Collect. Czech. Chem. Commun. 1999, 64, 257-264

Synthesis of 2-Substituted-6,7-dimethoxy- and 6,7,8-Trimethoxy-3-hydroxyquinolin-4(1H)-ones

Pavel Hradila,*, Jan Vaněčekb, Jan Hlaváčc and Juraj Ševčíkd

a Farmak Co., 771 17 Olomouc, Czech Republic
b Research Institute of Organic Syntheses Ltd., 532 18 Pardubice-Rybitví, Czech Republic
c Department of Organic Chemistry, Palacký University, 771 46 Olomouc, Czech Republic
d Laboratory of Bioanalytical Research, Palacký University, 771 26 Olomouc, Czech Republic


Acetonyl and phenacyl esters of 4,5-dimethoxy- and 3,4,5-trimethoxyanthranilic acids 3 were prepared by reduction of corresponding nitro derivatives 2. Acetonyl 4,5-dimethoxyanthranilate (3a) was prepared by reaction of 4,5-dimethoxyanthranilic acid and chloroacetone. Cyclization of these acetonyl and phenacyl esters in polyphosphoric acid provided the corresponding 2-substituted-6,7-dimethoxy- and 6,7,8-trimethoxy-3-hydroxyquinolin-4(1H)-ones 4. A new method of the thermal cyclization is also described. The structure of the prepared compounds was confirmed by 1H NMR spectroscopy.

Keywords: Cyclization; Anthranilates; 3-Hydroxyquinolin-4(1H)-ones; Quinolinones.