temperature ◽  
Protecting Groups ◽  
Side Reactions ◽  
Reaction Conditions ◽  
Acid Sensitivity ◽  
Time Period ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Last Stage ◽  
Zinc Triflate

: Deprotection is significant and conducted over mild reaction conditions, in order to restrict any more side reactions with sensitive functional groups as well as racemization or epimerization of stereo center because the protective groups are often cleaved at last stage in the synthesis. P - Methoxy benzyl (PMB) ether appears unique due to its easy introduction and removal than the other benzyl ether protecting groups. A facile, efficient and highly selective cleavage of P - methoxy benzyl ethers was reported by using 20 mole% Zinc (II) Trifluoromethanesulfonate at room temperature in acetonitrile solvent over 15-120 min. time period. To study the generality of this methodology, several PMB ethers were prepared from a variety of substrates having different protecting groups and subjected to deprotection of PMB ethers using Zn(OTf)2 in acetonitrile. In this methodology, zinc triflate cleaves only PMB ethers without affecting acid sensitivity, base sensitivity and also chiral epoxide groups.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

Rh(III)-Catalyzed Olefination and Alkylation of Arenes with Maleimides: A Tunable Strategy for C(sp2)–H Functionalization

Synthesis ◽  
2021 ◽  
Author(s):  
Hongji Li ◽  
Wenjie Zhang ◽  
Xueyan Liu ◽  
Zhenfeng Tian
Keyword(s):  
Room Temperature ◽  
Functional Group ◽  
Reaction Conditions ◽  
Bond Functionalization ◽  
Alkylation Process ◽  
Coupling Partner

AbstractWe herein report a new nitrogen-directed Rh(III)-catalyzed C(sp2)–H bond functionalization of N-nitrosoanilines and azoxybenzenes with maleimides as a coupling partner, in which the olefination/alkylation process can be finely controlled at room temperature by variation of the reaction conditions. This method shows excellent functional group tolerance, and presents a mild access to the resulting olefination/alkylation products in moderate to good yields.

Process intensification for enzyme assisted turmeric starch hydrolysis in hydrotropic and supercritical conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yogita P. Labrath ◽  
Prafulla V. Belge ◽  
Uma G. Kulkarni ◽  
Vilas G. Gaikar
Keyword(s):  
Residence Time ◽  
Filtration Rate ◽  
Room Temperature ◽  
Curcuma Longa ◽  
Process Intensification ◽  
Enzyme Treatment ◽  
Starch Hydrolysis ◽  
Reaction Conditions ◽  
Natural Form ◽  
Hydrolysis Of

Abstract The turmeric rhizome (Curcuma longa) contains curcuminoids embedded in the starch matrix. It is thus important to target starch hydrolysis to enhance extraction of curcuminoids. In the case of starch hydrolysis, α-amylase is more efficient when the starch is in a gelatinised form than when it is in its natural form. The present work includes hydrolysis of turmeric starch in its natural and gelatinised forms using α-amylase in hydrotrope solution (HS) and scCO2. The optimum rate of starch hydrolysis was obtained using 200 IU cm−3 of α-amylase, at reaction conditions of 6.5 pH at 328 K when 10% w/w of turmeric powder was stirred at 900 rpm in HSs. The hydrolysis in 15 MPa scCO2 at room temperature required a phase modifier and 40 min of residence time (RT). The enzyme treatment of turmeric powder in HSs increased the filtration rate for curcuminoid extraction (gelatinised and native) compared to untreated turmeric powder.

scholarly journals Synthesis of Network Polymers by Means of Addition Reactions of Multifunctional-Amine and Poly(ethylene glycol) Diglycidyl Ether or Diacrylate Compounds

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2047
Author(s):  
Naofumi Naga ◽  
Mitsusuke Sato ◽  
Kensuke Mori ◽  
Hassan Nageh ◽  
Tamaki Nakano
Keyword(s):  
Ethylene Glycol ◽  
Room Temperature ◽  
Addition Reaction ◽  
Monomer Concentration ◽  
Diglycidyl Ether ◽  
Porous Polymers ◽  
Addition Reactions ◽  
Poly Ethylene Glycol ◽  
Network Polymers ◽  
Poly Ethylene

