scholarly journals A practical way to synthesize chiral fluoro-containing polyhydro-2H-chromenes from monoterpenoids

2016 ◽  
Vol 12 ◽  
pp. 648-653 ◽  
Author(s):  
Oksana S Mikhalchenko ◽  
Dina V Korchagina ◽  
Konstantin P Volcho ◽  
Nariman F Salakhutdinov
Keyword(s):  
Aromatic Aldehydes ◽  
Single Step ◽  
Preparative Synthesis ◽  
Aliphatic Aldehydes ◽  
First Time

Conditions enabling the single-step preparative synthesis of chiral 4-fluoropolyhydro-2H-chromenes in good yields through a reaction between monoterpenoid alcohols with para-menthane skeleton and aldehydes were developed for the first time. The BF3·Et2O/H2O system is used both as a catalyst and as a fluorine source. The reaction can involve aliphatic aldehydes as well as aromatic aldehydes containing various acceptor and donor substituents. 4-Hydroxyhexahydro-2H-chromenes were demonstrated to be capable of converting to 4-fluorohexahydro-2H-chromenes under the developed conditions, the reaction occurs with inversion of configuration.

scholarly journals Broad scope gold(i)-catalysed polyenyne cyclisations for the formation of up to four carbon–carbon bonds

2017 ◽  
Vol 15 (10) ◽  
pp. 2163-2167 ◽  
Author(s):  
Zhouting Rong ◽  
Antonio M. Echavarren
Keyword(s):  
Single Step ◽  
Simultaneous Formation ◽  
Broad Scope ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
First Time ◽  
High Stereoselectivity

The polycyclisation of polyeneynes catalyzed by gold(i) has been extended for the first time to the simultaneous formation of up to four carbon–carbon bonds, leading to steroid-like molecules with high stereoselectivity in a single step with low catalyst loadings.

scholarly journals Versatile precursor dependent copper sulfide nanoparticles as multifunctional catalyst for photocatalytic removal of water pollutants and synthesis of aromatic aldehydes and NH-triazoles

2021 ◽  
Author(s):  
Soniya Agarwal ◽  
Parmita Phukan ◽  
Diganta Sarma ◽  
Kalyanjyoti Deori
Keyword(s):  
Copper Sulfide ◽  
Aromatic Aldehydes ◽  
Water Pollutants ◽  
Photocatalytic Removal ◽  
Multifunctional Catalyst ◽  
First Time

A series of copper sulfide (CS) nanoparticles (NPs) were synthesized just by varying the amount of sulfur precursor and have been explored for the first time as a three way...

scholarly journals Radical Dehalogenation and Purine Nucleoside Phosphorylase E. coli: How Does an Admixture of 2′,3′-Anhydroinosine Hinder 2-fluoro-cordycepin Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 539
Author(s):  
Alexey L. Kayushin ◽  
Julia A. Tokunova ◽  
Ilja V. Fateev ◽  
Alexandra O. Arnautova ◽  
Maria Ya. Berzina ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Preparative Synthesis ◽  
Nucleoside Phosphorylase ◽  
E Coli ◽  
First Time

During the preparative synthesis of 2-fluorocordycepin from 2-fluoroadenosine and 3′-deoxyinosine catalyzed by E. coli purine nucleoside phosphorylase, a slowdown of the reaction and decrease of yield down to 5% were encountered. An unknown nucleoside was found in the reaction mixture and its structure was established. This nucleoside is formed from the admixture of 2′,3′-anhydroinosine, a byproduct in the preparation of 3-′deoxyinosine. Moreover, 2′,3′-anhydroinosine forms during radical dehalogenation of 9-(2′,5′-di-O-acetyl-3′-bromo- -3′-deoxyxylofuranosyl)hypoxanthine, a precursor of 3′-deoxyinosine in chemical synthesis. The products of 2′,3′-anhydroinosine hydrolysis inhibit the formation of 1-phospho-3-deoxyribose during the synthesis of 2-fluorocordycepin. The progress of 2′,3′-anhydroinosine hydrolysis was investigated. The reactions were performed in D2O instead of H2O; this allowed accumulating intermediate substances in sufficient quantities. Two intermediates were isolated and their structures were confirmed by mass and NMR spectroscopy. A mechanism of 2′,3′-anhydroinosine hydrolysis in D2O is fully determined for the first time.

