Synthesis of l-methyl-3-methylthio- and 1-methyl-3-methylsulfinyl-4-substituted 2(1h)-quinolinones

摘要

Treatment of 4-substituted (X=C1,OCH_3,SCH_3) quinolinium salts (2) in aqueous-DMSO solution with K_3[Fe(CN)_6] / NaOH system led to the respective 2-quinolinones (3) (60-69 %) which were accompanied by 1-methyl-3-methylthio-4-quinolinone (8) (ca.20%).3-Methylthio substituent in quinolines (1),4-quinolinethione (5) and 2-quinolinones (3) underwent S-oxidation to a sulfinyl group when the compounds (1),(3) and (5) were treated with nitrating mixture (-5 deg C,1 mol.eqv.of HNO_3),but with an excess of nitric acid 2-quinolinones (3) were transformed to the respective 3-methylsulfinyl-6-nitro derivatives (7).The reaction of 4-chloroquinolines (la),(3a) (at 140-160 deg C) and (4a) (at 0 deg C) with dimethylamine gave high yield of the 4-dimethylamino derivatives (Id),(3d) and (4d),respectively.