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Sodium borohydride is soluble in protic solvents such as water and lower alcohols. It also reacts with these protic solvents to produce H 2; however, these reactions are fairly slow. Complete decomposition of a methanol solution requires nearly 90 min at 20 °C. [11] It decomposes in neutral or acidic aqueous solutions, but is stable at pH 14. [9]
Since, aldehydes reduce more easily than ketones, they require milder reagents and milder conditions. At the other extreme, carboxylic acids, amides, and esters are poorly electrophilic and require strong reducing agents. [17] The idealized equation for the reduction of a ketone by sodium borohydride is: 4 RCOR' + NaBH 4 → NaB(OCHRR') 4
At low pH values, it efficiently reduces aldehydes and ketones. [7] As the pH increases, the reduction rate slows and instead, the imine intermediate becomes preferential for reduction. [ 7 ] For this reason, NaBH 3 CN is an ideal reducing agent for one-pot direct reductive amination reactions that don't isolate the intermediate imine.
Since sodium cyanoborohydride is a mild reducing agent, it gives good chemoselectivity for reaction with certain functional groups in the presence of others. For example, sodium cyanoborohydride is generally incapable of reducing amides, ethers, esters and lactones, nitriles, or epoxides. [8]
Sodium borohydride (Na BH 4) Ferrous compounds that contain the Fe 2+ ion, such as iron(II) sulfate; Stannous compounds that contain the Sn 2+ ion, such as tin(II) chloride; Sulfur dioxide (sometimes also used as an oxidizing agent), Sulfite compounds; Dithionates, e.g. Na 2 S 2 O 6; Thiosulfates, e.g. Na 2 S 2 O 3 (mainly in analytical ...
Lithium borohydride (LiBH 4) is a borohydride and known in organic synthesis as a reducing agent for esters.Although less common than the related sodium borohydride, the lithium salt offers some advantages, being a stronger reducing agent and highly soluble in ethers, whilst remaining safer to handle than lithium aluminium hydride.
Reductions with hydrosilanes are methods used for hydrogenation and hydrogenolysis of organic compounds.The approach is a subset of ionic hydrogenation.In this particular method, the substrate is treated with a hydrosilane and auxiliary reagent, often a strong acid, resulting in formal transfer of hydride from silicon to carbon. [1]
Sodium metaborate can be converted to sodium borohydride by several methods, including the reaction with various reducing agents at high temperatures and pressure, [12] or with magnesium hydride MgH 2 by ball milling at room temperature, followed by extraction of the Na[BH 4] with isopropylamine. [13] [10] NaBO 2 + 2 MgH 2 → Na[BH 4] + 2 MgO