Chapter 14: Q.21558-14-25P. (page 555)
Propose a structure for a compound of molecular formula C3H8O with an IR absorption at 3600 to 3200 cm-1 and the following NMR spectrum:

Short Answer

/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 14: Q.21558-14-25P. (page 555)
Propose a structure for a compound of molecular formula C3H8O with an IR absorption at 3600 to 3200 cm-1 and the following NMR spectrum:


All the tools & learning materials you need for study success - in one app.
Get started for free
Question: How many different types of protons are present in each compound?
The 1H NMR spectrum 1,2-dimethoxyethane (CH3OCH2CH2OCH3) recorded on a 300 MHz NMR spectrometer consists of signals at 1017 Hz and 1065 Hz downfield from TMS. (a) Calculate the chemical shift of each absorption. (b) At what frequency would each absorption occur if the spectrum were recorded on a 500 MHz NMR spectrometer?
Question: How many 1H NMR signals does each natural product exhibit?
a.

b.

c.

d.

Question:Propose a structure consistent with each set of spectral data:
a. C4H8Br2: IR peak at 3000–2850cm-1 ;
NMR (ppm):
1.87 (singlet, 6 H)
3.86 (singlet, 2 H)
b. C3H6Br2: IR peak at 3000–2850cm-1 ;
NMR (ppm):
2.4 (quintet)
3.5 (triplet)
c. C5H10O2: IR peak at 1740cm-1 ;
NMR (ppm):
1.15 (triplet, 3 H) 2.30 (quartet, 2 H)
1.25 (triplet, 3 H) 4.72 (quartet, 2 H)
d . C6H14O: IR peak at 3600-3200 cm-1 ;
NMR (ppm):
0.8 (triplet, 6 H) 1.5 (quartet, 4 H)
1.0 (singlet, 3 H) 1.6 (singlet, 1 H)
e. C6H14O: IR peak at 3000-2850cm-1 ;
NMR (ppm):
1.10 (doublet, relative area = 6)
3.60 (septet, relative area = 1)
f . C3H6O: IR peak at 1730cm-1 ;
NMR (ppm):
1.11 (triplet)
2.46 (multiplet)
9.79 (triplet)
Question: Rank the highlighted carbon atoms in each compound in order of increasing chemical shift.
a.

b.

What do you think about this solution?
We value your feedback to improve our textbook solutions.