Isocarbostyrils. I. Electrophilic Substitution Reactions

1971 ◽  
Vol 49 (17) ◽  
pp. 2785-2796 ◽  
Author(s):  
D. E. Horning ◽  
G. Lacasse ◽  
J. M. Muchowski
Keyword(s):  
Acetic Acid ◽  
Melting Point ◽  
Electrophilic Substitution ◽  
Aqueous Acetic Acid ◽  
Substitution Reactions ◽  
Normal Product ◽  
Mild Conditions ◽  
Acid Catalyzed ◽  
Considerable Detail ◽  
Sole Product

The electrophilic substitution of N-alkylated isocarbostyrils was examined in considerable detail. Bromination, acylation, nitration, and acid-catalyzed condensation with formaldehyde occurred exclusively at C-4 under relatively mild conditions. The acylation of isocarbostyrils has heretofore not been reported.The bromination of 2-methyl-5-nitroisocarbostyril in aqueous acetic acid gave 2-methyl-3,4-dihydro-3-hydroxy-4-bromo-5-nitroisocarbostyril (7) of unknown stereochemistry, as the sole product. When heated above its melting point, 7 lost the elements of water to give the "normal" product of bromination 8.In aqueous acetic acid, excess bromine was shown to convert isocarbostyrils to the corresponding 3,4-dihydro-3-hydroxy-4,4-dibromo derivatives whose structures were supported by spectral and degradative evidence.

Oxidation of α-Hydroxy Acids with Quinolinium Dichromate - A Kinetic Study

1993 ◽  
Vol 58 (7) ◽  
pp. 1624-1630 ◽  
Author(s):  
Kailasa Aruna ◽  
Prerepa Manikyamba ◽  
Embar Venkatachari Sundaram
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Bond Cleavage ◽  
Low Dielectric Constant ◽  
Aqueous Acetic Acid ◽  
Hydroxy Acids ◽  
First Order ◽  
Low Dielectric ◽  
Chloro Derivative ◽  
Acid Catalyzed

Oxidation of lactic acid, α-hydroxyphenyllacetic acid and its 4-chloro derivative with quinolinium dichromate (QDC) in 30% (v/v) aqueous acetic acid at 303 K are first order in QDC and first-order in hydroxy acids. The reactions are acid-catalyzed and a medium of low dielectric constant favours the oxidation. The products are the corresponding aldehydes. Thermodynamic parameters are evaluated and a mechanism involving a C-C bond cleavage is proposed.

ELECTROPHILIC REACTIONS OF STEROIDAL AND OTHER α-PHENYL DIENES

1966 ◽  
Vol 44 (19) ◽  
pp. 2233-2239
Author(s):  
Maurice Douek ◽  
George Just
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Perchloric Acid ◽  
Electrophilic Substitution ◽  
Aluminium Chloride ◽  
Substitution Reactions ◽  
Electrophilic Reactions ◽  
Electrophilic Substitution Reactions

3-Phenylcholesta-3,5-diene (I) is shown to undergo electrophilic substitution reactions exclusively at the 6 position with formaldehyde – perchloric acid, acetic anhydride – aluminium chloride, and the Vilsmeier reagent.In the case of formaldehyde, the final product is "dimmer" II. The reaction is specific for formaldehyde and can be used to detect trace amounts of formaldehyde in, for example, commercial acetic acid and acetic anhydride.

Acid-catalyzed migration of N4-acyl groups in cytosine derivatives

1979 ◽  
Vol 44 (6) ◽  
pp. 1819-1827 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acetic Acid ◽  
Trifluoroacetic Acid ◽  
The Other ◽  
Aqueous Acetic Acid ◽  
Amino Group ◽  
Benzoyl Group ◽  
Benzoyl Cyanide ◽  
Acid Catalyzed ◽  
Derivatives Of ◽  
Anhydrous Acetic Acid

Heating 1-(2,3-di-O-benzoyl-β-D-arabinofuranosyl)-N4-benzoylcytosine (I) in 80% acetic acid afforded 1-(2,3-di-O-benzoyl-β-D-arabinofuranosyl)-N3-benzoylcytosine (II). Benzoylation of 5'-O-tritylcytidine (V) led to the 2',3',N4-tribenzoyl derivative VI which was refluxed with 80% acetic acid to give 2',3',N3-tribenzoylcytidine (VII). Analogously, 2',3',5',N4-tetrabenzoylcytidine (IX), prepared by benzoylation of cytidine with benzoyl cyanide, gave on reflux with 80% acetic acid 2',3',5',N3-tetrabenzoylcytidine (X). Under identical conditions, 1-methyl-N4-benzoylcytosine (XI) afforded directly 1-methyluracil (XII) .This migration takes place also in acetyl derivatives of cytosine nucleosides: 2',3',5',N4-tetraacetylcytidine (XIII) was transformed to the N3-acetylcytosine derivative XIV. On the other hand, migration of acetyl or benzoyl group from the exo-amino group of adenine has not been observed under the mentioned conditions. The migration of the N4-acyl group of cytosine derivatives proceeds best in aqueous acetic acid, more slowly also in anhydrous acetic acid, but not by action of trifluoroacetic acid in 1,2-dichloroethane.

THE DECARBOXYLATION OF ANTHRANILIC ACID

1952 ◽  
Vol 30 (7) ◽  
pp. 529-540 ◽  
Author(s):  
W. H. Stevens ◽  
J. M. Pepper ◽  
M. Lounsbury
Keyword(s):  
Carbon Dioxide ◽  
Melting Point ◽  
Isotope Effect ◽  
Anthranilic Acid ◽  
Electrophilic Substitution ◽  
Reaction Rate ◽  
Mineral Acid ◽  
Detailed Mechanism ◽  
Rate Determining Step ◽  
Acid Catalyzed

Anthranilic acid is known to decarboxylate on being heated above its melting point, or on being boiled in water. We have found that the aqueous decomposition can be acid catalyzed, but that, after the concentration of added mineral acid approximates that of the anthranilic acid, the reaction rate decreases with increasing mineral acid concentration. A mass spectrometer study of the carbon dioxide produced in the decomposition has shown that C12-carboxyl anthranilic acid decomposes at the same rate as C13-carboxyl anthranilic acid. Thus, unlike all other organic acid decarboxylations in which an "isotope effect" has been searched for thus far, the decarboxylation of anthranilic acid does not show an "isotope effect". From the experimental facts available, it appears that the mechanism of the decarboxylation is best explained as bimolecular electrophilic substitution, with the attack of a proton being the rate determining step. While other possibilities are not entirely excluded, a proton attack on the α carbon of the zwitterion is the detailed mechanism suggested as being most probable.

Sign in / Sign up

Export Citation Format

Share Document