Addition reactions of multi-functional amine, polyethylene imine (PEI) or diethylenetriamine (DETA), and poly(ethylene glycol) diglycidyl ether (PEGDE) or poly(ethylene glycol) diacrylate (PEGDA), have been investigated to obtain network polymers in H2O, dimethyl sulfoxide (DMSO), and ethanol (EtOH). Ring opening addition reaction of the multi-functional amine and PEGDE in H2O at room temperature or in DMSO at 90 °C using triphenylphosphine as a catalyst yielded gels. Aza-Michael addition reaction of the multi-functional amine and PEGDA in DMSO or EtOH at room temperature also yielded corresponding gels. Compression test of the gels obtained with PEI showed higher Young’s modulus than those with DETA. The reactions of the multi-functional amine and low molecular weight PEGDA in EtOH under the specific conditions yielded porous polymers induced by phase separation during the network formation. The morphology of the porous polymers could be controlled by the reaction conditions, especially monomer concentration and feed ratio of the multi-functional amine to PEGDA of the reaction system. The porous structure was formed by connected spheres or a co-continuous monolithic structure. The porous polymers were unbreakable by compression, and their Young’s modulus increased with the increase in the monomer concentration of the reaction systems. The porous polymers absorbed various solvents derived from high affinity between the polyethylene glycol units in the network structure and the solvents.

Bu4N+-Controlled Addition and Olefination with Ethyl 2-(Trimethylsilyl)acetate via Silicon Activation

Synlett ◽  
2017 ◽  
Vol 28 (18) ◽  
pp. 2401-2406 ◽  
Author(s):  
Donal O’Shea ◽  
Manas Das ◽  
Atul Manvar ◽  
Ian Fox ◽  
Dilwyn Roberts
Keyword(s):  
Room Temperature ◽  
Product Formation ◽  
Unsaturated Ester ◽  
Reaction Conditions ◽  
Diverse Range ◽  
Inorganic Cation ◽  
Tetrabutyl Ammonium ◽  
Aldehydes And Ketones ◽  
Subsequent Elimination ◽  
Hydroxy Esters

Catalytic Bu4NOAc as silicon activator of ethyl 2-(trimethylsilyl)acetate, in THF, was utilized for the synthesis of β-hydroxy esters, whereas employing catalytic Bu4NOTMS gave α,β-unsaturated esters. The established reaction conditions were applicable to a diverse range of aromatic, heteroaromatic, aliphatic aldehydes and ketones. Reactions were achieved at room temperature without taking any of the specialized precautions that are in place for other organometallics. A stepwise olefination pathway via silylated β-hydroxy esters with subsequent elimination to form the α,β-unsaturated ester has been demonstrated. The key to selective product formation lies in use of the weaker acetate activator which suppresses subsequent elimination whereas stronger TMSO– activator (and base) facilitates both addition and elimination steps. The use of tetrabutyl ammonium salts for both acetate and trimethylsilyloxide activators provide enhanced silicon activation when compared to their inorganic cation counterparts.

The effects of osmotic pressure changes on the germination of Dictyostelium discoideum spores

1977 ◽  
Vol 23 (9) ◽  
pp. 1170-1177 ◽  
Author(s):  
David A. Cotter
Keyword(s):  
Ethylene Glycol ◽  
Dictyostelium Discoideum ◽  
Room Temperature ◽  
Thermal Inactivation ◽  
Sucrose Concentration ◽  
Lag Phase ◽  
Activation Process ◽  
Sucrose Solutions ◽  
Spore Population ◽  
Pressure Changes

Polyalcohols such as ethylene glycol and glycerol at 3 M penetrate and activate spores of Dictyostelium discoideum incubated at room temperature. Higher concentrations of ethylene glycol result in lysis upon suspension of spores in dilute phosphate buffer. Erythritol and arabitol at 3 M do not penetrate or activate D. discoideum spores.Air-dried spores or those incubated in 2 M sucrose solutions are not activated with the usual heat treatment of 45 °C for 30 min. The plasmolyzed spores are activated at temperatures above 45 °C when heated in the presence of 2 M sucrose for 30 min. The temperature for maximum activation and the temperature for thermal inactivation of spores are raised 7–10 °C in high sucrose concentrations. Long-term incubation of heat-activated spores in 2 M sucrose solutions does not result in a return to dormancy.Moderate sucrose concentrations near 0.2 M do not block the heat-induced activation process but must be removed from the spore population to prevent a return to dormancy within 6 h. Other polyhydric compounds at 0.25 M concentration also cause spore deactivation within 6 h of room temperature incubation. Oxygen uptake of spores undergoing deactivation in 0.18 M sucrose is inhibited as compared to control levels. Moderate concentrations of sucrose do not block the early events of postactivation lag and the spores accumulate at the end of the lag phase. The longer the spores remain unswollen at the end of the postactivation lag phase, the greater the percentage of spores which return to dormancy. The effects of moderate sucrose concentration (lowered water activity) are not duplicated by the same quantity of Ficoll, indicating that the colligative properties of the sucrose solutions are responsible for deactivation.

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