Reactions of some carboxylic acid derivatives.
thesisposted on 19.11.2015, 08:46 by William Vincent. Raftery
Aromatic esters of 4-hydroxybutyric and 5-hydroxyvaleric acids have been synthesised for the first time and their hydrolysis studied in the presence of a variety of catalysts. Generally the rates were greatly increased over those for the analogous non-hydroxy-substituted esters. The hydrolysis of phenyl 4-hydroxybutyrate is catalysed by hydroxide ions at pH's greater than 3.6 and by hydronium ions at pH's less than 3.6, there being no observable spontaneous hydrolysis. Catalysis by phosphate, acetate and imidazole was also observed. The first two of these probably act as general base catalysts but imidazole is probably a nucleophilic catalyst. The hydrolysis in moderately concentrated perchloric acid yielded data from which Hammett and Bunnett plots were constructed. The factors influencing the rates of ring closure for 5 and 6-rings have been analysed. An alternative explanation has been suggested to explain the inversion of configuration that occurs in the rearrangement of 4 and 5-alkoxyacyl chlorides to the alkyl 4 and 5-chioro-esters, respectively. The first example of alkoxy-cleavage in the rearrangement of a 4-alkoxyacyl chloride is reported. A novel synthesis of 2-cyanobenzoic acid is reported. Evidence for the existence of an unsubstituted isoimide was shown using infrared spectroscopy. No intermediate was detected in the acid catalysed hydrolysis of 2-cyanobenzoic acid to phthalamic acid. The intermediacy of phthalimide in this reaction was eliminated. Attempts to study a novel type of catalysis by boric acid were thwarted by the failure to prepare esters of myo-inositol- 2-carboxylic acid. The preparation and hydrolysis of 4-hydroxybutyronitrile were attempted.