Question

C NMR data provided when possible, show part Determine the structure of CHO from the IR, NR and structures that correspond to individual NMR resonances 1800 1600 2000 1400 1200 1000 000 3600 3400 3200 3000 2800 2600 2400 2200 1.10 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 normal decoupled 18C DEPT-135: (+) indicates positive peak (-) indicates negative peak indicates no peak DEPT-90 peaks indicated by Proposed Structure 200 180 160 140 120 100 80 60 40 20

Answer 1

I have marked H-atom as a,b,c,d for better understanding of equivalent H-atoms

Please Note: there is a printing mistake in DEPT-135. There has to be one CH_{​​​​​2} carbon. Which is at 33.4 ppmproposed structure is

x = heteroatom except OLS C6H2O 26+2 No. of unsaturation - +N-H-X. 2 +0 -12 -0 2x6 +2 1 IR • peak around 2900 cm-l indicates C(SP3)-H stretching peace around 1700 cm indicates c=2 stretching TH NMR • peak N26ppm sagt attached to the carbonyl carbon. peak 2.5pm is also attached to carbonyl carbon. 13c & DEPT • From Bc value & DEPT-135 peak at ~215pm indicates carbon Carbon (quaternary) • DEPT-go shows there is only on CH carbon at N40 ppm PT-125 shows rest 4 carbou are cida but y NMR shows there has to be one ctg proton. Hence there is 3-CH? carbon & one CH2 carbon. • DEPT-135 shows.

o CH3 He CH - CH 1.0 (t, 3H) ~ 2.51 (m, 1H). 13 -2.68(2,26) N11(d, 6H)