Question

Please help me interpret the proton NMR of this unknown aldehyde.

ZACH RIA A3 2 -1400 -1300 -1200 -1100 1000 -900 -800 -700 -600 -500 400 300 -200 -100 -100 -5.5 4.5 -5.0 -3.5 -4.0 -2.5 -3.0 -1.5 -2.0 -0.5 -1.0 f1 (ppm) 0.5 0.0 1.5 1.0 2,5 2.0 4.0 3.5 3.0 Adtyd SE 910- 660-h ar

Answer 1

The image of the given NMR data is as follows: PACH RIAA3 1400 1300 1200 1100 3000 900 -800 700 600 -500 400 -300 -200 -100 -100 4.5 -5.0 -5.5 -2.5 -3.0 -3.5 4.0 -0.5 1.0 f1 (ppm) -1.5 -2.0 0.5 0.D 2.5 2.0 1.5 1.0 4.0 35 LC In the above NMR spectrum, The peak around 3.0-3.5 is corresponding to the aldehyde group and it's a doublet, that means, there will be only one proton on its neighboring carbon

Further, the peak around 1.0. is a triplet and that confirms there will be total two hydrogen atoms on its neighboring carbons. As there are no evidence of heteroatoms from the given information, this proton is corresponds to the alkene proton Also, there are two doublets in between 0.5 to 0.0, these two protons are on the same carbon but are Cis and Trans to the neighboring proton on the neighboring carbon, hence the separate doublets. The probable structure ofthe unknown aldehyde and the approximated ppm values of the protons that support the given NMR spectrum is given below 0.4 H 3.25 0.1 H 1.0