Nuclear magnetic resonance spectra alcohols

Fig. 3.53 >3C nuclear magnetic resonance spectrum of benzyl alcohol in CDC13 sweep width 200 p.p.m. Data reproduced from the Standard Carbon-13NMR Spectra Collection, Sadder Research Laboratories, Division of Bio-Rad Laboratories, Inc. 

If the unknown, neutral, oxygen-containing compound does not give the class reactions for aldehydes, ketones, esters and anhydrides, it is probably either an alcohol or an ether. Alcohols are readily identified by the intense characteristic hydroxyl adsorption which occurs as a broad band in the infrared spectrum at 3600-3300 cm-1 (O—H str.). In the nuclear magnetic resonance spectrum, the adsorption by the proton in the hydroxyl group gives rise to a broad peak the chemical shift of which is rather variable the peak disappears on deuteration. 

In general, on reaction with lithium aluminum hydride, secondary sulfonic esters are desulfonylated, with formation of the corresponding secondary alcohol. An exception is provided in an observation by Reist and coworkers, who treated 6-0-benzoyl-l,2-0-isopropyli-dene-5-O-p-tolylsulfonyl-a-D-glucofuranose, with lithium aluminum hydride in ether and obtained a product thought to be 6-deoxy-l,2-0-isopropylidene-y3-L-idofuranose, derived from an intermediate 5,6-anhydro-L-ido derivative later, Ryan and coworkers showed, from its nuclear magnetic resonance spectrum, that the product was 5-deoxy-l,2-0-isopropylidene-a-D- t/Zo-hexofuranose. The problem has been re-examined by Overend and coworkers the repetition experiment under the conditions of Reist and coworkers afforded 5-deoxy-... 

At one time, the lipid carrier was believed to be a glycerophos-phatide, but further purification showed conclusively that it is a Cjs-isoprenoid alcohol phosphate. Its nuclear magnetic resonance spectrum showed that two of its internal double bonds have the trans configuration, and that this isoprenoid alcohol differs from ficaprenol, a Cjs-isoprenoid alcohol from fig leaves, which has three internal, trans, double bonds. ... 

The assignment of these isomers was confirmed by nuclear magnetic resonance spectroscopy on a Perkin-Elmer 60 Mc./sec. NMR spectrometer, after removal of -OH by exchange with deuterium oxide. The spectrum of the cw-alcohol showed a single broad peak, while that of the trans-alcohol showed two peaks they thus resembled the spectra of the corresponding hydrocarbons (8). 

---