Piperidine → HCID 45089600, compound

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Reaction Steps

For example, 2,4-diaminobenzaldehyde 57.7 (Apin Chemicals) is reacted with one molar equivalent of methyl pyruvate 57.2 in methanol, in the presence of a base such as piperidine, to afford methyl-7-aminoquinoline-2-carboxylate 57.8. Basic hydrolysis of the product, employing one molar equivalent of lithium hydroxide in aqueous methanol, then yields the carboxylic acid 57.9. The amino-substituted carboxylic acid is then converted into the diazonium tetrafluoborate 57.10 by reaction with sodium nitrite and tetrafluoboric acid. The diazonium salt is heated in aqueous solution to afford the 7-hydroxyquinoline-2-carboxylic acid, 57.11, Z=OH. Alternatively, the diazonium tetrafluoborate is heated in aqueous organic solution with one molar equivalent of cuprous bromide and lithium bromide, to afford 7-bromoquinoline-2-carboxylic acid 57.11, Z=Br. Alternatively, the diazonium tetrafluoborate 57.10 is reacted in acetonitrile solution with the sulfhydryl form of an ion exchange resin, as described in Sulfur Lett., 2000, 24, 123, to prepare 7-mercaptoquinoline-2-carboxylic acid 57.11, Z=SH.

Provenance & Evidence