Chemistry of kojic acid: One-step syntheses of benzothiazoles and other fused heterocycles from kojic acid derivatives

1983 ◽  
Vol 36 (11) ◽  
pp. 2307 ◽  
Author(s):  
T Teitei
Keyword(s):  
Kojic Acid ◽  
Benzyl Ether ◽  
Pyridine Derivatives ◽  
Reaction Products ◽  
Fused Heterocycles ◽  
One Step ◽  
Mechanism Of The Reaction

The reactions of the benzyl ether (1b) of kojic acid (la) and its chloromethyl derivative (1c) were investigated as new routes to fused heterocyclic systems. The chloromethyl compound proved the more versatile intermediate yielding benzothiazoles with thiourea and pyrido[l,2-a]benzimidazoles (11) and pyrido[1,2-alindole (12b) with pyridine derivatives. A number of methylated products of the benzothiazole were prepared in order to establish the structures of the reaction products and a possible mechanism of the reaction is discussed.

One-Step Directional Cloning of Blunt-Ended Polymerase Chain Reaction Products

2000 ◽  
Vol 287 (2) ◽  
pp. 349-352 ◽  
Author(s):  
Vincent W.S. Liu ◽  
Phillip Nagley ◽  
Hextan Y.S. Ngan
Keyword(s):  
Polymerase Chain Reaction ◽  
Reaction Products ◽  
Chain Reaction ◽  
Directional Cloning ◽  
One Step ◽  
Polymerase Chain

Pentacarbonylmanganese enolate and dienolate complexes. Preparative and mechanistic considerations

1990 ◽  
Vol 68 (3) ◽  
pp. 492-501 ◽  
Author(s):  
Andrew P. Masters ◽  
Ted S. Sorensen
Keyword(s):  
Nmr Spectroscopy ◽  
Nucleophilic Substitution ◽  
Reaction Products ◽  
Organic Products ◽  
Mechanism Of The Reaction ◽  
Model Reactions ◽  
Inorganic And Organic

Reactions of pentacarbonyl manganate anion with 4-halocrotonate esters or 2-halocarboxylate esters result in a complex set of inorganic and organic products, usually including the expected dienolate (or enolate) complexes. The reaction variables include the counterion, solvent, and halo group. The mechanism of the reaction has been investigated by conducting a thorough characterization of the reaction products under various conditions and also by carrying out model reactions. One can rationalize most of the non-organometallic products using either a radical or carbanion mechanism, but the latter seems to fit the available data better. Experimental procedures for optimizing the yield of the organometallic dienolate or enolate complexes have been worked out. Keywords: pentacarbonyl manganate, metalate nucleophilicity, enolate complex, nucleophilic substitution, 55Mn NMR spectroscopy.

Ruthenium-Catalyzed Synthesis of Pyrrolo[1,2-a]quinoxaline Derivatives from 1-(2-Aminophenyl)pyrroles and Sulfoxonium Ylides

Synlett ◽  
2020 ◽  
Vol 31 (12) ◽  
pp. 1205-1210 ◽  
Author(s):  
Guo-Sheng Huang ◽  
Xin-Feng Cui ◽  
Fang-Peng Hu ◽  
Xiao-Qiang Zhou ◽  
Zhen-Zhen Zhan
Keyword(s):  
Reaction Time ◽  
Functional Group ◽  
Reaction Pathway ◽  
Ambient Conditions ◽  
Step Method ◽  
Short Reaction Time ◽  
Quinoxaline Derivatives ◽  
One Step ◽  
Preliminary Study ◽  
Mechanism Of The Reaction

A ruthenium-catalyzed [5+1] annulation of 1-(2-aminophenyl)pyrroles with α-carbonyl sulfoxonium ylides is reported. This reaction provides a one-step method for synthesizing pyrrolo[1,2-a]quinoxaline derivatives under ambient conditions. The system proceeds with a short reaction time and a high functional-group tolerance. Notably, this divergent protocol tolerates β-keto sulfoxonium ylides and can be applied to α-ester sulfoxonium ylides. A preliminary study was made of the mechanism of the reaction, and a reaction pathway is proposed.

scholarly journals Easy One-Step Amplification and Labeling Procedure for Copy Number Variation Detection

2020 ◽  
Vol 66 (3) ◽  
pp. 463-473 ◽  
Author(s):  
Sebastián Blesa ◽  
María D Olivares ◽  
Andy S Alic ◽  
Alicia Serrano ◽  
Verónica Lendinez ◽  
...  
Keyword(s):  
Dna Repair ◽  
Copy Number ◽  
Simple Procedure ◽  
Receptor Gene ◽  
Density Lipoprotein ◽  
Copy Number Variations ◽  
Chromosome 17 ◽  
Reaction Products ◽  
One Step ◽  
Cnv Detection

Abstract Background The specific characteristics of copy number variations (CNVs) require specific methods of detection and characterization. We developed the Easy One-Step Amplification and Labeling procedure for CNV detection (EOSAL-CNV), a new method based on proportional amplification and labeling of amplicons in 1 PCR. Methods We used tailed primers for specific amplification and a pair of labeling probes (only 1 labeled) for amplification and labeling of all amplicons in just 1 reaction. Products were loaded directly onto a capillary DNA sequencer for fragment sizing and quantification. Data obtained could be analyzed by Microsoft Excel spreadsheet or EOSAL-CNV analysis software. We developed the protocol using the LDLR (low density lipoprotein receptor) gene including 23 samples with 8 different CNVs. After optimizing the protocol, it was used for genes in the following multiplexes: BRCA1 (BRCA1 DNA repair associated), BRCA2 (BRCA2 DNA repair associated), CHEK2 (checkpoint kinase 2), MLH1 (mutL homolog 1) plus MSH6 (mutS homolog 6), MSH2 (mutS homolog 2) plus EPCAM (epithelial cell adhesion molecule) and chromosome 17 (especially the TP53 [tumor protein 53] gene). We compared our procedure with multiplex ligation-dependent probe amplification (MLPA). Results The simple procedure for CNV detection required 150 min, with <10 min of handwork. After analyzing >240 samples, EOSAL-CNV excluded the presence of CNVs in all controls, and in all cases, results were identical using MLPA and EOSAL-CNV. Analysis of the 17p region in tumor samples showed 100% similarity between fluorescent in situ hybridization and EOSAL-CNV. Conclusions EOSAL-CNV allowed reliable, fast, easy detection and characterization of CNVs. It provides an alternative to targeted analysis methods such as MLPA.

