Thermal Cyclization of 3-(1-Naphthyl)-1-phenylpyrazole-4-carboxylic Acid in Polyphosphoric Acid.

ChemInform ◽  
2003 ◽  
Vol 34 (18) ◽  
Author(s):  
M. K. Bratenko ◽  
V. A. Chornous ◽  
M. V. Vovk
Keyword(s):  
Carboxylic Acid ◽  
Polyphosphoric Acid ◽  
Thermal Cyclization

Cyclization of Phenacyl 2-{[2,2-Di(ethoxycarbonyl)vinyl]amino}benzoate

1998 ◽  
Vol 63 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Pavel Hradil ◽  
Lubomír Kvapil ◽  
Jan Hlaváč ◽  
Karel Lemr ◽  
Juraj Ševčík
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Ethyl Ester ◽  
Polyphosphoric Acid ◽  
Diphenyl Ether ◽  
Thermal Cyclization ◽  
Prolonged Heating ◽  
Independent Synthesis ◽  
Hydrolysis Of

Reaction of phenacyl anthranilate (1) with diethyl (ethoxymethylidene)malonate afforded phenacyl 2-{[2,2-di(ethoxycarbonyl)vinyl]amino}benzoate (2) which on heating in polyphosphoric acid underwent degradation. Thermal cyclization of 2 in diphenyl ether gave phenacyl 3-(ethoxycarbonyl)-4-oxo-1,4-dihydroquinoline-8-carboxylate (4). The phenacyl group did not cyclize even on prolonged heating at 250 °C. Heating in sulfuric acid resulted in hydrolysis of the ethyl ester under formation of 4-oxo-8-[(phenacyloxy)carbonyl]-1,4-dihydroquinoline-3-carboxylic acid (6). The structure of 4 was confirmed by an independent synthesis.

Addition-cyclization reactions of ethyl isothiocyanatoacetate with carboxylic acid hydrazides

1987 ◽  
Vol 52 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Miroslav Veverka ◽  
Miroslav Marchalín
Keyword(s):  
Carboxylic Acid ◽  
Sodium Ethoxide ◽  
Cyclization Reaction ◽  
Thermal Cyclization ◽  
Cyclization Reactions ◽  
Effect Of Substituents

Ethyl (3-substituted 5-thioxo-1,2,4-triazolin-4-yl)acetates were prepared by addition-cyclization reaction of ethyl isothiocyanatoacetate with carboxylic acid hydrazides in the presence of sodium ethoxide. Thermal cyclization of the adduct in dimethylformamide afforded 1-acetamido-2-thiohydantoin. The effect of substituents on the cyclization course and the thione-thiol tautomerism are discussed.

Synthesis of 2-Substituted-6,7-dimethoxy- and 6,7,8-Trimethoxy-3-hydroxyquinolin-4(1H)-ones

1999 ◽  
Vol 64 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Pavel Hradil ◽  
Jan Vaněček ◽  
Jan Hlaváč ◽  
Juraj Ševčík
Keyword(s):  
Nmr Spectroscopy ◽  
Polyphosphoric Acid ◽  
New Method ◽  
Thermal Cyclization ◽  
H Nmr ◽  
Nitro Derivatives ◽  
Phenacyl Esters

Acetonyl and phenacyl esters of 4,5-dimethoxy- and 3,4,5-trimethoxyanthranilic acids 3 were prepared by reduction of corresponding nitro derivatives 2. Acetonyl 4,5-dimethoxyanthranilate (3a) was prepared by reaction of 4,5-dimethoxyanthranilic acid and chloroacetone. Cyclization of these acetonyl and phenacyl esters in polyphosphoric acid provided the corresponding 2-substituted-6,7-dimethoxy- and 6,7,8-trimethoxy-3-hydroxyquinolin-4(1H)-ones 4. A new method of the thermal cyclization is also described. The structure of the prepared compounds was confirmed by 1H NMR spectroscopy.

Friedel–Crafts Chemistry. Part 39. Unprecedented Facile Route to the Synthesis of Benzo[b][1]benzazepines via Intramolecular Friedel–Crafts Cyclialkylations

2013 ◽  
Vol 66 (6) ◽  
pp. 635 ◽  
Author(s):  
Hassan A. K. Abd El-Aal ◽  
Ali A. Khalaf
Keyword(s):  
Carboxylic Acid ◽  
Polyphosphoric Acid ◽  
Grignard Reagents ◽  
Acid Catalysts ◽  
Efficient Access ◽  
Acid Esters ◽  
Facile Route

A series of six pharmaceutically promising 5,6-dihydro-11H-benzo[b][1]benzazepine derivatives (1c–h) were cleanly prepared by Friedel–Crafts cyclialkylations of nitrogen-containing alkanols in the presence of AlCl3, 85 % H2SO4 or polyphosphoric acid catalysts. The precursor alkanols (13a–f) were readily prepared by reaction of two synthesized carboxylic acid esters (12a, b) with different Grignard reagents. Also, two dibenzo[b,f]azepinones (15a, b) were prepared by Friedel–Crafts cycliacylation and reduced to the corresponding 5,6-dihydro-11H-benzo[b][1]benzazepines (1a, b). Overall, this approach allows easy and efficient access to polytricyclic amines from easily synthesized alkanols or cycloketones. A plausible carbocation mechanism is proposed to account for the results.

Friedel–Crafts Chemistry. Part 46. Unprecedented Construction of Tricyclic Pyrazolo[3,4-b]quinolines, -[1,8]naphthyridines, -azepines, -azocines, -pyrido[3,2-g]azocines, and pyrazolo[3,4-b]azonines via Friedel–Crafts Ring Closures

2016 ◽  
Vol 69 (6) ◽  
pp. 652 ◽  
Author(s):  
Hassan A. K. Abd El-Aal ◽  
Ali A. Khalaf
Keyword(s):  
Carboxylic Acid ◽  
Polyphosphoric Acid ◽  
Acid Catalysts ◽  
Coupling Reactions ◽  
The Novel ◽  
Aryl Amines ◽  
Novel Structures

A series of keto-substituted pyrazolo[3,4-b]quinolines, pyrazolo[3,4-b][1,8]naphthyridines, benzo[e]pyrazolo[3,4-b]azepines, benzo[g]pyrazolo[3,4-b]azocines, pyrazolo[3,4-b]pyrido[3,2-g]azocines, and benzo[g]pyrazolo[3,4-b]azonines scaffolds were synthesized via a Friedel–Crafts cyclialkylation approach. The precursor acids were obtained by utilizing the modified Ullman coupling reactions of 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid with different aryl amines followed by ring closures in the presence of AlCl3/CH3NO2 or P2O5 or polyphosphoric acid catalysts. Particular attention is given to the novel structures especially in regard to the promising pharmaceutical and therapeutic values associated with their skeletons.

Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

1969 ◽  
Vol 21 (02) ◽  
pp. 294-303 ◽  
Author(s):  
H Mihara ◽  
T Fujii ◽  
S Okamoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Carboxylic Acid ◽  
Fibrinolytic Activity ◽  
Clinical Implications ◽  
Trans Form ◽  
Plate Method ◽  
Blood Samples ◽  
Fibrin Plate ◽  
The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

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