scholarly journals Mild and efficient cyanuric chloride catalyzed Pictet–Spengler reaction

2013 ◽  
Vol 9 ◽  
pp. 1235-1242 ◽  
Author(s):  
Ashish Sharma ◽  
Mrityunjay Singh ◽  
Nitya Nand Rai ◽  
Devesh Sawant
Keyword(s):  
Catalytic Amount ◽  
Nitrogen Atmosphere ◽  
Cyanuric Chloride ◽  
Distinct Advantage ◽  
First Report ◽  
Excellent Yield

A practical, mild and efficient protocol for the Pictet–Spengler reaction catalyzed by cyanuric chloride (trichloro-1,3,5-triazine, TCT) is described. The 6-endo cyclization of tryptophan/tryptamine and modified Pictet–Spengler substrates with both electron-withdrawing and electron-donating aldehydes was carried out by using a catalytic amount of TCT (10 mol %) in DMSO under a nitrogen atmosphere. TCT catalyzed the Pictet–Spengler reaction involving electron-donating aldehydes in excellent yield. Thus, it has a distinct advantage over the existing methodologies where electron-donating aldehydes failed to undergo 6-endo cyclization. Our methodology provided broad substrate scope and diversity. This is indeed the first report of the use of TCT as a catalyst for the Pictet–Spengler reaction.

α-Chymotrypsin-Induced Acetalization of Aldehydes and Ketones with Alcohols

Synthesis ◽  
2020 ◽  
Vol 52 (14) ◽  
pp. 2121-2126
Author(s):  
Zhanggao Le ◽  
Zongbo Xie ◽  
Jin Lan ◽  
Guofang Jiang ◽  
Jiangnan Yang ◽  
...  
Keyword(s):  
Catalytic Amount ◽  
First Report ◽  
Mild Conditions ◽  
Aldehydes And Ketones ◽  
Neutral Conditions ◽  
Induced Reaction ◽  
General Method

This is the first report of a simple and general method for acetalization­ of aldehydes via an α-chymotrypsin-induced reaction under mild conditions. A broad range of aromatic and heteroaromatic aldehydes have been acetalized under neutral conditions in good yields using a catalytic amount of chymotrypsin.

Microwave Enhanced Acetylation of Alcohols

2002 ◽  
Vol 2002 (6) ◽  
pp. 301-302 ◽  
Author(s):  
Ramesh Patnam ◽  
Fang-Rong Chang ◽  
Reen-Yen Kuo ◽  
Wen-Bin Pan ◽  
Yang-Chang Wu
Keyword(s):  
Acetic Anhydride ◽  
Microwave Irradiation ◽  
Catalytic Amount ◽  
Excellent Yield

Microwave irradiation of alcohols with acetic anhydride in the presence of a catalytic amount of NaOH for a few minutes yielded the corresponding acetylated products in excellent yield.

An unsymmetrical covalent organic polymer for catalytic amide synthesis

2020 ◽  
Vol 49 (1) ◽  
pp. 179-186 ◽  
Author(s):  
Deepika Yadav ◽  
Satish Kumar Awasthi
Keyword(s):  
Cyanuric Chloride ◽  
Amide Bond ◽  
Organic Polymer ◽  
First Report ◽  
Amide Synthesis

Herein, we present the first report on the Covalent Organic Polymer (COP) directed non-classical synthesis of an amide bond. An economical route has been chosen for the synthesis of APC-COP using p-aminophenol and cyanuric chloride.

A Metal-Free and Ionic Liquid-Catalyzed Aerobic Oxidative Bromination in Water

2015 ◽  
Vol 68 (3) ◽  
pp. 513 ◽  
Author(s):  
Jian Wang ◽  
Shu-Bin Chen ◽  
Shu-Guang Wang ◽  
Jing-Hua Li
Keyword(s):  
Ionic Liquid ◽  
Aromatic Compounds ◽  
Hydrobromic Acid ◽  
Bromine Atom ◽  
Catalytic Amount ◽  
Atom Economy ◽  
First Report ◽  
Metal Free ◽  
Oxidative Bromination

A metal-free aerobic oxidative bromination of aromatic compounds in water has been developed. Hydrobromic acid is used as a bromine source and 2-methylpyridinium nitrate ionic liquid is used as a recyclable catalyst. Water is used as the reaction mediate. This is the first report of aerobic oxidative bromination using only catalytic amount of metal-free catalyst. This system shows not only high bromine atom economy, but also high bromination selectivity. The possible mechanism and the role of the catalyst in this system have also been discussed.

Ir-Catalyzed Site Selective Borylation of 8-Arylquinolines

Synthesis ◽  
2021 ◽  
Author(s):  
Buddhadeb Chattopadhyay ◽  
Mirja Md Mahamudul Hassan ◽  
Md Emdadul Hoque ◽  
Sayan Dey ◽  
Saikat Guria ◽  
...  
Keyword(s):  
Functional Groups ◽  
Convenient Method ◽  
High Selectivity ◽  
Catalytic Amount ◽  
Excellent Yield ◽  
Reaction Proceeds ◽  
Site Selective ◽  
Excellent Selectivity

We report a convenient method for the highly site selective borylation of 8-arylquinoline. The reaction proceeds smoothly in presence of catalytic amount of [Ir(OMe)(cod)]2 and 2-phenylpyridine derived ligand using bis(pinacolato)diborane as the borylating agent. The reactions occur with high selectivity with many functional groups, providing a series of borylated 8-aryl quinolines with good to excellent yield and excellent selectivity. The borylated compounds formed in this method can be transformed to various important synthons using known transformations.

