Synthesis of Heterogeneous Ir0∼600–900/γ-Al2O3 in One Pot From the Precatalyst Ir(1,5-COD)Cl/γ-Al2O3: Discovery of Two Competing Trace “Ethyl Acetate Effects” on the Nucleation Step and Resultant Product

ACS Catalysis ◽  
2016 ◽  
Vol 6 (8) ◽  
pp. 5449-5461 ◽  
Author(s):  
Patrick Kent ◽  
Joseph E. Mondloch ◽  
Richard G. Finke
Keyword(s):  
2004 ◽  
Vol 77 (5) ◽  
pp. 1027-1028 ◽  
Author(s):  
Valeriy A. Bacherikov ◽  
May-Jane Wang ◽  
Shu-Yun Cheng ◽  
Ching-Huang Chen ◽  
Kuo-Tung Chen ◽  
...  
Keyword(s):  

Author(s):  
Serap Sahin ◽  
Johan Wärnå ◽  
Päivi Mäki-Arvela ◽  
Tapio Salmi ◽  
Dmitry Yu. Murzin

1992 ◽  
Vol 45 (1) ◽  
pp. 205 ◽  
Author(s):  
R Noyori ◽  
M Uchiyama ◽  
T Nobori ◽  
M Hirose ◽  
Y Hayakawa

A general, facile synthesis of 2'-5'-linked oligonucleotides (2-5A oligomers ) has been achieved based on the second-order regioselective protection of adenosine, one-pot formation of the 2'5' internucleotide linkage, and O-selective phosphorylation of N-unblocked nucleosides. Standard t- butyldimethylsilylation of 5'-O-p-methoxytrityladenosine followed by careful recrystallization from a mixture of triethylamine , methanol, ethyl acetate and ether (4 : 4 : 5 : 100 v/v) gives the 3',5'-di-O-protected adenosine in high yield. Magnesium alkoxide -mediated condensation of the 2'-O-free adenosine with o-chlorophenyl p-nitrophenyl phosphorochloridate followed by 2',3'-di-O-t-butyldimethylsilyladenosine produces the N-free and fully O-protected adenylyl (2'-5')adenosine. The resulting adenylyl dimer, after removal of the 5'-O-trityl protector, is elongated to the protected trimeric compound through a similar reaction sequence. Deprotection of the product furnishes the 2-5A core. Condensation of the 5?-0-detritylated core and bis (2,2,2-trichloroethyl) phosphorochloridite assisted by 2,6-lutidine and subsequent oxidation with aqueous iodine produces, after deblocking, 2-5A 5'-monophosphate (p5'A2'p5'pA2'p5'A). The 2-5A 5'-monophosphate is converted into 2-5A 5'-triphosphate (ppp5'A2'p5'A2'p5'A) by reaction with N,N'-carbonyldiimidazole in the presence of triethylamine followed by tributylammonium diphosphate. This procedure allows ready synthesis of 2-5A oligomers and related compounds on a multigram scale.


Author(s):  
Ameen Shahid ◽  
Nesreen S. Ahmed ◽  
Tamer S. Saleh ◽  
Shaeel A. Al-Thabaiti ◽  
Sulaiman N. Basahel ◽  
...  

A sustainable green one pot procedure for the synthesis of dihydropyrimidinones (DHPMs) derivatives by a three-component reaction of β-ketoester derivatives, aldehyde and urea or thiourea over the alkali-treated H-ZSM-5 zeolite under ball-milling has been developed. The product was isolated by simple washing of the crude reaction residue with ethyl acetate followed by evaporation of solvent. The hierachical zeolite catalyst (MFI27_6) showed high yield (86–96%) of dihydropyrimidinones (DHPMs), in very short time (10-30 min). The catalyst is recycled for subsequent reactions in four runs without appreciable loss of activity and high yields of products provide efficient protocol for Biginelli reactions.


