Chapter SRP, Problem 32P

Compound X $\left({\text{C}}_{\text{7}}{\text{H}}_{\text{12}}{\text{O}}_{\text{4}}\right)$ is insoluble in aqueous sodium bicarbonate. The IR spectrum of X has a strong absorption peak near 1740 cm^−-1, and its broadband proton-decoupled 13C spectrum is given in Fig. 4. Propose a structure for X.

Figure 4 Broadband proton-decoupled ${}^{13}\text{C NMR}$ spectrum of compound X, Problem32. Information from the DEPT ${}^{13}\text{C NMR}$ spectra is given above each peak.