Question

Hi could you help me with this problem please?

The following spectroscopic data were obtained for an organic compound:
i. MS (relative abundance in parentheses): M⁺ = 86 ; signals at 29 (92) and 41 (100) among others
ii. IR (cm^-1): 3100 (weak sharp), 2970 (medium sharp), 2850 (medium), 1650 (weak sharp), 1100 (strong sharp)
iii. H¹ NMR :
    Signal A at 4 ppm (3H, triplet),
    Signal B at 3.53 ppm (2H quartet),
    Signal C at 4.01 ppm (2H, doublet),
    Signal D₁ at 5.25 ppm (1H, doublet)
    Signal D₂ at 5.28 ppm (1H, doublet)
    Signal E at 5.95 ppm (1H, multiplet)
    note: signal D₁ and D₂ are two separate signals, right next to each other, each with integration of 1H and multiplicity of "doublet"
iv. C13 NMR (proton \-decoupled):
    Signal I at 14 ppm,
    Signal II at 64 ppm,
    Signal III at 71 ppm,
    Signal IV at 115 ppm
    Signal V at 135 ppm.

Please answer the following:
A. Draw the most likely structure of this compound. Show all of the hydrogens in the structure.

B. Label all H's with the signal letter that the Hproduces in the H¹ NMR spectrum. Explain why each H¹ NMR signal has the chemical shift specified. Be specific about each group of chemically-equivalent protons in this particular compound (not in general)

C.Label all C's with the Roman numeral for the signal that the c produces in the C¹³ NMR spectrum. Explain why each C¹³ NMR signal has the chemical shift specified and just like with the H¹ NMR above, be specific

D. Identify the type of bond that gives each of the five IR absorbtion bands and explain why.

E. Explain multiplicities for EACH and EVERY H¹ NMR signal (i.e. what is each signal being split by?). Make sure to explain why there are actually two signals near 5.25 ppm (signals D₁ and D₂) that are both doublets, instead of a single signal that would be a doublet of doublets. Note: The hydrogens producing signals D₁ and D₂ are actually coupled to each other, but the coupling constant is so small that it is hard to see any coupling of D₁ with D₂ in the spectrum. The info for D₁ and D₂ above assume that J for these two protons is 0 Hz. Also assume that long-range coupling is not observed.

Answer 1

MS Page No. Date 24n0 g8S0 도 GSo C-O H H NMR 5,9 ane 135

Page No Date 2 X3 29 001 b NMR D 2