Pt NPs@GO as a highly efficient and reusable catalyst for one-pot synthesis of acridinedione derivatives

RSC Advances ◽  
2015 ◽  
Vol 5 (61) ◽  
pp. 49295-49300 ◽  
Author(s):  
Handan Pamuk ◽  
Burak Aday ◽  
Fatih Şen ◽  
Muharrem Kaya
Keyword(s):  
Aromatic Aldehydes ◽  
Reusable Catalyst ◽  
One Pot ◽  
Highly Efficient ◽  
One Pot Synthesis ◽  
First Time

Pt NPs@GO has been used for the first time for synthesizing acridinedione from dimedone, aromatic aldehydes and various amines as a catalyst.

scholarly journals Synthesis of new Cα-tetrasubstituted α-amino acids

2009 ◽  
Vol 5 ◽  
Author(s):  
Andreas A Grauer ◽  
Burkhard König
Keyword(s):  
Amino Acids ◽  
Secondary Structure ◽  
Aromatic Aldehydes ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Peptide Backbone ◽  
Aliphatic Aldehydes ◽  
New Class ◽  
Cyclic Amino Acids

Cα-Tetrasubstituted α-amino acids are important building blocks for the synthesis of peptidemimetics with stabilized secondary structure, because of their ability to rigidify the peptide backbone. Recently our group reported a new class of cyclic Cα-tetrasubstituted tetrahydrofuran α-amino acids prepared from methionine and aromatic aldehydes. We now report the extension of this methodology to aliphatic aldehydes. Although such aldehydes are prone to give aldol products under the reaction conditions used, we were able to obtain the target cyclic amino acids in low to moderate yields and in some cases with good diastereoselectivity.

Tin(II)chloride Mediated Addition Reaction of Bromonitromethane to Aldehydes

2005 ◽  
Vol 60 (4) ◽  
pp. 416-418 ◽  
Author(s):  
Ali S. Mahasneh
Keyword(s):  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Addition Reaction ◽  
Aromatic Aldehydes ◽  
Aliphatic Aldehydes ◽  
Type Reaction ◽  
High Yields

Bromonitromethane adds to aliphatic aldehydes in the presence of tin(II) chloride to yield β -nitro alcohols via a Reformatsky-type reaction in high yields, while aromatic aldehydes give low yields. The products were characterized by IR, NMR, and mass spectroscopy and by elemental analysis

Single-step conversion of silathiogermylene to germaacid anhydrides: unusual reactivity

2015 ◽  
Vol 51 (20) ◽  
pp. 4310-4313 ◽  
Author(s):  
Surendar Karwasara ◽  
Dhirendra Yadav ◽  
Chandan Kumar Jha ◽  
Gopalan Rajaraman ◽  
Selvarajan Nagendran
Keyword(s):  
Oxidative Addition ◽  
Single Step ◽  
First Time

Single-step conversion of germylene (2) to germaacid anhydrides (3 and 4) is achieved through oxidative-addition with S/Se that involves condensation for the first time.

RÉACTION DU SULFURE DE BORE AVEC QUELQUES GROUPES CARBONYLES

1964 ◽  
Vol 42 (8) ◽  
pp. 1928-1935 ◽  
Author(s):  
S. Jerumanis ◽  
J. M. Lalancette
Keyword(s):  
Good Yield ◽  
Aromatic Aldehydes ◽  
Methyl Benzoate ◽  
Active Hydrogen ◽  
Aliphatic Aldehydes ◽  
Inert Substance

