Synthesis of 5H-dibenzo[a,d]cycloheptene-5-carboxylic acid and related compounds. 1,5-Hydride transfer to inductively destabilized carbonium ions

1968 ◽  
Vol 46 (23) ◽  
pp. 3665-3670 ◽  
Author(s):  
D. E. Horning ◽  
J. M. Muchowski
Keyword(s):  
Carboxylic Acid ◽  
Carbonyl Group ◽  
Isotope Effect ◽  
Hydride Transfer ◽  
Large Magnitude ◽  
Carbonium Ion ◽  
Carbonium Ions ◽  
Acid Catalyzed ◽  
Derivatives Of ◽  
Related Compounds

The synthesis of 10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-carboxylic acid (2) and several derivatives of 5H-dibenzo[a,d]cycloheptene-5-carboxylic acid (1; a–c) from 5-hydroxy-10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-carboxylic acid and derivatives thereof (3; a–c) is described.The p-toluenesulfonic acid-catalyzed elimination of water (at 110.6° in toluene) from the deuterated hydroxy ester (3b; C-10, 11 d2) resulted in the incorporation of deuterium at C-5 of the olefinic ester 1b with a KH/KD of 2.76. The large magnitude of this isotope effect indicated that the reaction proceeded via a rate-determining transannular 1,5-hydride transfer from one of the benzylic positions of 3b to the carbonium ion generated alpha to the methoxy-carbonyl group.

Isocarbostyrils. II. The Conversion of 2-Methyl-4-acyl-5-nitroisocarbostyrils to 2-Substituted Indole-4-carboxylic Acids

1971 ◽  
Vol 49 (17) ◽  
pp. 2797-2802 ◽  
Author(s):  
D. E. Horning ◽  
G. Lacasse ◽  
J. M. Muchowski
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Alkaline Hydrolysis ◽  
Mannich Reaction ◽  
Reductive Cyclization ◽  
Acid Catalyzed ◽  
Acid Anhydrides ◽  
Hydrolysis Of ◽  
Derivatives Of

The sulfuric acid catalyzed acylation of 2-methyl-5-nitroisocarbostyril with carboxylic acid anhydrides gave the corresponding 4-acylated derivatives 3, which underwent reductive cyclization to 2-substituted derivatives of 4-methyl-1,3,4,5-tetrahydropyrrolo[4.3.2.de]isoquinolin-5-one (4). Alkaline hydrolysis of the six-membered lactam in 4 was accompanied by a retro-Mannich reaction to produce 2-substituted indole-4-carboxylic acids in about 40 % overall yield from 3.

scholarly journals THE STEREOCHEMISTRY OF HALOGEN DISPLACEMENT BY NITRATE ION RACEMIZATION AND RETENTION OF CONFIGURATION IN THE SYNTHESIS OF DINITRATE ESTERS

1965 ◽  
Vol 43 (6) ◽  
pp. 1656-1660 ◽  
Author(s):  
L. D. Hayward ◽  
M. Jackson ◽  
I. G. Csizmadia
Keyword(s):  
Silver Nitrate ◽  
Steric Effect ◽  
Heterogeneous Reaction ◽  
Ion Pair ◽  
Alkyl Halides ◽  
Preferential Formation ◽  
Carbonium Ion ◽  
Carbonium Ions ◽  
And Inversion ◽  
Derivatives Of

The reaction of silver nitrate in dry acetonitrile with 2,5-dideoxy-2,5-diiodo-1,4;3,6-dianhydro-L-iditol resulted in formation of the dinitrate esters of the 1,4;3,6-dianhydrides of D-mannitol, D-glucitol, and L-iditol. Similarly both endo- and exo-nitrato groups were introduced in displacement of the endo-halogen in the 2-deoxy-2-iodo-5-O-acetyl and 2-deoxy-2-iodo-5-O-p-toluenesulfonyl derivatives of 1,4;3,6-dianhydro-L-iditol. Since both types of nitrato groups were stable to silver nitrate, the racemization occurred during the displacement and was attributed to formation of cyclic carbonium ion intermediates. The steric effect of the adjacent ring in the carbonium ions apparently suppressed the termolecular, ion-pair mechanism previously established for the metathesis of acyclic alkyl halides and caused preferential formation of the exo-nitrato derivatives.The heterogeneous reaction of meso-dibromostilbene with silver nitrate in acetic acid or acetonitrile gave meso-dihydrobenzoin dinitrate with overall retention of configuration. This result could be most readily reconciled with the contrasting sequence of retention and inversion previously reported for meso- and dl-2,3-dibromobutane if participation of neighboring phenyl groups occurred in the second displacement step.

