Question

C. HNMR-6 points The eucalyptus oil mig Below are HNMR and CNMR spectra of gne of the possible erpere ht have been analyzed by HNMR to determine which diene it comalned of the possible l This may not be the terpene starting materials: β- myreene, a-terpinene, allo-ocimene or a-phell actually present. andrene (Table 1). This may ON the spectra that follow: a. Label all terminal methyl groups b. Label all alkene Proons intheHNMR with (:01) 1pt e. Label all alkene Carbons in the CNMR with (C) ipt all erminal methyl groups in the INMR with ( CH3) 1p HNMR peaks ppm int 5.62 IH 5.62 H d 5.58 d 2.28 Hm 2.09 4H m 1.77 3H s 1.77 1.02 6H d

Answer 1

Interpretation of spectrum

Compound : alpha-terpinene

1H NMR

1.02 ppm (doublet, 6H) for two CH3's next to CH

1.77 ppm (singlet, 3H) for CH3 next to quaternary alkene carbon

2.09 pm (multiplet, 4H) for CH2's next to each other

5.58 ppm and 5.62 ppm for alkene protons

13C NMR

118-145 ppm four peaks for alkene carbons

rest all peaks between 20-36 ppm are for aliphatic carbons

alpha-terpinene