2011 ◽  
Vol 334 (1-2) ◽  
pp. 29-34 ◽  
Author(s):  
Priscila C. Zonetti ◽  
Johnatan Celnik ◽  
Sonia Letichevsky ◽  
Alexandre B. Gaspar ◽  
Lucia G. Appel

2020 ◽  
Vol 98 (3) ◽  
pp. 158-163 ◽  
Author(s):  
Toren Hynes ◽  
David S. Hall ◽  
Alexander W.H. Speed ◽  
Jason D. Masuda ◽  
J.R. Dahn

3-R-1,4,2-dioxazol-5-ones are a class of compounds that are increasingly finding diverse uses, including as regioselective amidation reagents and as electrolyte additives that enable long cycling lifetimes in rechargeable lithium-ion batteries. Conventional methods for their synthesis tend to be slow and time-consuming, requiring isolation and thorough drying of a hydroxamic acid intermediate, followed by a separate cyclization step with N,N′-carbonyldiimidazole. Furthermore, the cyclization is typically performed in dichloromethane, an environmentally harmful solvent. This work demonstrates a new one-pot method for the synthesis of these compounds that eliminates the need for isolation of the intermediate or the use of halogenated solvents. The reaction is mainly performed using environmentally benign ethyl acetate and a relatively small amount of N,N-dimethylformamide. The reaction proceeds readily at room temperature and requires no expensive metal catalysts to function.


2019 ◽  
Author(s):  
Nicholas D. C. Tappin ◽  
Weronika Michalska ◽  
Simon Rohrbach ◽  
Philippe Renaud

An operationally simple protocol to affect an atom transfer radical addition (ATRA) of commercially available ICH<sub>2</sub>Bpin to terminal alkenes has been developed. The intermediate iodide can be transformed in a one-pot process into the corresponding cyclopropane upon treatment with tetrabutylammonium fluoride (TBAF). This method is highly selective for the cyclopropanation of unactivated terminal alkenes over non-terminal alkenes and electron deficient alkenes. Due to the mildness of the procedure, a wide range of functional groups such as esters, amides, alcohols, ketones, and vinylic cyclopropanes are well tolerated. The whole reaction sequence relies on simple reagents such dilauroyl peroxide (DLP) and TBAF and can be run on multi-gram scales in ethyl acetate as a solvent.


2020 ◽  
Vol 07 ◽  
Author(s):  
Devendra S. Wagare ◽  
Mujahed Shaikh ◽  
Lingampalle D.L. ◽  
Ayesha Durrani

Background: Green synthesis of furocoumarins in water, PEG-OSO3H used as a recyclable catalyst for the one-pot syntheis in water. avoid used of toxic, lachrymatric and unstablephenacyl bromides instead of that we prepared it in-situ and directly condence with 4-hydroxycoumarins. Objective: PEG-OSO3H found to be an efficient and reusable catalyst for the microwave irradiated one-pot synthesis of 3- Aryl-furo[3,2-c]coumarins in PEG-water as a greener reaction medium. This method found to be rapid, simple, ecofriendly and yield obtained relatively higher than other reported methods. Methods: Aromatic ketones (5 mmol), NBS (5mmol) was added in solution of PEG-OSO3H (10 mol%) in 10 ml water and irradiated under ultrasound at 80-85°C. then solution of 4-hydroxycoumarin (5 mmol) and solution of acetic acid and ammonium acetate (1 ml) were added into it. Reaction mass was further irradiated for 3 min. The reaction mixture was extracted with ethyl acetate (3 x 10ml) and the combined ethyl acetate phase was concentrated under reduced pressure to obtain corresponding 3-Aryl-furo[3,2-c]coumarins. Aqueous layer was reused for the next reactions. Results: It was observed that electrons withdrawing groups (-NO2,-F etc.) on benzene ring of aromatic ketones increases the rate of reactions as well as yield of the products. The IR spectrum of compound 4a showed prominent peaks at 1737cm-1C=O stretching for lactone, 1H NMR of compound 4c showed characteristic singlets for –CH3 of methoxy group of at 3.94 ppm, The above spectral data confirmed the structure of compound. The 13C NMR spectrum of 4b also shows the peaks of CH3, at 23.25 ppm. Conclusion: PEG-OSO3H found to be an efficient and reusable catalyst for the microwave irradiated one-pot synthesis of 3-Aryl-furo[3,2-c]coumarins in PEG-water as a greener reaction medium. This method found to be rapid, simple, ecofriendly and yield obtained relatively higher than other reported methods.


Sign in / Sign up

Export Citation Format

Share Document