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Chapter – 5 Synthesis and Characterization…..
most identifiable and characteristic peak for these types of compounds
from which it could be prove that the compounds were the C-Mannich
bases and were not the N-Mannich bases.
2. Two protons of methylene group attached at C3 position of coumarin
nucleus gave a sharp singlet in the up-field at 3.76 δ ppm.
3. Three most shielded protons of methyl group of ethyl piperazine ring
gave triplet at 1.12 δ ppm.
4. Two protons of methylene group attached on nitrogen atom in
piperazine ring and eight protons of piperazine ring merged in the
region of 2.15-2.62 δ ppm .
5. Four protons of coumarinyl phenyl ring and four protons of another
phenyl ring attached to the secondary nitrogen gave multiplet peaks in
the region of 7.00-7.48 δ ppm.
6. J values were calculated which were in the agreement of the m
substitution.
13
C NMR (APT 25) spectral interpretation of 3-[(4-ethylpiperazin-1-yl)
methyl]-4-{[3-(trifluoromethyl) phenyl] amino}-2H-chromen-2-one (DNJ-
1013)
In 13 C NMR (APT 25), upward directed peaks were due to C and CH2
while downward directed peaks were due to CH and CH3.
1. Carbonyl group of β keto ester showed upward peak at 162.89 δ ppm.
2. Coumarinyl C4 carbon showed upward directed peak at 143.29 δ ppm
chemical shift value.
3. 132.89 δ ppm chemical shift is due to trifluoromethyl group.
4. C3 carbon of coumarin nucleus showed peak upward at 105.57 δ ppm
from which it could be prove that the compounds were the C-Mannich
bases and were not the N-Mannich bases because if the compounds
would be N-Mannich bases, they would show peak of C3 carbon
downward due to CH.
5. Peaks at 77.03-77.88 δ ppm are due to the solvent CDCl3.
Department of Chemistry, Saurashtra University, Rajkot – 360 005 302