Sodium cyanoborohydride solubilities

Sodium cyanoborohydride [25895-60-7] M 62.8, m 240-242°(dec), d28 1.20. Very hygroscopic solid, soluble in H20 (212% at 29°, 121% at 88°), tetrahydrofuran (37% at 28°, 42.2% at 62°), very soluble in EtOH but insoluble in Et20, CgH6 and hexane. It is stable to acid up to pH 3 but is hydrolysed in 12N HC1. The rate of hydrolysis at pH 3 is 10 8 that of NaBHz . The fresh commercially available material is usually sufficiently pure. If veiy pure material is required one of the following procedures must be used [5 135 1975] The NaBH3CN is dissolved in tetrahydrofuran (20% w/v), filtered and the filtrate is treated with a fourfold volume of CH2C12. The solid is collected and dried in a vacuum [Inorg Chem. 9 2146 1970]. 

Alkyl groups are not the only substituents that can be attached to boron in order to generate new borohydride derivatives. Reaction of NaBH4 with HCN gives sodium cyanoborohydride (NaBH3CN), for example, a remarkably stable reagent that does not decompose in acid solution (the pH should be less acidic than pH 3). It is soluble in THF, MeOH, H2O, HMPA, DMF and sulfolane and is unreactive, making it very... 

Sugar-modified CS Reductive N-alkylation using sodium cyanoborohydride and unmodified sugar or sugar-aldehyde derivative Enhance water solubility Drug targeting... 

Reactions.—New systems for the reduction of alkyl halides to alkanes include mixtures of lithium aluminium hydride with transition-metal chlorides (such as Ni or Co" chlorides) and some complex metal hydrides of copper, especially the THF-soluble Li4CuHs. Details of the application of sodium cyanoborohydride to the reduction of halides (and sulphonate esters) in dipolar aprotic solvents have been published. Virtually all other functional groups are inert to this convenient, mild, and efficient system, which has been used to develop a one-pot deoxygenation of primary alcohols (Scheme 39) via the iodides. The alternative cyanoborohydride reagents (55) and the polymeric (56) are also discussed. ... 

Reductive amination of the aldehyde 3 with various amines provides a ready route to the preparation of derivatives. For example, reductive amination of 3 in methanol using 1,10-diaza-18-crown afforded the water soluble crown derivative Similarly, the PEG-carbohydrate conjugates 7 and were obtained by reductive amination with glucosamine and chitosan, respectively. PEG-coated glass beads 9 were obtained from aldehyde sodium cyanoborohydride, and aminopropyl-derivatized, controlled-pore glass. We are presently examining this same reaction for coupling PEG and proteins. Also, as mentioned above, PEG amine was prepared by reductive amination with ammonium acetate. 

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