1. CH 9-2: HD/IR Example (step-by-step)
An unknown organic compound has a formula of C4H6O.
(1) What is the Hydrogen Deficiency? HD = _____ 4
(2) What functional groups might be present as suggested by the HD and formula?

2. (3) What functional group information can we get from the IR spectrum:
1712 cm-1
carbonyl
IR spectrum = ______________

3. (4) Now we can refine our original ideas for the type(s) of functional group(s) present, based on:
formula = C4H6O HD = carbonyl group
Carbonyl and alkene
Carbonyl and ring

4. (5) More Info: There is one 1o carbon and no 2o or 3o carbons
(5) More Info: There is one 1o carbon and no 2o or 3o carbons. Suggest one or more reasonable structures:
Note that based on this information, no rings are possible as they would have 2o & 3o carbon atoms.