Deuterium iodide

Deuterium iodide has been thermally decomposed in the temperature range 660-719 "K by Blagg and Murphy In their experiments the extent of reaction and the rate of the thermal decomposition were determined by measurement of the iodine concentration. At the end of an experiment the products were dissolved in potassium iodide solution and the Ij was titrated with thiosulfate. Table 3 lists the measured rates for the reaction... 

KINETIC DATA FOR THE THERMAL DECOMPOSITION OF DEUTERIUM IODIDE... 

Problem Determine the equilibrium constant of the homogeneous gaseous isotopic exchange reaction between hydrogen and deuterium iodide, via.,... 

Precise measurements of the effect of isotopic substitution on hyperfine Zeeman splitting effects [64] have provided the correct direction of the dipole moment for carbon monoxide, CO [65], deuterium iodide, DI [66], and carbonyl sulfide, OCS [67],... 

Deuterium iodide can only be stored in condensed form at low temperatxire. 

Ikram A, Tortie BH, PoweU BM (1993) Strucmres of solid deuterium bromide tmd deuterium iodide. Mol Phys 79 1037-1049... 

Give the prodnets expected from reaction of deuterium iodide (DI) with (a) 1,3-cycloheptadiene (b) fra -l,3-pentadiene ... 

There are three methods which are commonly used in the steroid field to replace a halogen atom by deuterium. These methods involve treatment of the halides— generally chloride, bromide or iodide—(a) with lithium aluminum deuteride, (b) with deuterium gas and a surface catalyst or (c) with zinc in O-deuterated acids or alcohols. 

An example is the preparation of 18-trideuterio 5a-steroids bearing a side chain at C-17. Labeling of this position with three deuteriums was accomplished by utilizing the Johnson procedure for steroid total synthesis. This synthesis involves, in part, introduction of the 18-angular methyl group by methylation of the D-homo-17a-keto-17-furfurylidene intermediate (243). By substituting d3-methyl iodide in this step, the C/D cis- and ra/J5-18,18,18-d3 labeled ketones [(244) and (245)] are obtained. Conversion of the C/D tra 5-methylation product (245) into 18,18,18-d3-d /-3)8-hydroxy-5a-androstan-17-one (246) provides an intermediate which can be converted into a wide variety of C-18 labeled compounds of high (98%) isotopic... 

Trimethylsulfoxonium iodide (38 g) is dissolved in deuterium oxide (170 ml) at 80-100° and anhydrous potassium carbonate (50 mg) is added. The mixture is heated on a steam bath for 1 hr, then cooled to 0° for 2 hr before filtering. The recovered solid is re-equilibrated twice more by the same procedure using fresh deuterium oxide. Yield = 33.4 g (88 %). 

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. ... 

Table 17 Secondary deuterium KIEs for the Menshutkin reactions of deuterated pyridines and alkyl iodides in nitrobenzene at 25°C.a...

The steric rather than the inductive origin of the secondary deuterium KIE is also suggested because kH/kD = 0.994 per deuterium found in the per-deuteropyridine-methyl iodide reaction is smaller (less inverse) than the kH/kn = 0.988 per deuterium found for the 4-deuteropyridine reaction. A secondary inductive KIE should be more inverse when a deuterium is substituted for a hydrogen nearer the reaction centre, i.e. at the meta- or ortho-rather than at the para-position of the pyridine ring. Thus, if the KIE were inductive in origin, the KIE in the perdeuteropyridine reaction should be more inverse than that observed for the 4-deuteropyridine reaction. If the observed KIE were the result of a steric KIE, on the other hand, a less inverse KIE per deuterium could be found in the perdeuteropyridine reaction, i.e. a less inverse KIE per deuterium would be expected if there were little or no increase in steric hindrance around the C—H(D) bonds as the substrate was converted into the SN2 transition state. Since the KIE per D for the perdeuteropyridine reaction is less than 1%, the transition state must not be sterically crowded and the KIE must be steric in origin. Finally, the secondary deuterium KIEs observed in the reactions between 2-methyl-d3-pyridine and methyl-, ethyl- and isopropyl iodides (entries 3, 7 and 9, Table 17) are not consistent with an inductive KIE. If an inductive KIE were important in these reactions, one would expect the same KIE for all three reactions because the deuteriums would increase the nucleophilicity of the pyridine by the same amount in each reaction. The different KIEs for these three reactions are consistent with a steric KIE because the most inverse KIE is observed in the isopropyl iodide reaction, which would be expected to have the most crowded transition state, and the least inverse KIE is found in the methyl iodide reaction, where the transition state is the least crowded. 

In a more recent study, Harris and co-workers (Harris et al., 1981) found that the secondary a-deuterium KIEs (Table 18) were larger (more inverse) when a poorer nucleophile was used in the SN2 reactions (22) between 3,5-disubstituted pyridines and methyl iodide in 2-nitropropane at 25°C. 

Table 23 The secondary a-deuterium and incoming nucleophile nitrogen KIEs found for the Sn2 reactions between p-substituted N,/V-dimethylanilines and methyl iodide in ethanol at 25°C.a...

Table 24 The calculated and experimental incoming nucleophile nitrogen, a-carbon and secondary a-deuterium KIEs for the SN2 Menshutkin reactions between p-substituted iV.jV-dimethylanilines and methyl iodide at 298 K.°...

Remote double labelling techniques have been used successfully in the determination of enzyme KIEs (Kiick, 1991). A variant of this technique was applied to a nonenzymatic reaction by Matsson and co-workers (Axelsson et al., 1990). They determined the primary carbon and secondary deuterium KIEs for the SN2 reaction between methyl iodide and hydroxide ion in 50% dioxane-water at 25°C. The a-carbon KIE was determined by the UC method (Axelsson et al. 1987,1991). In this method, a mixture of substrate molecules labelled with UC (tm = 20.4 min) and 14C is used. The reactants and products... 

TABLE 8. The secondary alpha hydrogen-deuterium kinetic isotope effects for the Menshutkin reaction between 3,5-disubstituted pyridines and methyl iodide in 2-nitropropane at 25 °C... 

The gas-phase reactions of the fulvene radical cation with neutral 1,3-butadiene, alkenes and 2-propyl iodide have been investigated by Russell and Gross131a using ICR mass spectrometry. Unlike ionized benzene, ionized fulvene undergoes no C—C coupling with 2-propyl iodide. On the basis of deuterium and 13C labelling, the reaction of ionized fulvene with 1,3-butadiene was suggested to occur by [6 + 4] cycloaddition to yield tetrahydroazulene radical cations. Cycloadditions of neutral fulvene were also studied in this work. 

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