Conrad-Limpach Cyclization

M. Conrad, L. Limpach, Ber. 20, 944 (1887); 24, 2990 (1891).

Thermal condensation of arylamines with β-ketoesters followed by cyclization of the intermediate Schiff bases to 4-hydroxyquinolines:

R. H. Manske, Chem. Rev. 30, 121 (1942); R. H. Reitsema, ibid. 43, 47 (1948); H. Henecka, Chemie der Beta Dicarbonylverbindungen (Berlin, 1950) p 307; R. C. Elderfield, Heterocyclic Compounds 4, 30 (1952); J.-C. Perche, G. Saint-Ruf, J. Heterocyclic Chem. 11, 93 (1974); J. M. Barker et al., J. Chem. Res. (S) 1980, 4; J. A. Moore, T. D. Mitchell, J. Polym. Chem. 18, 3029 (1980). Cf. Combes Quinoline Synthesis; Doebner Reaction.