Arylamino methylenemalonate

Diethyl (arylamino)methylenemalonates (684) were cyclized with a 2 1 mixture of acetic anhydride and concentrated sulfuric acid at ambient temperature to give 4-hydroxyquinoline-3-carboxylates (685) in 15-80% yields (54JIC555, 54JIC711, 54JIC951). 

Quinolines have also been prepared on insoluble supports by cyclocondensation reactions and by intramolecular aromatic nucleophilic substitution (Table 15.26). Entry 10 in Table 15.26 is an example of a remarkable palladium-mediated cycloaddition of support-bound 2-iodoanilines to 1,4-dienes. Reduction of the nitro group of polystyrene-bound 2-nitro-l-(3-oxoalkyl)benzenes with SnCl2 (Entry 11, Table 15.26) leads to the formation of quinoline /Y-oxides. These intermediates can be reduced to the quinolines on solid phase by treatment with TiCl3. 4-Quinolones have been prepared by thermolysis of resin-bound 2-(arylamino)methylenemalonic esters [311]. 

The reaction of 2-aminothiazole and isopropylidene bis(methylthio)-methylenemalonate (459, R2 = R3 = SMe) or 1-methylthioalkylidenema-lonates (459, R2 = Me, Et, Ph R3 = SMe) in boiling ethanol for 2.5 hr or in dimethylformamide at 120-130°C for 4-5 hr, gave 2-substituted 5-oxo-5//-thiazolo[3,2-a]pyrimidine-6-carboxylates (462) in good yields (89S-317). Similarly, in boiling ethanol, 2-substituted 4-oxo-4//-pyrido[l,2-a]-pyrimidine-3-carboxylic acids (463) were obtained in 80-85% yields. When anilines were reacted with isopropylidene bis(methylthio)methy-lenemalonate (459, R2 = R3 = MeS), (methylthio)(arylamino)methylene-malonates (464) were obtained 61-88% yields. 

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