Frequencies 
(cm−1)
(N-H)st
(C-H)st ar
(O-H)st
(C=O)st
(C=N)st
(C=C)st
(N-H)δ
(O-H)δ
(C-O)st
(C-N)st
Compound 1
3257
2934
2817
-
-
-
1593
1567
-
-
1116
Compound 2
3278
2927
-
1647
-
1593
1568
-
-
-
Compound 3
-
3060
2788
-
1633
1577
-
1282
1207
-