Question

CHO 35 3.50 -- --- ----- - -- ---3.60 6.68 7.40-17.30 - 7.20----- 7.10 --- 7.00--1-6.90--- 6.80 ---- 6.70T--- 6.60 7.35 7.16 7.37 7.5 7.0 6.0 3.5

1. Write down problem number.

2. Provide formula, HDI value, and a complete, chemically correct structure for each problem.

3. Assign signals in the 1H and 13C spectra to specific atoms, identify structural units and/or functional groups.

Example:

Problem # 3

Formula: C8H8O2

HDI: 5

1H NMR: p-substituted Ar at 7.27-7.97 ppm, benzylic CH3 group at 2.42 ppm, COOH proton at 12.9 ppm

13C NMR: carbonyl C at 167.8 ppm (ester or acid), benzylic CH3 at 21.40 ppm, 4 remaining signals are Ar carbons, two of which are quaternary, typical of a p-substituted ring

Structure:

Answer 1

Hi there, from your provided example problem #3, i just followed those instructions.

Given Molecular Formula: C9H10O3

HDI = [2C + 2 + N -H -X] / 2 = [(2 x 9) + 2 + 0 -10 -0)] / 2 = 5

Hence HDI = 5

1H NMR: p-substituted Ar at 7.14-7.37 ppm, phenolic -OH proton at 6.68 ppm, broad singlet, benzoate CH3 group at 3.60 ppm, benzyl methylene group (-CH2-) proton at 3.50 ppm

13C NMR: carbonyl C at 171.00 ppm (ester), ester methyl -CH3 at 52.24 ppm, benzylic CH2 at 41.10 ppm, 4 remaining signals are Ar carbons, two of which are quaternary, typical of a p-substituted ring

Compound name is methyl (p-hydroxyphenyl)acetate (IUPAC name: methyl 2-(4-hydroxyphenyl)acetate)

ОН

NMR assignments:

HNMR CNMR (B) HA (C) H0 HO- -0- -CH2-C- (E) 6 0-CH, 10) ng (BH HIA Assign ppm Assign. Shift (ppm) 7.36 7.15 6.68 Hem MUAH 171.00 157.89 130.87 125.90 116.24 52.24 41.10 3.6

Hope this helped you!

Thank You So Much!

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