Synthesis and substitution reactions of some 3-substitution pyrroles

Huang, Chaog-wei (1967) Synthesis and substitution reactions of some 3-substitution pyrroles. Masters thesis, Memorial University of Newfoundland.

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Abstract

Product orientation and distribution in the Friedel-Crafts reaction and (or) Bromination of some 2- and 3-monosubstituted pyrrole derivatives have been studied. -- It was found that the acetylation of methyl 2-pyrrolecarboxylate with acetic anhydride in the presence of excess aluminum chloride not only increased the yield, but also had the advantage of separating the reaction products. -- Acetylations of 2-pyrrolecarbonitrile and 2-pyrrolecarboxaldehyde were found to give exclusively 4-substitution, while the 5-isomer was undoubtedly formed in minor amounts in the acetylation of methyl 2-pyrrolecarboxylate. The l;-acetylated acid obtained from the hydrolysis or oxidation of the corresponding acetylated products was converted to the known 3-acetylpyrrole. -- 5-Bromo and 5J-isqpropyl derivatives were the sole products isolated from the bromination and Friedel-Crafts isopropylation of methyl 3-pyrrolecarboxylate and 3-acetylpyrrole. -- The structures of the products were confirmed primarily through nuclear magnetic resonance evidence. Further identification was accomplished by a study of some chemical inter conversions. -- The reaction of pyrrylmagnesium bromide with methyl chloroformate was carried out and several new products isolated and identified. The synthesis of 3-isopropylpyrrole via the ring closure of a glycidic ester was also attempted.

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