Hydrolysis of substituted 8-acetoxyquinolines.
In the absence of metal ions, the hydrolysis of 2-methyl-8-acetoxyquinoline and of 5-chloro-8-acetoxyquinoline follow the same reaction paths as those of the parent ester 8-acetoxyquinoline, including an intramolecular catalysis by the quinoline nitrogen. Unlike the hydrolysis of the other esters, that of the 2-methyl compound appears not to be catalysed by metal ions, and this is consistent with the view that catalysis by a metal ion involves the formation of a 7-membered chelate structure.
Neighboring Group Participation
Neighbouring-group participation in proton-transfer reactions is generally referred to as intramolecular general-acid or intramolecular general-base catalysis [1]. Two types are possible. The first involves an intramolecular proton transfer, either abstraction of a proton from a reacting functional group by an internal base or donation of a proton to one by an internal acid. The intramolecularly general-base catalysed enolization of the anion of 2-carboxy-acetophenone (see p. 370) and the intramolecularly general-acid catalysed hydrolysis of 2-methoxy-methoxybenzoic acid (see p. 342) are examples of reactions which are thought to involve processes of this type. In the second type the proton transfer is intermolecular with attack of a nucleophile on one functional group of a molecule being facilitated by proton abstraction by a second basic functional group. The intramolecularly general-base catalysed hydrolysis of the anion of phenyl salicylate (see p. 348) is a reaction which is thought to involve a process of this type.
Studies on the composition, quality and processing of triticale. Part II. Mineral composition of grain and flour.
Mineral composition of grain and flour in 14 promising triticale strains from India are reported. The mean values for whole grain, i.e. Ca (0.47 mg/g), P (2.70 mg/g), K 4.60 mg/g, Na (352 micrograms/g), Zn (41.6 micrograms/g), Cu (7.0 micrograms/g), Fe (73.4 micrograms/g) and Mn (33.6 micrograms/g) were obtained as compared to those of flour, i.e. Ca (0.27 mg/g), P (0.97 mg/g), K (1.64 mg/g), Na (231 micrograms/g), Zn (26 micrograms/g), Cu (4.0 micrograms/g) and Mn (10.5 micrograms/g), respectively. These values were found to be considerably higher than those of wheat. Highly significant positive correlations of ash with sodium and zinc in whole grain were observed. In the case of triticale flour, highly significant positive correlations of ash with manganese, phosphorus and potassium were obtained.