Question

When comparing the spectra for the starting material and the product – where do you observe the biggest change(s)?

2-hydroxy-3-methoxybenzoic acid HN MR (600 MHz, DMSO-do) -251DMS0-d6 -13.96 1139 ;2.38 7:21 7.20 L89- 6.85 17.36 .6.84 380 он он ܢ0-Hac 0.98- ܓ104 107z 3.00- 14.5 14.0 13.5 13.0_12.5 12.0 115 11. 010.5_10.0 9. 5 _8.0 7. 5 7 . 0 6.5 _6. 0 5 . 5 5 .0 4. 5 4 .0 _3.5 _3.0 _2.5 9.0 _8.5 f1 (ppm)

Answer 1

Ans:---

Here in starting material contaning benzoic acid as functional group. And also ortho Hydroxy group is their. The main resion for deshielding of carboxylic acid proton upto 14 delta ppm due to Hydrogen Bonding effect. Due to this proton can easilly change it's Spain by applied magenetic field.

In next NMR Spectra ortho hydroxy Benzaldehyde present but their is nothing an hyderogen bonding hense chemical shift occour at 11 delta ppm. This is an Major differance in chemical Shift values.

Also Aromatic one proton get chang their chemical shift values because due to An Electron withdrawing nature of an Functional group. In first acid is present nmr value of ortho proton to acid get deshielded 11 ppm.

And secound example values are decreses due to nature of electron withdrowing group and Hydrogen bonding effect.

Summery: Here an Factor Affecting on Chemical Shift values are important to describe the NMR spectra.