One pot synthesis of phenanthridines using a palladium-catalyzed cyclization of aromatic ketoximes with aryl iodides via Beckmann rearrangement

RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 45036-45040 ◽  
Author(s):  
Gajula Raju ◽  
Vijayacharan Guguloth ◽  
Battu Satyanarayana
Keyword(s):  
Catalytic Reaction ◽  
Catalytic Amount ◽  
Beckmann Rearrangement ◽  
One Pot ◽  
Excellent Yield ◽  
One Pot Synthesis ◽  
Aryl Iodides ◽  
Palladium Catalyzed

The catalytic reaction of ketoximes with aryl iodides via a Beckmann rearrangement in the presence of a catalytic amount of Pd(OAc)2, Ag2O and ZnBr2 gave substituted phenanthridines in good to excellent yield.

Perfluoroalkylated-Pyridine Catalyzed the Mannich-Type Reaction: An Example on Elimination the Fluorous Solvent Requirement for Fluorous Catalysis

2013 ◽  
Vol 726-731 ◽  
pp. 165-170 ◽  
Author(s):  
Wen Bin Yi ◽  
Chun Cai
Keyword(s):  
Aromatic Amines ◽  
Aromatic Aldehydes ◽  
Catalytic Amount ◽  
Biphasic System ◽  
Environmental Persistence ◽  
Type Reaction ◽  
Excellent Yield ◽  
Fluorous Solvent

The three-component Mannich-type reactions of different ketones with various aromatic aldehydes and aromatic amines proceeds efficiently in the presence of catalytic amount of perfluoroalkylated-pyridine in a fluorous biphasic system without fluorous solvent, which has prompted various concerns involving cost, solvent leaching, and environmental persistence. The reactions give various β-arylamino ketones in good to excellent yield. The catalyst can be recovered by simple cooling and precipitation and used again.

An Efficient Aromatization of 2-Amino-4,5,6,7-tetrahydrobenzo-[b]thiophene-3-carboxylates in Dimethyl Sulfoxide Catalyzed by p-Toluenesulfonic Acid

Synlett ◽  
2015 ◽  
Vol 26 (08) ◽  
pp. 1101-1105 ◽  
Author(s):  
Mehdi Adib ◽  
Mehd Soheilizad ◽  
Saideh Rajai-daryasaraei ◽  
Peiman Mirzaei
Keyword(s):  
Dimethyl Sulfoxide ◽  
Oxidation Reaction ◽  
Condensation Reaction ◽  
Catalytic Amount ◽  
Excellent Yield ◽  
Toluenesulfonic Acid

A novel oxidation–aromatization of alkyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylates is reported. The Gewald product, obtained from three-component condensation reaction between a cyclohexanone, an alkyl cyanoacetate, and sulfur, underwent an oxidation reaction in dimethyl sulfoxide in the presence of a catalytic amount of p-toluenesulfonic acid to give the corresponding alkyl 2-aminobenzo[b]thiophene-3-carboxylate in excellent yield.

A fossil Aspergillus from Eocene Dominican amber

1988 ◽  
Vol 62 (01) ◽  
pp. 141-143 ◽  
Author(s):  
Gerard M. Thomas ◽  
George O. Poinar
Keyword(s):  
Dominican Republic ◽  
Fossil Species ◽  
First Report ◽  
Dominican Amber ◽  
Eocene Amber

A sporulating Aspergillus is described from a piece of Eocene amber originating from the Dominican Republic. The Aspergillus most closely resembles a form of the white spored phase of Aspergillus janus Raper and Thom. This is the first report of a fossil species of Aspergillus.

Novel magneto-optical recording materials: Bi-substituted garnet films

1991 ◽  
Vol 49 ◽  
pp. 776-777
Author(s):  
Takao Suzuki ◽  
Hossein Nuri
Keyword(s):  
Grain Size ◽  
Amorphous Film ◽  
Nitrogen Atmosphere ◽  
Optical Recording ◽  
Garnet Film ◽  
Media Noise ◽  
Garnet Films ◽  
Order Of Magnitude ◽  
A New Technique ◽  
A Current

For future high density magneto-optical recording materials, a Bi-substituted garnet film ((BiDy)3(FeGa)5O12) is an attractive candidate since it has strong magneto-optic effect at short wavelengths less than 600 nm. The signal in read back performance at 500 nm using a garnet film can be an order of magnitude higher than a current rare earth-transition metal amorphous film. However, the granularity and surface roughness of such crystalline garnet films are the key to control for minimizing media noise.We have demonstrated a new technique to fabricate a garnet film which has much smaller grain size and smoother surfaces than those annealed in a conventional oven. This method employs a high ramp-up rate annealing (Γ = 50 ~ 100 C/s) in nitrogen atmosphere. Fig.1 shows a typical microstruture of a Bi-susbtituted garnet film deposited by r.f. sputtering and then subsequently crystallized by a rapid thermal annealing technique at Γ = 50 C/s at 650 °C for 2 min. The structure is a single phase of garnet, and a grain size is about 300A.

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