Thesis-Final 03 June 2011 pdf - Jacobs University

Results and discussion Chapter 3
Figure 58: 13 C-NMR spectrum of bisacetonide, (49)
13 C-NMR shows nineteen signals as it was expected. Four methyl protons which are
characteristic for the acetonide moiety occurred at 25.36, 25.62, 28.64 and 28.84 ppm
and were assigned to C-10, C-11, C-12 and C-13. The signals of methylene carbons
were found at 35.08 and 37.38 ppm and assigned to C-6 and C-2 carbons. The other
three carbons of cyclohexane ring which has one proton attached to each, are found at
67.36, 71.79 and 76.78 ppm and assigned to C-5, C-3 and C-4 carbons on the basis of
chemical shift. Another peak was observed at 78.45 ppm and assigned to C-1 due to
electronegativity conciderations effect. The two carbons which belong to two acetal
groups were found at 109.08 and 111.57 ppm and assigned to C-8 and C-9 carbons.
The carbonyl carbon found at 176.21 ppm assigned as C-7. The IR spectrum of
bisacetonide also showed the typical peak at 1788 cm -1 as expected.
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