How would the IR spectrum of your aldol condensation products have differed from
ID: 519840 • Letter: H
Question
How would the IR spectrum of your aldol condensation products have differed from that of your starting ketone? Provide at least one specific example (i.e. peak X would have moved to higher/lower frequency).
The first photo is of the reactant cyclopentanone.
The second photo is of the reactant 4-Methoxybenzaldehyde.
The third photo is of the product (2E,5E)-2,5-Bis(4-methoxybenzylidene)cyclopentanone.
This is a double aldol reaction and there are 2 equivalents of the aldehyde.
Spem an ne 50 3462 20 022 74 12 02 010 20 15 410 se 53 i 710 BB 2921 35 42 1020 74 502 3D 2004 26 1408 22 969 30 473 3G 2000 79 1313 60 g 74 483 47 1980 04 1278 49 891 Bi 457 1 1287 50 BCKExplanation / Answer
In IR spectra of cyclopentanone, the carbonyl group at 1700 cm-1, where as in product it will be in1680 cm-1 due to conjugated double bond
In IR spectra of 4-methoxy benzaldehyde carbonyl stretching frequency in 1700 cm-1, this will disappear in product and form new band around 1600 cm-1 is due to C=C
In proton NMR new peak at 7.2 ppm is due to ethelinc hydrogen and methoxy signal will be downfield due to extended pi conjugation