Question

On each the following IR spectra, circle and indicate the most important stretching signal from the following choices:N-H, O-H, CEN, CEO, C-O, Top, IR spectrum of Compound 18a: C11H1402Bottom, IR Spectrum of Compound 18b: C.H120. write your answer on the corresponding square provided 100 0 1000 LOO khmer WA 000 200 1000 50 VENUHRERI- 6 18. Draw the structures of Compound 18a. and 18b. (18 pts), clearly indicate your assignments of all proton resonances (8 pts). Calculate the Unsaturation Index of each compound 3.0 Unsat. Index = (2C+2-H-X + Ny2 = 200 2.5 e = 2.00 ppm, singlet, 2H 20 f = 1.27 ppm, triplet, 3H 720 Compound 18a: C, H40, 1.27 1.5 a = 7.21 ppm, b = 7.18 ppm, doublet, 2H doublet, 2H 10 d = 2.66 ppm, quartet, 2H 2.65 27 C = 4.90 ppm, singlet, 2H 1.25 129 0.5 2.63 289 8, ppm 00 80 75 70 85 80 55 35 30 25 20 15 10 05 50 45 40 1 H,O, H,O*heat 2.0 Unsat. Index - (2C+2-H-X+N)/2 = 1.5 127 21. Compound 18b: C,H,O d = 4.58 ppm singlet, 2H e = 2.66 ppm, 721 f=1.27 ppm, triplet, 3H quartet, 2H 1.0 723 7.11 2.65 267 129 123 C = 5.15 ppm, 0.5 a = 7.22 ppm, doublet, 2H b = 7.12 ppm, doublet, 2H singlet, 1H 289 283 5.15 8, ppm 0.0 85 B.D 7.5 6.5 60 5.5 50 40 3.5 30 25 20 1.5 10 0.5 45 7