scholarly journals Naphthalenes and Quinolines by Domino Reactions of Morita–Baylis–Hillman Acetates

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5168
Author(s):  
Joel K. Annor-Gyamfi ◽  
Ebenezer Ametsetor ◽  
Kevin Meraz ◽  
Richard A. Bunce
Keyword(s):  
Aromatic Ring ◽  
Control Experiment ◽  
Ring Closure ◽  
Side Chain ◽  
Initial Reaction ◽  
Domino Reactions ◽  
Initial Product ◽  
Michael Acceptor ◽  
Active Methylene Compounds ◽  
Active Methylene

An efficient synthetic route to highly functionalized naphthalenes and quinolines has been developed using domino reactions between Morita–Baylis–Hillman (MBH) acetates and active methylene compounds (AMCs) promoted by anhydrous K2CO3 in dry N,N-dimethylformamide (DMF) at 23 °C. The substrates incorporate allylic acetates positioned adjacent to a Michael acceptor as well as an aromatic ring activated toward a SNAr ring closure. A control experiment indicated that the initial reaction was an SN2’-type displacement of a side chain acetoxy by the AMC anion to afford the alkene product bearing the added nucleophile trans to the SNAr aromatic ring acceptor. Thus, equilibration of the alkene geometry of the initial product was required prior to cyclization. Products were isolated in good to excellent yields. Numerous cases (24) are reported, and several mechanistic possibilities are discussed.

scholarly journals Dihydroquinolines, Dihydronaphthyridines and Quinolones by Domino Reactions of Morita-Baylis-Hillman Acetates

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 890
Author(s):  
Joel K. Annor-Gyamfi ◽  
Ebenezer Ametsetor ◽  
Kevin Meraz ◽  
Richard A. Bunce
Keyword(s):  
Aromatic Ring ◽  
Aromatic Amines ◽  
Control Experiment ◽  
Ring Closure ◽  
Domino Reaction ◽  
Side Chain ◽  
Initial Reaction ◽  
Dual Reactivity ◽  
Michael Acceptor ◽  
Nitrogen Nucleophile

An efficient synthetic route to highly substituted dihydroquinolines and dihydronaphthyridines has been developed using a domino reaction of Morita-Baylis-Hillman (MBH) acetates with primary aliphatic and aromatic amines in DMF at 50–90 °C. The MBH substrates incorporate a side chain acetate positioned adjacent to an acrylate or acrylonitrile aza-Michael acceptor as well as an aromatic ring activated toward SNAr ring closure. A control experiment established that the initial reaction was an SN2′-type displacement of the side chain acetate by the amine to generate the alkene product with the added nitrogen nucleophile positioned trans to the SNAr aromatic ring acceptor. Thus, equilibration of the initial alkene geometry is required prior to cyclization. A further double bond migration was observed for several reactions targeting dihydronaphthyridines from substrates with a side chain acrylonitrile moiety. MBH acetates incorporating a 2,5-difluorophenyl moiety were found to have dual reactivity in these annulations. In the absence of O2, the expected dihydroquinolines were formed, while in the presence of O2, quinolones were produced. All of the products were isolated in good to excellent yields (72–93%). Numerous cases (42) are reported, and mechanisms are discussed.

scholarly journals Synthesis of Some Heterocyclic Compounds Derived from 2-Mercapto Benzoxazole

2013 ◽  
Vol 10 (3) ◽  
pp. 766-778 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Acetic Acid ◽  
Melting Point ◽  
Heterocyclic Compounds ◽  
Nmr Spectra ◽  
Ring Closure ◽  
Phenyl Isothiocyanate ◽  
Triazole Derivative ◽  
Active Methylene Compounds ◽  
Ft Ir ◽  
Active Methylene

