Identification of 2-O (indole-3-acetyl)-D-glucopyranose, 4-O-(indole-3-acetyl)-D-glucopyranose and 6-O-(indole-3-acetyl)-D-glucopyranose from kernels of Zea mays by gas-liquid chromatography-mass spectrometry

New esters of indole-3-acetic acid and d-glucose have been isolated from mature sweet-corn kernels of Zea mays. The esters were resolved by t.l.c. into two fractions having R_F values distinct from that of authentic 1-O-(indole-3-acetyl)-β-d-glucopyranose. Analysis of the trimethylsilyl ethers of the two fractions by combined gas-liquid chromatography-mass spectrometry (g.l.c.-m.s.) showed that the esters have a free carbonyl group. Labeling of the carbonyl carbon atom with an O-methyloxime group, and analysis of the O-trimethylsilyl O-methyloxime derivatives by g.l.c.-m.s. permitted the new compounds to be identified as a mixture of 2-O-(indole-3-acetyl)-d-glucopyranose, 4-O-(indole-3-acetyl)-d-glucopyranose, and 6-O-(indole-3-acetyl)-d-glucopyranose.