Survey of Solvents for the Conrad–Limpach Synthesis of 4-Hydroxyquinolones

Abstract

A study of the synthesis of a 4-hydroxyquinoline derivative using the Conrad–Limpach reaction led to the identification of inexpensive and user-friendly solvents for this thermal condensation.

Keywords:

• Conrad–Limpach
• 4-hydroxyquinoline
• thermal condensation

Notes

^a A, methyl benzoate; B, ethyl benzoate; C, propyl benzoate; D, isobutyl benzoate; E, 2-nitrotoluene; F, 1,4-butanediol; G, tetrahydronaphthalene; H, decahydronaphthalene; I, 1,2,4-trichlorobenzene; J, Dowtherm A; K, 2,6-di-tert-butylphenol.

^b Obtained from Lange's Handbook, 14th edition.

^c Obtained from Aldrich catalog, 2007–2008 edition.

^d Reaction with 1,4-butanediol did not produce any product.

^e Reaction with decahydronaphthalene yielded only noncyclized enamine product.