New series of 2-mecapto benzoxazole derivatives (1-20) incorporated into fused to different nitrogen and suphur containing heterocyclic were prepared from 2-meracpto benzoxazole, when treated with hydrazine hydrate to afford 2-hydrazino benzoxazol (1). Compound (1) converted to a variety of pyridazinone andphthalazinone derivatives (2-4) by reaction with different carboxylic anhydride. Also, reaction of (1) with phenyl isothiocyanate and ethyl chloro acetate afforded 3-phenyl-1,3-thiazolidin-2,4-dione-2-(benzoxazole-2-yl-hydrazone) (6). Azomethines (7-10) were prepared through reaction of (1) with aromatic aldehyde, then (7, 8) converted to thaizolidinone derivatives (11, 12). Treatment of (1) with active methylene compounds afforded derivative (13). Reaction of (1) with CS2 and NaOH gave 1,2,4-triazole derivative (14). Treatment of (1) with p-bromophenancyl bromide afforded another 1,2,4-triazole (15). The reaction of 2-mercapto benzoxazole with chloro acetic acid gave (16) followed by refluxing (16) with ortho-amino aniline giving benzimidazol (17). Moreover, the reaction of 2-mercapto benzoxazole with ethyl chloroacetate afforded (18), and then reaction of (18) with thiosemicarbazide and 4% NaOH leads to ring closure giving 1,2,4-triazole derivative (20). All compounds were confirmed by their melting point, FT-IR, UV-Vis spectra and 1H-NMR spectra for some of them.

scholarly journals Synthesis of Some Heterocyclic Compounds derived from 2-mercapto pyrimidine

2010 ◽  
Vol 7 (2) ◽  
pp. 1014-1022
Author(s):  
Baghdad Science Journal
Keyword(s):  
Acetic Acid ◽  
Benzimidazole Derivative ◽  
Aromatic Aldehydes ◽  
Uv Spectra ◽  
Ring Closure ◽  
Phenyl Isothiocyanate ◽  
Element Analysis ◽  
Active Methylene Compounds ◽  
Active Methylene ◽  
Tetrazole Derivatives

In this work 2-hydrazino pyrimidine (1) was prepared from 2-mercapto pyrimidine with hydrazine hydrate. Treatment of (1) with active methylene compounds gave 2-(3,5-dimethyl -1 H – Pyrazole-1-yl) pyrimidine , whereas the reaction of (1) with carboxylic anhydride namely maleic anhydride or 1,2,3,6-tetra hydro phthalic anhydride yielded 1-Pyrimidine-2-yl-1,2-dihydro pyridazine-3,6-dione (3) and 2 – Pyrimidin -2-yl -2,3,4 a ,5,8 a – hexahydro phthalazine 1,4 – dione (4) . Reaction of (1) with phenyl isothiocyanate and ethyl chloro acetate afforded 3-Phenyl-1,3-thiazolidine-2,4-dione-2( pyrimidine -2- yl hydrazone (6) Azomethine (7-10) were prepared through condensation of (1) with aromatic aldehydes or ketones, then compounds (7-9) are converted into a number of tetrazole derivatives (11-13). Treatment of (1) with acetic acid afforded the derivative (14) . The reaction of 2-mercapto pyrimidine with ethyl chloro acetate afforded (15),whereas the reaction of (15) with thiosemicarbazide and 4% sodum hydroxide leads to ring closure giving 1,2,4 triazole derivative (17). Moreover the reaction of 2-mercapto pyrimidine with chloro acetic acid gave (18) followed by refluxing (18) with o- amino aniline to give the benzimidazole derivative (19).the structure of these compounds were characterized by FR-IR, UV spectra and some of them were characterized by element analysis.

scholarly journals Renal sodium-potassium adenosine triphosphatase. Optical localization and x-ray microanalysis.

1975 ◽  
Vol 23 (11) ◽  
pp. 828-839 ◽  
Author(s):  
R Beeuwkes ◽  
S Rosen
Keyword(s):  
Atpase Activity ◽  
Electron Probe ◽  
Sequential Analysis ◽  
Relative Sensitivity ◽  
Initial Reaction ◽  
Initial Product ◽  
Sodium Potassium ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of ◽  
Convoluted Tubules

The distribution of sodium-potassium adenosine triposphatase (Na-K-ATPase) activity in kidney sections has been studied by a method based on the hydrolysis of p-nitrophenyl phosphate in alkaline medium containing dimethyl sulfoxide. The products at each stage in the reaction sequence have been subjected to electron probe microanalysis. The initial product was identified as a mixture of KMgPO4 and Mg(PO4)2, and sequential analysis demonstrated the linearity of conversion of this product to a visible form. In human, rabbit and rat kidneys the distribution of activity was found to be essentially identical, with highest levels located in thick ascending limbs and distal convoluted tubules. The initial reaction was completely potassium dependent and was inhibited by ouabain in concentrations reflecting the relative sensitivity of microsomal Na-K-ATPase in each species. Measurement of initial product phosphorus by means of the electron probe is presented as a practical technique for direct quantitation of Na-K-ATPase activity in identified tubule segments.

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