Deuterium bromide iodide

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

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. 

Benzylic halides are reduced very easily using complex hydrides. In a-chloroethylbenzene lithium aluminium deuteride replaced the benzylic chlorine by deuterium with inversion of configuration (optical purity 79%) [537]. Borane replaced chlorine and bromine in chloro- and bromodiphenylme-thane, chlorine in chlorotriphenylmethane and bromine in benzyl bromide by hydrogen in 90-96% yields. Benzyl chloride, however, was not reduced [5iSj. Benzylic chlorine and bromine in a jy/n-triazine derivative were hydrogeno-lyzed by sodium iodide in acetic acid in 55% and 89% yields, respectively [5i9]. 

The halide sequence is completely reversed chloride ion > bromide ion > iodide ion. This has caused us some problem, but as yet we have no explanation for it. In both cases there is enough evidence from other kinetic investigations and deuterium labelling to realize that the metal with the attached organic group R... 

The a- and -deuterium kinetic isotope effects in the decomposition of l-phenylethyl-[l-2H1]-dimethylphenylammonium bromide and iodide, 387-[l-2H1], and 1-phenylethyl-... 

The -deuterium KIE for the bromide and for the iodide ion reaction are significantly different and indicate that the nucleophiles are part of transition state of the rate-determining step of these reactions and the decomposition of the halides in chloroform occurs by way of an S 2 mechanism within a triple ion and not through carbocation formation. The kinetic study alone could not distinguish between the mechanistic alternatives, since the same kinetic expression would be obtained for all of the mechanisms. 

An intermolecular isotope effect, /h//d °f 200 has been reported [741, 742] for dissociative electron attachment of H2 and D2. The intermolecular deuterium isotope effects on dissociative electron attachment in hydrogen chloride, hydrogen bromide and hydrogen iodide have been determined as 1.41,1.45 and 1.66, respectively [168]... 

Presumably less nucleophilically assisted solvolyses could show higher a-deuterium isotope effects, and there is a linear relationship between the magnitude of nucleophilic solvent assistance (Table 2) and the a-deuterium isotope effect for solvolyses of 2-propyl sulpho-nates (Fig. 7). Another measure of nucleophilic assistance is the ratio k2 (OH )/, where k2 is the second-order rate constant for nucleophilic attack by OH and kx is the first-order rate constant for reaction with the solvent water, and a linear correlation was obtained by plotting the ratio versus the experimentally observed isotope effects for methyl and trideuteriomethyl sulphonates, chlorides, bromides and iodides (Hartman and Robertson, 1960). Using fractionation factors the latter correlation may also be explained by a leaving group effect on initial state vibrational frequencies (Hartshorn and Shiner, 1972), but there seems to be no sound evidence to support the view that Sn2 reactions must give a-deuterium isotope effects of 1-06 or less. 

Bis(phenylselanyl)methyllithiums 429 (R = H) are stable till 0 °C and were initially trapped with deuterium oxide, methyl iodide and benzophenone639. a-Substituted organolithium intermediate 429 (R = Me, w-CgH ), prepared with LiTMP in THF/HMPA at — 20 °C, reacted with alkyl bromides, ethylene oxide and benzaldehyde to give products 430 in good yields (Scheme 113)640. Bis(methylselanyl)methyllithiums 431 have been allowed to react with different electrophiles to afford products 432 (Scheme 113)640. Alkylated products have been deprotected with mercury(II) chloride or copper(II) chloride/copper(II) oxide, and by oxidation with hydrogen peroxide or benzeneseleninic anhydride644. Deprotection of selenoacetals to ketones can also be performed with sulfuric acid645. 

Leffek and co-workers (Leffek et al., 1960a, b) have studied the effects of a, jS and y-deuterium substitution in the n-propyl moiety of n-propyl benzenesulfonate, methanesulfonate, bromide and iodide... 

The relative proportion of extra- and intracellular fluid has been determined by the dilution technique. Chemicals of known distribution in the body fluids are administered, and the volume of a given fluid compartment can be measured by determining the concentration of these chemicals. For example, Evans blue, bromosulftalein, iodinated albumin, and iodine 131 are used to determine plasma volume. Urea, thiourea, deuterium, and tritiated water are useful for determining the total body fluids. Thiocyanate, iodide, sulfate, mannitol, sucrose, raffmose, chloride 36, chloride 38, and bromide 32 are used to determine extracellular space. 

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