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alpha ‐phenylpropionic acid derivatives. Synthesis and dethiation of 5‐benzoylbenzo[ b ]thiophene‐3‐carboxylic acid
Author(s) -
Hannoun Mohammad,
Kolbah Dragutin,
Blaževié Nikola,
Mihalić Mladen,
Kajfež Franjo
Publication year - 1982
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570190529
Subject(s) - chemistry , oxalyl chloride , decarboxylation , raney nickel , chloroacetic acid , dicarboxylic acid , halogenation , derivative (finance) , alkylation , carboxylic acid , benzoyl chloride , hydrolysis , chloride , organic chemistry , thiophene , medicinal chemistry , acylation , catalysis , financial economics , economics
The total synthesis of the title compound 8 started with p ‐thiocresol which was acylated with oxalyl chloride to give compound 1 . This product underwent a condensation reaction with chloroacetic acid under basic conditions yielding compound 2 . Two different synthetic pathways were used to convert compound 2 into the title compound 8 . The first consisted in decarboxylation of 2 to 3 , which was then converted to the ester 4 , which was brominated and the product 5 was subjected to a Friedel‐Craft's reaction with benzene. The resulting benzyl derivative 6 was oxidized to the benzoyl stage i.e . compound 7 , which was finally hydrolyzed to 8 . The second pathway was similar to the first one so that the steps of esterification, bromination, Friedel‐Craft's alkylation and oxidation started with the dicarboxylic acid 2 . Thus compounds 12–16 were obtained, and the last product was decarboxylated to 8 . The yields in both procedures were similar. Finally, the dethiation of compound 8 with Raney nickel afforded compounds 18, 19 and 20 .