The reactions of boron sulphide with some types of carbonyls have been studied. The reaction of boron sulphide with aromatic aldehydes and aliphatic aldehydes which have been deprived of active hydrogen in the α position gives a good yield of the corresponding trithioaldehydes. This reaction is examined for four aldehydes, namely, benzaldehyde, 3-methylbenzaldehyde, 3-nitrobenzaldehyde, and 2,2′-dimethylpropionaldehyde. Through this study the authors have brought out a method which enables either the α-trithiobenzaldehyde, m.p. 166–167 °C, or the β-trithiobenzaldehyde, m.p. 225–226 °C, to be obtained selectively. The reaction of 3-methylbenzaldehyde with boron sulphide yields only one β stereoisomer, but nitrobenzaldehyde remains completely inert. The aldehydes having one active hydrogen in the α position undergo a dehydrogenation at the same time as the oxygen is being replaced by one atom of sulphur. 2,2′-Dimethylthiopropanal exists in a trimeric state at normal temperatures and becomes monomeric at higher temperatures, whereas the trithiobenzaldehydes do not depolymerize. Methyl benzoate reacts with boron sulphide to give tetraphenyldioxadiene. The structure of this extremely inert substance has been established mainly by physical means: infrared, ultraviolet, and n.m.r. spectra. The reaction of benzophenone and acetophenone with boron sulphide has been investigated. The former has been found inert to the action of the sulphide, and the latter reacts quite readily to give 2,4-diphenylthiophene. The structure of this thiophene is established by desulphuration over nickel. The role of boron sulphide as dehydrogenating and deoxygenating agent is discussed, and a laboratory preparation of boron sulphide is described.

scholarly journals Synthesis of Bis-2,3-dihydroquinazolin-4(1H)-ones and 2,3-Dihydroquinazolin-4(1H)-ones Derivatives with the Aid of Silica-Supported Preyssler Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Ali Gharib ◽  
Bibi Robabeh Hashemipour Khorasani ◽  
Manouchehr Jahangir ◽  
Mina Roshani ◽  
Reza Safaee
Keyword(s):  
Primary Amine ◽  
Ammonium Carbonate ◽  
Aromatic Aldehydes ◽  
Product Yield ◽  
Primary Amines ◽  
Isatoic Anhydride ◽  
One Pot ◽  
High Yields ◽  
First Time

One-pot three-component condensation of isatoic anhydride with primary amines or ammonium carbonate and aromatic aldehydes in refluxing ethanol in the presence of catalytic amounts of silica-supported preyssler nanoparticles (SPNP) afforded the corresponding 2,3-dihydroquinazolin-4(1H)-ones in high yields, and bis-dihydroquinazolinones were synthesized for the first time by a novel pseudo-five-component condensation of isatoic anhydride, a primary amine, and a dialdehyde in water. The catalyst is reusable and can be applied several times without any decrease in product yield.

A nitrate biosensor based methodology for monitoring anoxic activated sludge activity

2004 ◽  
Vol 50 (11) ◽  
pp. 125-133 ◽  
Author(s):  
G. Sin ◽  
P.A. Vanrolleghem
Keyword(s):  
Activated Sludge ◽  
Uptake Rate ◽  
High Frequency ◽  
Single Step ◽  
High Time Resolution ◽  
High Data ◽  
Start Up ◽  
Monitoring Process ◽  
Nitrate Uptake Rate ◽  
First Time

An improved methodology based on a nitrate biosensor is developed and applied successfully for in-depth monitoring and study of anoxic activated sludge activities. The major advantages of the methodology are its simplicity, reliability and high data quality. The resulting data allowed for the first time to monitor anoxic respiration rate of activated sludge (nitrate uptake rate (NUR)) at a high time resolution making it clearly comparable with high frequency oxygen uptake rate (OUR) measurements obtained under aerobic conditions. Further, the anoxic respiration data resulting from a pulse addition of carbon source to endogenously respiring anoxic activated sludge shows a clear start-up phenomenon and storage tail that is usually also observed in high-frequency OUR measurements. Finally, the improved methodology can be expected to serve as an anoxic respirometer for activated sludge treatment plants where denitrification process occurs in single-step. Further, it can be used for a variety of purposes e.g. for toxicity and activity monitoring, process control and parameter estimation of the activated sludge process, similar to the aerobic respirometers.

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