| dc.description.abstract | She thesis consists of two parts,
Part I
After introducing the importance of Wieland’s tricarboxylic acid
(obtained by the degradation of bile acids), in
the elucidation of their structures, the synthesis of the gross
structure of this acid has been described in this part.
In section 2 of this part, experiments on the
hydrolysis of ethyl 4?(1?carbethoxy?5?oxocyclopentyl)?2?pentenoate
and ethyl 4?(1?carbethoxy?5?oxocyclopentyl)?valerate to obtain the
normal hydrolysis products are described. It may be mentioned that
ethyl 4?(1?carbethoxy?5?oxocyclopentyl)?2?pentenoate serves as a
model compound in the projected synthesis of Wieland’s tricarboxylic
acid.
In section 2 of this part deals with the synthesis of the gross
structure of Wieland’s tricarboxylic acid. Methyl 2?methylcyclopentane?
1,2,3,4?tetracarboxylate, prepared from methyl 2?methyl?5?oxocyclo?
pentane?1,2,3?tricarboxylate, was condensed with ethyl 4?bromo?2?
pentenoate. Hydrolysis and decarboxylation of the tri?acid after
esterification was effected by the modified Wolff?Kishner
reduction and hydrogenation to yield the tri?methyl ester of Wieland’s
acid.
Cholic acid is expected to yield the lactone form of 2?methyl?
cyclopentane?1,2,3?tricarboxylic acid on degradation. The possibility
of using this evidence in providing an additional proof for the
??orientation of the side?chain of bile acids and sterols is
discussed. It is highly desirable that the different lactones of
2?methylcyclopentane?1,2,3?tricarboxylic acid should be synthesised
for use as reference compounds. With this in view, the syntheses of
two isomers of this acid are described in this part. Ethyl 3?acetyl?
2?methylcyclopentane?1,2,3?tricarboxylate, prepared from ethyl
2?methylcyclopentane?2,3?dicarboxylate, on catalytic hydrogenation and
hydrolysis yielded two acids. One of these was also prepared by the
oxidation of 7?methyl?bicycloheptane?1?one?2,3?dicarboxylic
acid obtained from ethyl 2?methylcyclopentane?2,3?dicarboxylate.
It has thus been possible to assign configurations for the two acids.
Attempts made towards the synthesis of 2?methylcyclopentane?1,2,3?
tricarboxylic acid from 2?methyl?5?acetoxyacetylcyclopentanone?carboxylic
acid and from the lactone of 2?methyl?1?hydroxyethyl?3?
carboxycyclopentanone have also been recorded. | |
