Deuterated tetrahydrofuran

The areas of the H20, CF3COOH, and tetrahydrofnran peaks were measured by the method of triangulation (peak height times width at half-peak height). One of the tetrahydrofuran peaks (the deuterated tetrahydrofuran contains about 2% of the protonated material) was used as an internal standard. All peak areas were corrected to a standard peak area for tetrahydrofuran. In this way instrument errors owing primarily to changes in the field were compensated. 

Furan containing 5%-rhodium-on-alumina shaken under an initial deuterium pressure of 800 p. s. i. g. until Dg-uptake is complete after ca. 2 hrs. tetra-hydrofuran-2,3,4>5-d4. Y ca. 100%. F. deuterated tetrahydrofurans s. E. R. Bissell and M. Finger, J. Org. Chem. 24, 1259 (1959). 

Complete exchange of protons in a sterically unhindered position a to a carbonyl group can be achieved by heating a solution of the ketone in O-deuterated solvents in the presence of an acid or base catalyst, the latter being the more effective. The most commonly used solvents are methanol-OD, ethanol-OD, and the aprotic solvent anhydrous tetrahydrofuran or dioxane mixed with deuterium oxide. Under alkaline conditions the exchange rate in 153 2 14,164 stcroids, for example, is usually... 

Jardine and Brown reported that the product obtained on treatment of indole magnesium iodide in ether with deuterium oxide in tetrahydrofuran was deuterated to the extent of about 50% in both the 1- and 3-positions of the indole nucleus. ... 

In the deuterated 9-methylffuorenyl system (46), Cram and co-workers found retention of configuration in tetrahydrofuran with ammonia or a primary amine as base.127 Streitwieser has obtained similar results with benzyl systems in cyclohexylamine with cyclohexylamide as base.128 Cram s proposed mechanism is shown in Scheme 6. In dimethylsulfoxide, the exchange and racemization... 

Tetrahydrofuran-2,3,4,5-d4 was obtained by Bissell and Finger198 by deuteration of furan under pressure using Rh/Al203/D2. 

As already mentioned, the 2-proton resonance undergoes such a large downfield shift in tetrahydrofuran, that it often overlaps the complex benzenoid multiplet. In these cases, the location of the 2-proton resonance was usually determined by decoupling it from the 1-proton by rapid base-catalyzed exchange of the latter with a trace of indolyl-sodium38 and observing which peak in the NMR spectrum collapsed from a quartet (Jl 2 = 2A Hz J2 3 = 3.3 Hz)29,30 to a doublet. Coupling to the N-proton can also be eliminated by deuteration (Fig. 2A and B). 

The mechanism of 1,2,3,4-tetramethylnaphthalene formation from 2-butyne and triphenyltris(tetrahydrofuran) chromium(iii) has been clarified by using deuterated compounds . For instance, the reaction of (5) with 2-butyne leads to a mixture of 1,2,3,4-tetramethylnaphthalenes (6 and 7). The latio kulkn is 2-7+ 0-1. This result. 

The ability of 1,3-dithiolium salts to add hydride ions has been widely studied. 2-Unsubstituted salts as well as 2-alkyl or 2-aryl, 2-amino, and 2-methylthio derivatives are easily reduced to give 1,3-dithioles in excellent yields (Eq. 38). Reducing agents are sodium hydrosulfide in ethanoF sodium borohydride in methanol, ethanol, or tetrahydrofuran - lithium aluminium hydride or deuter-ide in ether or sodium borodeuteride in acetonitrile. ... 

After the exchangeable hydrogens in dianion (III) were replaced with deuterium to a considerable extent by treating the tetrahydrofuran solution of disodium dianion (III) 2 Na+ with deuterium gas at 44°, the deuterated positions in this complex were studied, which revealed that only the hydrogen at the 9- or 10-positions of dianion (III) was exchanged with deuterium. The difference in the behavior of the EDA complexes in solution from that of the film is associated with the ion pair linked together by solvent molecules. 

Thus, treatment of (la,5a,7a)-bicyclo[3.2.0]heptane-l,7-diol with tosyl chloride in pyridine and rearrangement of the resulting monotosylate with one equivalent of potassium /erf-butoxide in tetrahydrofuran for ten minutes gave the tran.s-bicyclo[4.1.0]heptan-2-one trans-5) in 83% yield. When the reaction was allowed to proceed for 19 hours with two equivalents of potassium terf-butoxide, cw-bicyclo[4.1.0]heptan-2-one (cis-S) was isolated in 73% yield most likely this arises from initial formation and subsequent isomerization to the cis-ketone. When the rearrangement was run in deuterated teri-butyl alcohol the product contained less than 33 mol% of deuterium (17% -d, 14% 2-d and 2% 3-d) indicating that the rearrangement proceeds primarily without any kind of enolization. ... 

Methylation of cyclopropylidenetriphenylphosphorane (1) can be achieved by reaction with iodomethane in tetrahydrofuran, while protonation (or deuteration) of 1 is performed with anhydrous hydrogen bromide (or deuterium bromide) in inert solvents. ... 

Fig. 10.17. Time-domain CP/MAS NMR spectra of pure deuterated-PMMA and deuterat-ed-PMMA/PVPh = 18.8/81.2 (a) Only a very weak signal due to CP from residual H is observed for deuterated-PMMA (b) time-domain signal of a partially phase-separated blend cast from tetrahydrofuran and (c) time-domain signal of a homogeneous blend cast from methylethylketone. (Reprinted with permission from Ref. [134]. 1993 American Chemical Society, Washington, DC.)...

Cioffi et al., who previously has studied the Raney Nickel catalyzed hydrogen-deuterium exchange of a model carbohydrate (l-O-methyl-yS-n-galactopyranoside) under ultrasonic irradiation, have extended their investigations into the microwave area [58]. Using a D20-tetrahydrofuran (THF) solvent mixture the above compound could rapidly (<10 min) be deuterated with 86% incorporation at one site and an even better incorporation (91%) for sucrose other sites were labeled less extensively. 

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