Structural Characterization of Isomeric Methyl 2-(2-Oxo-3-indolyl)acetate and Methyl 1-(2-Oxo-4-quinolyl)formate

Crystalline and amorphous forms of methyl 2-(2-oxo-3-indolyl)acetate (1) were obtained showing significant differences in their melting points.The X-ray structure for the trigonal polymorph is reported.In addition, oxindole (1) was easily acid-catalyzed ring enlarged to give the structural isomer quinolone (2) for which the crystal structure was also determined.These results resolve several chemical inquiries related to the structural characterization of 1 and 2.