Applications Example 1
The spectra shown in Figure 1 (a)−(d)were obtained for a compound of composi-
tion C 67.0%, H 7.3%, N 7.8%; melting at 135°C.
(i) Empirical formula: C 10 H 13 NO 2 ; RMM = 179(ii) DBE = 5(iii) 1a: IR (KBr disk)
3300 cm−^1 H-N- stretch
3000+ H-C- aromatic stretch
3000 H-C- aliphatic
1670 C=O stretch (amide or aromatic links?)
1650, 1510, etc. aromatic ring vibrations
This suggests a substituted aromatic amide.(iv) UV (methanol solution): major peaks at 243 and 280 nm also suggest an
aromatic compound(v) 1b: MS (EI)
m/z
179 M+•Must be odd number of nitrogens
137 M- 42: loss of CH 2 CO; CH 3 CO- compound?
43 CH 3 CO+
27 and 29 C 2 H 3 +and C 2 H 5 +
108/109 (HO−C 6 H 4 −NH 2 )+and less 1 H(vi) 1c: 1-H NMR(80 MHz, CCl 4 solution)
d/ppm Relative integral Multiplicity Assignment
1.3 3 3 CH 3 −CH 2 −
2.1 3 1 CH 3 −CO−
4.0 2 4 O−CH 2 −CH 3
6.8, 7.3 4 ∼2 doublets 1,4−ArH−
7.6 1 1, broad Ar−NH−CO1d: 13-C NMR(20.15 MHz, CDCl 3 solution)
d/ppm Multiplicity Assignment
14.8 4 CH 3 –CH 2 -
24.2 4 CH 3 −CO-
63.7 3 O−CH 2 −CH 3
114.7 2 ArCH−
122.0 2 ArCH
131.0 1 ArC−CO−
155.8 1 ArC−N−
168.5 1 Ar−CO−(vii) The pair of doublets in the proton NMR suggests a 1,4-disubstituted
aromatic compound. Evidence for an ethylgroup and for an amide
suggest the structure C 2 H 5 O−C 6 H 4 –NHCOCH 3 , 4-ethoxyacetanilide
(phenacetin).288 Section F – Combined techniques