Hydrolysis of Phenyl Furyl Ketimine - The Relative Negativity Effect

Phenyl furyl ketimine hydrochloride has been prepared and the velocity of its hydrolysis to the corresponding ketone measured. The velocity constant has been found to be of the order of l0xl0-3 measured at 25°C. The constant for diphenyl ketimine hydrochloride is 5.5x103measured at 0° or about 50x10-3 when calculated to 25 °. In view of the generally considered more highly negative character of the furyl radical over the phenyl, this result is in line with an observed rule that the ketimine salts are more resistant to hydrolysis the more negative the radicals attached to the carbimino group. The hydrolytic velocities of these and other ketimines already studied are compared on the basis of Kharasch\u27s table of relative negativities of aromatic radicals

A Study of the Hoesch-Houben Synthesis in the Preparation of Aromatic Ketimines and Hydroxy-Phenyl Iminoesters

This synthesis involves the condensation of a phenol with a nitrile (aliphatic or aromatic). It is effected by the passage of dry hydrogen chloride through their solution in anhydrous ether, with or without the addition of dry zinc chloride. Anhydrous aluminum chloride was substituted for zinc chloride in some cases

The Preparation and Properties of Furyl Phenyl Ketimine

This ketimine has been prepared through the condensation of furonitrile with magnesium phenyl bromide, followed by treatment with ice and ammonium chloride at about -15 degrees C. The hydrochloride, a white solid, is rather quickly hydrolyzed to the corresponding ketone, benzoyl furane. The velocity of this hydrolysis and the basic strength of the free ketimine base are determined

Effects of Hydrogen Ion Concentration upon the Hydrolysis Rates of Ketimines (Abstract)

Measurements have been made upon the hydrolysis rates of ketimine hydrochlorides to obtain information concerning the relation between their varied structures and stability toward hydrolysis1. The hydrogen ion concentration might appear as a catalytic factor in this hydrolysis2. It would thus seem necessary to determine these hydrolysis rates at the same hydrogen ion concentration if this factor has a marked effect. Different ketimine hydrochlorides alone in water produce, in the dilute solutions usually employed, pH values ranging initially from about a.6 to 5.3 and increasing in each case toward the pH of the equivalent ammonium chloride formed as the result of hydrolysis. Certain measurements on the hydrolysis rates of ketimine hydrochlorides of widely different initial pH values in water, to which an equivalent of hydrochloric acid was added, showed that their speed was actually lowered by this hydrogen ion increase although not enough to affect the general order of the rate

Preparation and Stability of Diphenyl Amine Hydronitrate

In connection with certain proposed studies the question of the preparation of diphenyl amine hydronitrate, or diphenyl ammonium nitrate, arose. A search of the literature revealed no record of this substance. The nearest equivalent reported was the perchlorate salt of diphenyl amine (Ber. 43, 1085-86. 1910). This compound was obtained upon treatment of a carbon tetrachloride solution of the amine with 70% perchloric acid added dropwise

The Strengths of Phenolic Ketimines and Their Methyl Ethers as Bases

The ionization constants of the monohydroxy-diphenyl ketimines and their methyl ethers are calculated from measurements of the hydrogen ion concentration of aqueous solutions of their hydrochlorides through the use of the quinhydrone electrode. This data has been collected as a part of the information expected to throw light on the varied stability toward hydrolysis shown by different ketimines

The Synthesis of 4-Hydroxy and 2-Hydroxy-Diphenyl Ketimines

These syntheses were carried out through the action of the corresponding hydroxy-nitrile upon magnesium phenyl bromide in an anhydrous ether medium. Over two equivalents of the Grignard reagent were employed, one to react with the phenol group and the other with the nitrile. The addition compound was decomposed with water and ammonium chloride at about -15 degrees C. The ketimine extracted with ether was precipitated as the hydrochloride by the addition of dry hydrogen chloride. The hydroxynitriles were prepared from the corresponding hydroxy-aldehydes by the action of acetic anhydride on their oximes. Some modifications were worked out in the preparation of the oximes and the nitriles

Hydrolysis Velocity of Ketimines - Steric Hindrance Effect

Additional work has been carried on to gain further information concerning the significance of ortho-substituted groups upon the rate of which diphenyl ketimine hydrochlorides hydrolyze to ketones. In this particular study the following isomeric ketimines have been prepared and their hydrolysis velocities determined: 2, 6-dimethyl-, 2, 5-dimethyl-, 2, 4-dimethyl-, and 3, 5-dimethyldiphenyl ketimines hydrochlorides. The first of these with the two ortho-substituted methyl groups is hydrolyzed appreciably only after prolonged boiling with water. The last with no ortho-substituent is hydrolyzed very rapidly at room temperature, so that its reaction velocity must be measured at 0°C. The second and third ketimine salts, each having one ortho-substituted methyl, are hydrolyzed at a moderate rate at 25°

Absorption Spectra of Ketimines with Reference to Ketimine-Enamine Tautomerism

The first reported preparation (Roesch, 1915, 1917) of diphenyl ketimine salts in which hydroxy groups were 2- and 4- positions indicated that these compounds were unusually stable toward hydrolysis to the corresponding ketones and ammonium chloride. Subsequent studies (Culbertson, 1927, 1931) have suggested that the resistance of these phenolic ketimine salts toward hydrolysis was due to a ketimine-enamine tautomerism, or resonance, resulting in masking the ordinary reactivity of the imine (\u3e N-H) group toward reaction with water