Synthesis of Pyrazinopyrazine-Fused Azaacenes through Direct Condensation Reactions between Quinoxalinediamine and Diketones

2020 ◽  
Vol 85 (10) ◽  
pp. 6372-6379
Author(s):  
Yuping Yuan ◽  
Kin-Cheung Lo ◽  
Lap Szeto ◽  
Wai-Kin Chan
Keyword(s):  
Condensation Reactions ◽  
Direct Condensation

An improved procedure for the preparation of 3-carbometfaoxy-4-oxotetrahydrothiopyran, 2- and 4-carbomethoxy-3-oxotetrahydrothiophene

1982 ◽  
Vol 60 (4) ◽  
pp. 437-439 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Teng Ko Ngooi
Keyword(s):  
Methyl Methacrylate ◽  
Methyl Acrylate ◽  
Good Yield ◽  
Sodium Hydride ◽  
Major Product ◽  
Condensation Reactions ◽  
Lower Temperature ◽  
Direct Condensation

An improved procedure for the preparation of the title compounds 1-3 has been developed. Direct condensation of methyl 3-mercaptopropionate with methyl acrylate using sodium hydride as a base gave compound 1 in good yield. The reaction of methyl thioglycolate and methyl acrylate at 0 °C gave compound 2 as the major product whereas at lower temperature (−40 °C) isomer 3 was found as the major product. The condensation reactions of methyl thioglycolate with methyl methacrylate and crotonate were also carried out.

Knoevenagel Condensation Reactions of Cyano Malononitrile-Derivatives Under Microwave Radiation

2018 ◽  
Vol 22 (6) ◽  
pp. 519-532 ◽  
Author(s):  
Lucas Lima Zanin ◽  
David Esteban Quintero Jimenez ◽  
Luis Pina Fonseca ◽  
Andre Luiz Meleiro Porto
Keyword(s):  
Microwave Radiation ◽  
Knoevenagel Condensation ◽  
Condensation Reactions

Total Synthesis and Antibacterial Screening of (±)-6,8-Dihydroxy-3- undecyl-3,4-dihydroisochromen-1-one: A Structural Analogue of Metabolites from Ononis natrix

2019 ◽  
Vol 16 (3) ◽  
pp. 245-248
Author(s):  
Hummera Rafique ◽  
Aamer Saeed ◽  
Ehsan Ullah Mughal ◽  
Muhammad Naveed Zafar ◽  
Amara Mumtaz ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Structural Analog ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Antibacterial Screening ◽  
Maximum Inhibition ◽  
Bacillus Subtilus ◽  
Hydrolysis Of ◽  
Direct Condensation

Background: (±)-6,8-Dihydroxy-3-undecyl-3,4-dihydroisochromen-1-one is one of the structural analog of several substituted undecylisocoumarins isolated from Ononis natrix (Fabaceae), has been successfully synthesized by direct condensation of homopthalic acid (1) with undecanoyl chloride yields isochromen-1-one (2). Methods: Alkaline hydrolysis of (2) gave the corresponding keto-acid (3), which is then reduced to hydroxy acid (4) then its cyclodehydration was carried out with acetic anhydride to afford 3,4- dihydroisochromen-1-one (5). Followed by demethylation step, the synthesis of target 6,8- dihydroxy-7-methyl-3-undecyl-3,4-dihydroisocoumarin (6) was achieved. Results: In vitro antibacterial screening of all the synthesized compounds were carried out against ten bacterial strains by agar well diffusion method. Conclusion: Newly synthesized molecules exhibited moderate antibacterial activity and maximum inhibition was observed against Bacillus subtilus and Salmonella paratyphi.

Influence of Metal Core Composition on Redox Properties and Photoreactivity of the Clusters [H4-xRu4-xRhx(CO)12] (x = 0, 2, 3, 4)

2001 ◽  
Vol 66 (7) ◽  
pp. 1062-1077 ◽  
Author(s):  
Maarten J. Bakker ◽  
Tapani A. Pakkanen ◽  
František Hartl
Keyword(s):  
Electrochemical Properties ◽  
Electrochemical Reduction ◽  
Redox Properties ◽  
Metal Core ◽  
Loss Product ◽  
Condensation Reactions ◽  
Core Composition ◽  
Co Dissociation ◽  
Major Reduction

Electrochemical properties of tetrahedral clusters [H2Ru2Rh2(CO)12], [HRuRh3(CO)12] and [Rh4(CO)12] were investigated in order to evaluate the influence of metal core composition in the series [H4-xRu4-xRhx(CO)12] (x = 0-4). The cluster [H3Ru3Rh(CO)12] was not available in sufficient quantities. As reported for [H4Ru4(CO)12], electrochemical reduction of the hydride-containing clusters [H2Ru2Rh2(CO)12] and [HRuRh3(CO)12] also results in (stepwise) loss of hydrogen, producing the anions [HRu2Rh2(CO)12]-, [Ru2Rh2(CO)12]2- and [RuRh3(CO)12]-. These anions can also be prepared from the neutral parent clusters via chemical routes. Electrochemical reduction of [Rh4(CO)12] does not result in the formation of any stable tetranuclear anion. Instead, [Rh5(CO)15]- and [Rh6(CO)15]2- are the major reduction products detected in the course of IR spectroelectrochemical experiments. Most likely, these cluster species are formed from the secondary CO-loss product [Rh4(CO)11]2- by fast redox condensation reactions. Their reoxidation regenerates parent [Rh4(CO)12], together with some [Rh6(CO)16]. Unlike [H4Ru4(CO)12] that undergoes photochemical CO-dissociation, [H2Ru2Rh2(CO)12] and [Rh4(CO)12] are completely photostable in neat hexane and dichloromethane as well as in the presence of oct-1-ene.

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