Reduction by sodium

Table 7. Summary of Inorganic Reductions by Sodium Borohydride ...

Lobinine, CjgHggOgN. First isolated by Wieland, Ishimasa and Koschara who, on the evidence then available, regarded it as 2-phenacyl-l-methyl-7-)3-hydroxypropylhexamethyleneimine, CjgHjjOjN (XXI), which was modified to (XX) in 1989. It furnishes an oxime (B. HCl, m.p. 182°) and a benzoyl derivative (B. HCl, m.p. 146-7°). On reduction by sodium in acetic acid it is converted into the unsaturated dihydric alcohol for which th original name lobinol has been changed to /3-lobinanidine,... 

Hydrocotarnine, C12HJ5O3N. HjO. This basic hydrolytic product of narcotine occurs in opium. It crystallises from light petroleum in colourless plates, m.p. 55-5-56-5°, and yields well-crystallised salts of which the hydrobromide, B. HBr, m.p. 236-7°, is sparingly soluble in water. On oxidation, hydrocotarnine is converted into cotarnine, and on reduction by sodium in alcohol it yields hydrohydrastinine (p. 164) by loss of a mcthoxyl group. 

Its low specific gravity indicates that it is an open-chain compound, and from its easy reduction by sodium and alcohol, into dihydroaplotaxene, and by hydrogen and platinum black into normal heptadecane OjjHj,., it is evident that aplotaxene is a tetraolefinic normal chain hydrocarbon. 

The interaction in Equation (173) is exothermic and occurs with the generation of 713 Kcal of heat per 1 kg of mixture, as reported by Bose and Gupta [538]. Kolchin and Vol dman [577] investigated the thermal effects of tantalum and niobium reduction by sodium from molten K2TaF7 and K2NbF7, respectively. The interaction with K2NbF7 is similar to that shown is Eqaution (173). It was found that the thermal effects in the case of tantalum and niobium correspond to 385 cal/g and 510 cal/g at 1000°C, respectively. 

Reduction by sodium dithionite. A small amount of sodium dithionite, solid or in solution, is added to a luciferase solution made with 50 mM phosphate, pH 7.0, containing 50 pM FMN. The amount of dithionite used should be minimal but sufficient to remove oxygen in the solution and to fully reduce the flavin. The solution made is injected into an air-equilibrated buffer solution containing a long-chain aldehyde and luciferase to initiate the luminescence reaction. With this method, the reaction mixture will be contaminated by bisulfite and bisulfate ions derived from dithionite. 

Norbomenone 26 undergoes reduction by sodium borohydride under kinetic conditions to produce 5% exo- (i.e., endo attack) and 95% endo- (i.e., exo attack) 2-norbomeol. This leads to the partial rate constants of 11.4 for exo and 0.6 for endo attack (relative rate with respect to the rate of LiAlH reduction of cyclopen-tanone (1.00)) [80]. In the saturated 2-norbomanone 25, the values are 4.55 for exo and 0.74 for endo attack. Thus, the introduction of the double bond enhances the... 

Addition of lithiated heterocycles to aldonolactones yields carbon-linked nucleosides (56). Thus, the reaction of 2,3 5,6-di-O-isopropylidene-L-gu-lono-1,4-lactone (9b) or 2,3-O-isopropylidene-D-ribono-l,4-lactone (16a) with various lithiated heterocycles gave gulofuranosyl derivatives 53a-g or ribofuranosyl derivatives 54b,c. Gulonolactols 53a-g and ribonolactols 54b,c were acetylated with acetic anhydride in pyridine to yield their acetyl derivatives. The stereochemistry of compounds 53a-g and 54b,c was discussed in terms of the Cotton effect of circular-dichroism curves of the ring-opened alcohols formed upon reduction by sodium borohydride. The configuration at C-l of 53g was proved by means of X-ray analysis (57,58). 

Wee, T. G., Frey, P. A. Studies on the mechanism of action of uridine diphosphate galactose 4-epimerase. Substate dependent reduction by sodium borohydride. J. Biol. Chem. 248, 33—40 (1973). 

Even if the electrochemical behaviour of the complex is unknown, chemical two-electron reduction (by sodium or potassium metal) affords the corresponding dianion [LFe—N=N—FeL]2-, the molecular structure of which is substantially similar to that of the neutral precursor.62 In the dianion, the Fe-N(dinitr0gen) distance remains essentially unaltered with respect to the neutral congener, whereas the N-N distance elongates by about 0.06 A. Such a lengthening of the N=N bond agrees with theoretical results which show that the two added electrons enter N-N antibonding orbitals. 

Silyl radicals are also involved as the reactive intermediates during one-electron reduction of bromosilanes. As an example. Reaction (1.7) shows the reduction by sodium of a silyl bromide to produce a persistent radical, which has been characterized by EPR spectroscopy [12]. 

The superiority of catalytic hydrogenation of the readily available D-glucose as a laboratory method and the commercial availability of sorbitol has rendered the earlier reductions by sodium amalgam of... 

This assumption of Pauly s was confirmed by Knoop and Windaus, who found that histidine is resistant to reduction by sodium and alcohol whereas the pyrimidine rii is very unstable towards this reagent. On reducing Frankel s oxydesaminohistidine, which is obtained from histidine by the action of nitrous acid, they obtained /8-imidazole-propionic acid. This compound was identical with the synthetical product prepared from glyoxylpropionic acid, ammonia and formaldehyde — ... 

Herz salts (89) made from 3-aminopyrazoles (Section 4.11.8.5) give pyrazolo[3,4-r/]-l,2,3-thia-diazoles (90) when subjected to reduction by sodium dithionite followed by nitrozation (Equation (12)) <84JOCl224>. If the reduction is carried out in an inert atmosphere the disulfide (91) is formed which upon nitrozation gives (90) in 63% yield. Notably, benzo-fused Herz salts give benzo-1,2,3-thiadiazoles simply on treatment with nitrozating mixture <84CHEC-I(6)916>. 

Bipyridine is catalytically hydrogenated to 3,3 -bipiperidine, and the reduction may also be accomplished electrochemically. Erythro and threo forms of 3,3 -bipiperidine are produced by the latter method. 3,3 -Bipyridine is reduced with difficulty by means of tin and hydrochloric acid or sodium and alcohol. Some l,2,3,4,5,6-hexahydro-3,3 -bipyridine (also known as nicotidine) is produced, but several other partly reduced 3,3 -bipyridines are obtained as well. 3,3 -Bipyridine is reported to give a radical anion in tetrahydrofuran on reduction by sodium. Although there is some doubt about the authenticity of the starting material (see Section 3,4 -bipyridine is reported to be fully reduced to 3,4 -bipiperidine by catalytic hydrogenation and to l, 2, 3, 4, 5, 6 -hexahydro-3,4 -bipyridine by tin and hydrochloric acid. ... 

Explain the higher reactivity of acetone (propanone) compared to methyl acetate (CH3CO2CH3) toward reduction by sodium borohydride. 

IV,B,2). Successful reduction by sodium borohydride has been reported only for quaternary salts 161228 and 16265 the reported sites of reduction differed. 

Reduction by sodium amalgam or by zinc and an acid produces sulphurous acid s... 

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