The spectroscopic data and molecular formulas for two compounds (A and B) are given on pages 3 and 7, labelled Problem A and Problem B respectively. Deduce the structures of compounds A and B. As part of your answer you should: (i) Calculate the double bond equivalents (DBE) for each molecule. (ii) Assign the 'H NMR spectra completely, rationalise the number of peaks, relative integral, their multiplicity or splitting pattern where appropriate. (iii) Rationalise the 13C NMR spectra. (iv) Rationalise all numbered peaks in the mass spectra and IR spectra. (v) Provide a brief logical explanation for how you arrived at unambiguous structures for compounds A and B. Problem A IR Spectrum qud tim 1690 4000 3000 2000 1800 1200 a00 0.0 V (am Mass Spectrum 0.5 105 80 60 UV spectnam M 134 1.0 40 1.075 mg/10 i pah leng0 10 om sdivent: ethanal 120 160 m/e 40 80 200 240 280 200 250 300 350 2 (nm) 13C NMR Spectrum (1260 MHZ, CDCI, soulon) DEPT CHt CHt CHt proton decoupled solve 200 160 120 80 40 6 (ppm) H NMR Spectrum (s00 MHz. COCI, sokudon pansions xpansien 76 pom 29 1.3 11 ppm TMS 10 7. 6. 4 5 (ppm) atsobance yad e jo wwww Problem B 1729 IR Spectrum 4000 3000 2000 1600 1200 800 V (cm 100 Mass Spectrum UV Spectrum 177 a0 Aman 240 nm (log,g > 4.0) 135 M 1E 80 120 160 m/e 40 200 240 280 1aC NMR Spectrum (100.0 MR, COci, skton DEPT O CHt aHt proton decouped solrt 200 160 120 80 40 0 5 (ppm) H NMR Spectrum (400 M. CDC, sition) apanskon 7.5 PPM TMS 10 6. 4 3 2. 8 (ppm) yed ose oN