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

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

Splicing-dependent NMD does not require the EJC in Schizosaccharomyces pombe

Nonsense-mediated mRNA decay (NMD) is a translation-linked process that destroys mRNAs with premature translation termination codons (PTCs). In mammalian cells, NMD is also linked to pre-mRNA splicing, usually PTCs trigger strong NMD only when positioned upstream of at least one intron. The exon junction complex (EJC) is believed to mediate the link between splicing and NMD in these systems. Here, we report that in Schizosaccharomyces pombe splicing also enhances NMD, but against the EJC model prediction, an intron stimulated NMD regardless of whether it is positioned upstream or downstream of the PTC and EJC components are not required. Still the effect of splicing seems to be direct—we have found that the important NMD determinant is the proximity of an intron to the PTC, not just the occurrence of splicing. On the basis of these results, we propose a new model to explain how splicing could affect NMD