NMR Spectroscopy

Problem #4: C₆H₁₀O₃

The molecule contains an oxygen, and from the analysis, contains two double bonds, carbonyls or rings.
The mass spectrum displays a molecular ion and the base peak represents the formation of the acylium ion, indicating the presence of a methyl adjacent to a carbonyl. The presence of an m-45 peak strongly suggests the presence of an ethoxy group.
The ¹³C spectrum contains six peaks, indicating that all carbons are unique. The quartets at d 14 and 24 represent relatively simple methyl groups; the triplets at d 59 and 47 represent a CH₂ groups bonded to mildly electronegative groups; the singlets at d 207 and 172 are in the carbonyl region, and most likely a ketone or aldehyde (d 207) and an ester (d 172).
The proton NMR shows evidence for an ethyl group and isolated CH₂ and CH₃ groups. The methylene of the ethyl group must be next to an electronegative atom (most likely oxygen) suggesting an -OCH₂CH₃ group. The isolated CH₂ must also be flanked by mildly electronegative groups, and the isolated CH₃ is in the region often observed for methyls adjacent to carbonyls.
The IR is consistent with a simple saturated hydrocarbon, possibly containing two carbonyls (based on the side peak at 1670 cm^-1). The minor peak at 3400 cm^-1 is too small to be an -OH.
The simplest structure which is consistent with all of these data would be a dicarbonyl compound containing an ethoxy residue and a methyl ketone (based on the presence of the acylium ion in the MS).