An organic compound gives following spectral data: IR : 2210, $1724 \mathrm{cm}^{-1},{ }^{1} \mathrm{H} \mathrm{NMR}: \delta 1.4(\mathrm{t}, J=7.1 \mathrm{Hz}, 3 \mathrm{H}), 4.4(\mathrm{q}, J=7.1 \mathrm{Hz}, 2 \mathrm{H}) ; \quad{ }^{13} \mathrm{C} \mathrm{NMR}: \delta 16$, 62, 118, 119, 125, 127, 168. The compound is