Nuclear magnetic resonance spectra ethers

C Nuclear magnetic resonance spectrum, acetaldehyde, 732 acetophenone, 732 anisole, 672 benzaldehyde, 732 benzoic acid, 771 p-bromoacetophenone, 449 2-butanone, 449, 732 crotonic acid. 771 cyclohexanol, 634 cyclohexanone, 732 ethyl benzoate, 477 methyl acetate, 443 methyl propanoate, 450 methyl propyl ether, 672... 

Tris(dimethylamino)arsine (d2o 1.1248 nd 1.4848)3 is a colorless liquid which is readily hydrolyzed to form arsenic (III) oxide and dimethylamine when brought into contact with water. The compound is soluble in ethers and hydrocarbons. The product is at least 99.5% pure (with respect to hydrogen-containing impurities) as evidenced by the single sharp peak at —2.533 p.p.m. (relative to tetramethylsilane) seen in the proton nuclear magnetic resonance spectrum of the neat liquid. 

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. 

Using diethylene glycol diethyl ether, b.p. 188°, as the solvent, it has been shown from the nuclear magnetic resonance spectrum and infrared spectrum of the crudely distilled product that A,A, A"-trimethylborazine is obtained in comparable yield. However, the product cannot be separated efficiently from the solvent. 

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-... 

Transfer the ether to a tared reaction tube and evaporate the solvent to leave crude triphenylmethane. Remove a sample for melting point determination and recrystallize the residue from an appropriate solvent, determined by experimentation. Prove to yourself that the compound isolated is indeed triphenylmethane. Obtain an infrared spectrum and a nuclear magnetic resonance spectrum. 

The 4-methyl ether of (23), prepared from 2,3,4-tri-O-methyl-D-glucose, showed a nuclear magnetic resonance spectrum similar to that of (24), and it probably has a similar structure, corresponding to the 4-methyl ether of (25). ... 

The enol ether (23) has been obtained from 2-0-methyl-D-glucose and from 2,3-di-O-methyl-D-glucose. Klemer, Lukowski, and Zerhusen isolated a crystalline form of (23) with C ]d + 16° no mutarotation was mentioned. They assumed their compound to be pyranoid by analogy with (24). The nuclear magnetic resonance spectrum of the reaction mixture from 2,3-di-O-methyl-D-glucose showed the presence of equimolar amounts... 

The similarity in the nuclear magnetic resonance spectrum of the diacetate of the phenylosazone of the cts-glycosulos-3-ene (37 R = H) and that of the monoacetate of the phenylosazone of the 6-methyl ether (37 R = Me) established the ds configuration for the compound (32) isolated by Wolfrom, Wallace, and Metcalf. ... 

The proton nuclear magnetic resonance spectrum of the thorium hydride shows a resonance at 6 0.90 due to the hydride. The source of the hydride has been shown to be one of the hydrogen atoms of tetrahydrofuran since conducting the reaction in perdeuterotetrahydrofuran yields the monodeuteride. Tetrahydrofuran is essential since boiling C1M[N(SiMe3)2]3 with NaN(SiMe3)2 in benzene, toluene, isooctane, or diethyl ether results in isolation of unreacted C1M[N(SiMe3)2]3 ... 

Comparison of the nuclear magnetic-resonance spectrum of methyl 4-0-acetylmycaroside with the spectra of some model compounds, and the failure to obtain an isopropylidene derivative of methyl a-L-mycaroside, led Foster and coworkers to propose for mycarose the ij-xylo configuration. However, the more detailed analysis made of the nuclear magnetic-resonance spectrum of di-O-acetylmycarose by Hofheinz and coworkers as well as the stereospecific syntheses of mycarose by Korte and coworkers and by Woodward and coworkers, leave little doubt that mycarose is 2,6-dideoxy-S-C-methyl-L-nho-hexose (61) and that cladinose is its 3-methyl ether (62). 

Fig. 4. Temperature-dependent proton nuclear magnetic resonance spectrum showing the N-methyl (left) and dimethylsilyl (right) resonances of lithium bis(ferr-butyldimethylsi-lyl)methylhydrazine in diethyl ether. Only the N.Af -bis(silyl) isomer is present in detectable amount.

Attempts to generate thiocamphor (5)-methylide (44) by the addition of diazomethane to thiocamphor and subsequent N2-elimination from the [3-1-21-cycloadduct 43 led to enethiol ether 45 via a 1,4-H shift (Scheme 5.17). The formation of an unstable intermediate 43 was proposed on the basis of the proton nuclear magnetic resonance ( H NMR) spectrum of the crude mixture. The postulated intermediate 44 could not be intercepted by dipolarophiles or methanol, and did not undergo electrocyclization to give the corresponding thirrane (41). 

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