Question

Spectroscopy Unknown Pre-Quiz 5 5 points - Tuesday Lecture (due by 11:59 pm EST 3/16/2020) Spectroscopy Unknown. The spectra and data provided were obtained from a pure organic molecule. For 'H NMR Spectra, the integral is given in number of hydrogens (#H) or as a relative ratio. Important coupling constants (-values) are listed next to the peaks for some examples. For some spectra, an inset (grey box) is also given showing a "zoom-in" on an important part of the spectrum. Submit your answer at: Mass Spectrum (not shown): [M] = 162 (100%)m/2 IR Spectrum (not shown): 3090, 2985, 1745, 1610, 1500 cm (all listed are strong (s) unless otherwise indicated) "H NMR Spectrum (400 MHz, CDCI3, 25 °C) td (J= 8, 2 Hz) td (J= 8, 2 Hz) dd (J= 8, 2 Hz) dd (J = 8, 2 Hz) + 14 14 14 14 PPM 13C NMR Spectrum (with DEPT), proton-decoupled (125 MHz, CDC 3, 25 °C) |(CH3) (C) (C) (CH) (CH) (C) (CH) (CH) 160 140 120 100 ... ' 60 ' 40

Could someone find the structure of this molecule? I'm having alot of trouble. And could you explain how you found it? If its just structure, thats okay.

Answer 1

The provided spectral data information have been analysed and the structure of the unknown is proposed as 3,3-dimethylisobenzofuran-1-one. The detail explanation for the structure prediction of the lactone is explained as below.

The structure of unknomen is pooposed as to them Name - 3,3-dimethylisobenzofuran-1-one. Mass spectrum. (m/2) : calculated to Golio I abserved at - 16216 Invar, o in ppm) - 7.9 (dd, in , Arl , H7, J = 8, 242), 7.6 td, in, Art 45, 1-8, 242) ,7.49 (Ad, tn, ArH, H6, J = 8, 242) 7.3 (dd, in, Art, H4, I = 8, 242) , 1.5 (Singht, 64, 2XCH3, 410 & Hil). 43 C NMR Co in ppm) : - 169 (-6, C4), 153 (-¢- Cs) , 133 (C1, C5) 1300CH, 167 129 (-&- (a), 126 con 6) 122 (en (4) 8766, C3), 28(2X CH3 Go & G1). TR com') : _ 3090 (CH, sp² sbatch), 2985 (C-H, 883 for allane), 1745 CC=0, streetch ferlactone), 1610 & 1500 & C=C, for aromatic sing). the above spectral data have excellent match to the above proposed structure.