The hydrolysis of some N-benzoylamino acids in dilute mineral acid

1967 ◽  
Vol 45 (17) ◽  
pp. 1921-1924 ◽  
Author(s):  
J. B. Capindale ◽  
H. S. Fan
Keyword(s):  
Carboxylic Acid ◽  
Hydrochloric Acid ◽  
Glutamic Acid ◽  
Rate Constants ◽  
Mineral Acid ◽  
Dilute Solution ◽  
Acid Catalyzed ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Derivatives Of

The behavior of N-benzoylaspartic acid and N-benzoylglutamic acid has been investigated at 100° in dilute solution in water and aqueous hydrochloric acid within the pH range 3.1–0.5. Some data are presented concerning the hydrolysis of the N-benzoyl derivatives of alanine, β-alanine, leucine, glycine, serine, and β-ethanolamine in water, 0.1 N hydrochloric acid, and 2 N hydrochloric acid. Benzoylglutamic acid undergoes a pH-independent conversion into pyrrolid-2-one-5-carboxylic acid, which then hydrolyses in mineral acid to glutamic acid; however, N-benzoylaspartic acid, under similar conditions, hydrolyses much more rapidly by a route which does not involve the corresponding lactam as an intermediate. In anhydrous alcohols the solvolysis of N-benzoylaspartic acid gives mixtures of aspartic acid and the β ester.First-order rate constants have been obtained for the acid-catalyzed hydrolysis of pyrrolid-2-one-5-carboxylic acid (I) and azetidin-2-one-4-carboxylic acid (II) in water over this pH range.

scholarly journals HYDRIDE TRANSFER TO CARBONIUM IONS: I. THE MECHANISM OF THE REDUCTION OF TRIPHENYLMETHYL CARBONIUM ION IN FORMIC ACID

1957 ◽  
Vol 35 (8) ◽  
pp. 766-777 ◽  
Author(s):  
Ross Stewart
Keyword(s):  
Formic Acid ◽  
Kinetic Isotope Effect ◽  
Hydride Transfer ◽  
Resonance Spectroscopy ◽  
Hydride Ion ◽  
Carbonium Ion ◽  
Kinetic Isotope ◽  
Carbonium Ions ◽  
Entropy Of Activation ◽  
Rate Controlling Step

In an attempt to prove that reduction can take place by hydride transfer, the conversion of triphenyl carbinol in formic acid to triphenylmethane via the carbonium ion was examined. Kinetic and isotopic proof was obtained for the following mechanism:[Formula: see text][Formula: see text]The rate law based on the above mechanism is[Formula: see text]where R = C6H5, which leads to the integrated rate expression[Formula: see text]This equation was found to be obeyed under a variety of conditions.Anhydrous formic-d acid was synthesized in good yield by the glycerol catalyzed decomposition of oxalic acid-d2. The concentration of deuterium was shown by nuclear magnetic resonance spectroscopy to be greater than 99%. Use of this material in the reduction gave a kinetic isotope effect and led to isolation of triphenylmethane which had greater than 97% deuterium in the α-position, thus supporting the idea that a hydride ion was transferred from formate ion to the carbonium ion.The energy and entropy of activation for the rate controlling step have been found to be 18.3 kcal. per mole and −7.5 e.u. The negative ΔS‡ is presumably due to the less likely orientation for the transition state A as compared to B.[Formula: see text]

Isobutane from acid-catalyzed dehydration of butanols

1970 ◽  
Vol 48 (22) ◽  
pp. 3545-3548 ◽  
Author(s):  
John Warkentin ◽  
Kenneth E. Hine
Keyword(s):  
Acid Solution ◽  
Hydride Transfer ◽  
Strong Acid ◽  
Isomeric Butanols ◽  
Carbonium Ions ◽  
Acid Catalyzed

Dehydration of the four isomeric butanols by strong acid at about 160° gives a C4-fraction containing isobutane as well as the isomeric butenes. Isobutane probably arises by hydride transfer, from one or more donors including the substrate alcohol and hydrocarbons formed from it in the medium, to one or more carbonium ions including the t-butyl cation. Materials which react with 2,4-dinitrophenylhydrazine reagent to form 2,4-dinitrophenylhydrazones can be swept out of the hot acid solution with a stream of nitrogen.

Cyclization and acid-catalyzed hydrolysis of O-benzoylbenzamidoximes

1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský
Keyword(s):  
Reaction Rate ◽  
Kinetic Isotope ◽  
Acid Base Equilibrium ◽  
Mineral Acids ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Ph Scale ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media. It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1% solutions of mineral acids. Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed. From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid. The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.

scholarly journals Novel Derivatives of 4-Methyl-1,2,3-Thiadiazole-5-Carboxylic Acid Hydrazide: Synthesis, Lipophilicity, and In Vitro Antimicrobial Activity Screening

2021 ◽  
Vol 11 (3) ◽  
pp. 1180
Author(s):  
Kinga Paruch ◽  
Łukasz Popiołek ◽  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Malm ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Carboxylic Acid ◽  
Bacterial Infections ◽  
Acid Hydrazide ◽  
Antimicrobial Effect ◽  
In Vitro Antimicrobial Activity ◽  
Research Goal ◽  
New Compounds ◽  
Derivatives Of

Bacterial infections, especially those caused by strains resistant to commonly used antibiotics and chemotherapeutics, are still a current threat to public health. Therefore, the search for new molecules with potential antimicrobial activity is an important research goal. In this article, we present the synthesis and evaluation of the in vitro antimicrobial activity of a series of 15 new derivatives of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid. The potential antimicrobial effect of the new compounds was observed mainly against Gram-positive bacteria. Compound 15, with the 5-nitro-2-furoyl moiety, showed the highest bioactivity: minimum inhibitory concentration (MIC) = 1.95–15.62 µg/mL and minimum bactericidal concentration (MBC)/MIC = 1–4 µg/mL.

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