A facile one‐step synthesis of chromeno[4,3‐ b ]pyridine derivatives promoted by niobium pentachloride

2020 ◽  
Vol 57 (7) ◽  
pp. 2795-2800
Author(s):  
Paula B. Oshiro ◽  
Bruna A. Bregadiolli ◽  
Luiz C. Silva‐Filho
Keyword(s):  
Pyridine Derivatives ◽  
Niobium Pentachloride ◽  
One Step

Reactions of Ketene Acetals. IV. A New Synthesis of α-Pyrones. III

1975 ◽  
Vol 53 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Alain Bélanger ◽  
Paul Brassard
Keyword(s):  
New Synthesis ◽  
One Step ◽  
Ketene Acetals ◽  
Mechanism Of The Reaction

A simple one-step synthesis of α-pyrones and 3-chloro-α-pyrones from β-functionalized α, β-enones and ketene acetals has been devised. The method has also been adapted to the preparation of some 4-methoxy-α-pyrones. Finally the mechanism of the reaction has been investigated.

scholarly journals Scandium and Dimethylaminopyridine Catalyzed Dehydrative Coupling of Secondary Benzylic and Primary Alcohols to Synthesize Unsymmetrical Ethers

2020 ◽  
Author(s):  
Julia Duncan ◽  
Lun Li ◽  
Vahid Mohammadrezaei ◽  
Laina Geary
Keyword(s):  
Spectroscopic Data ◽  
Supplementary Information ◽  
Primary Alcohols ◽  
Benzylic Alcohols ◽  
Benzylic Alcohol ◽  
Catalytic Condensation ◽  
Rapid Formation ◽  
One Step ◽  
Insight Into ◽  
Mechanism Of The Reaction

We developed a direct catalytic condensation of benzylic alcohols and primary alcohols to synthesize unsymmetrical ethers in one step, catalyzed by scandium triflate and p-dimethylaminopyridine (DMAP). Preliminary experiments give some insight into the mechanism of the reaction, though suggest that the process is quite complex. We suspect the rapid formation of a dimer from a secondary benzylic alcohol via a carbocation intermediate precedes unsymmetrical ether formation. Full experimental details and spectroscopic data are provided as supplementary information.

scholarly journals Biological Active Esters of the Isovaleric Acid

2014 ◽  
Vol 16 (4) ◽  
Author(s):  
Kh.A. Suerbaev ◽  
G.Zh. Zhaksylykova ◽  
N.O. Appazov
Keyword(s):  
Carbon Monoxide ◽  
New Technologies ◽  
Isovaleric Acid ◽  
Advanced Technology ◽  
Reaction Products ◽  
Drug Synthesis ◽  
One Step ◽  
The Cost ◽  
Carbon Acid ◽  
Acid Esters

<p>Hydroalkoxycarbonylation of olefins with carbon monoxide and alcohols under condition of homogeneous –catalysis with transition metal complexes allows facile one-step synthesis of practically <br /> useful carbon acid esters. Many of them have biological activity and are constituents of drugs or valuable intermediate products in drug synthesis. Hydroalkoxycarbonylation of isobutylene with carbon monoxide and alcohols in the presence of catalytic system Pd(PPh<sub>3</sub>)<sub>4</sub>-PPh<sub>3</sub>-TsOH was applied for preparing of biological active isovaleric acid esters: <em>1</em>-menthylisovalerate (main active component of the spasmolytic medicine “Validolum”), ethylisovalerate (intermediate product for obtaining sedative and spasmolytic medicines “Ethyl ester of <em>α</em>-bromisovaleric acid” and “Corvalolum”), cyclohexylisovalerate (bactericide activity) and benzylisovalerate (bactericide and antifungus activity). Hydroalkoxycarbonylation reaction of isobutylene with carbon monoxide and alcohols (ethanol, cyclohexanol, l-menthol, benzyl alcohol) in the presence Pd(PPh<sub>3</sub>)<sub>4</sub>-PPh<sub>3</sub>-TsOH system carried out at conditions: temperature 100 °C; CO pressure 2.0 MPa; reaction time 4 h; reactants and catalyst components ratio [alcohol]:[isobutylene]:[Pd(PPh<sub>3</sub>)<sub>4</sub>]:[PPh<sub>3</sub>]:[TsOH] = 435:550:1:3:12. The yields of the products were 71-95% (on converted alcohols). The selectivity in linear reaction products was 100%. Such a high regioselectivity is apparently provided both by the structure of the starting alkene (isobutylene) and by the reaction mechanism. The most probable is a hydride mechanism. Due to the more advanced technology of production the Medicines will have better qualitative characteristics. The cost of production of the Medicines with the use of new technologies is 2-3 times lower as compared to the medicines produced by existing at the present traditional technologies.</p>

Sign in / Sign up

Export Citation Format

Share Document