Sodium borohydride, 98%
|UN#:||UN1426||Hazard Class:||4.3||Packing Group:||I|
|Alternate Name:||Sodium tetrahydridoborate|
Pricing and Availability
|Size||($) Price||Your Price||Quantity||Options||Availability|
|Formula:||NaBH4||Melting point:||400° dec.|
The reduction of aldehydes and ketones to alcohols occurs in alcoholic or aqueous media. For highly selective reduction of aldehydes in the presence of ketones, see: Synth. Commun., 18, 1927 (1988). For enantioselective reduction, see L-tert-Leucine, L13707. Borohydride reductions can be carried out in organic solvents, e.g. toluene, under phase-transfer conditions, amenable to scale-up: Org. Process Res. Dev., 1, 287 (1997).
Hydroboration of olefins has also been reported under similar conditions: Synlett, 997 (2000).
Acid chlorides are readily reduced to alcohols; controlled reduction at -78o to give the aldehyde has been reported; see, e.g.: Synth. Commun., 12, 839 (1982). See also Bis(triphenylphosphine)copper(I) borohydride, A13730. For an indirect method of reduction, see Triethyl phosphite, L00339.
A vast number of modified borohydride reagents have been reported, with the objective either of increasing the reducing power or improving selectivity. Many examples involve combinations with metal salts:
LiCl: reduction of amino acids via Me esters: Tetrahedron Lett., 39, 917 (1998). CaCl2: selective 1,2-reduction enones: Chem. Lett., 1847 (1991). CeCl3: increased selectivity for 1,2-reduction of enones: J. Chem. Soc., Chem. Commun., 601 (1978); reduction of ketones in the presence of aldehydes: J. Am. Chem. Soc., 101, 5848 (1979). CuCl: dehalogenation of aryl iodides and bromides: J. Org. Chem., 54, 5308 (1989); reduction of nitro compounds: Chem. Ind. (London), 75 (1984). CuSO4: reduction of esters, alkenes, nitriles and nitro compounds; amides and acids inert: Synlett, 419 (1990) [but see also Synlett, 79 (1993): Cu(OAc)2 preferred for reduction of nitro-groups]; reduction of azides: Synth. Commun., 24, 549 (1994). NiCl2: generation in situ of nickel boride, as an alternative to Raney nickel for desulfurizations: Synth. Commun., 16, 779 (1986); J. Chem. Soc., Chem. Commun., 819 (1990); J. Org. Chem., 57, 1986 (1992); 58, 2407 (1993); phenols and enols have also been deoxygenated: J. Chem. Soc., Perkin 1, 1897 (1992), and aryl nitrile reduced to benzylamines: Synth. Commun, 32, 1265 (2002). For conversion to Zn(BH4)2, see Zinc chloride, A16281. InCl3: radical reducing system - alternative to Bu3SnH: J. Am. Chem. Soc., 124, 906 (2002) .
Reductive alkylation of amines can be effected with NaBH4/formaldehyde; see e.g.: Synthesis, 743 (1980); or TFA: Synthesis, 709 (1987). See also Sodium cyanoborohydride, 87839. Reductive alkylation of aromatic amines with a variety of aldehydes and ketones has been reported, using NaBH4/H2SO4: Synthesis, 121 (1993).
The combination of borohydride and iodine (in situ borane) reduces acids to alcohols: J. Org. Chem., 56, 5964 (1991); amino acids to amino alcohols: J. Org. Chem., 58, 3568 (1993); and effects reduction of esters, amides and nitriles, as well as hydroboration of alkenes: Tetrahedron, 45, 4623 (1992). See also Boron trifluoride diethyl etherate, A15275, and Sodium triacetoxyborohydride, B22060.
For a brief feature on uses of the reagent in synthesis, see: Synlett, 182 (2005).
Monograph: J. Seyden-Penne, Reductions by the Alumino- and Borohydrides In Organic Synthesis, 2nd ed., Wiley, N.Y. (1997).
|Harmonized Tariff Code:||2850.00|
GHS Hazard and Precautionary Statements
In contact with water releases flammable gases which may ignite spontaneously. Toxic if swallowed. Toxic in contact with skin. Fatal if inhaled. Causes severe skin burns and eye damage. Causes serious eye damage.
Handle under inert gas. Protect from moisture. IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician. IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Specific treatment is urgent (see label). Rinse mouth. Remove/Take off immediately all contaminated clothing. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.
Risk & Safety
|Contact with water liberates highly flammable gases. Toxic by inhalation, in contact with skin and if swallowed. Causes burns.|
|Keep away from living quarters. Keep container tightly closed and dry. Keep container in a well ventilated place. When using do not eat or drink. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. Take off immediately all contaminated clothing. Take precautionary measures against static discharges. Wear suitable protective clothing, gloves and eye/face protection. In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible). This material and/or its container must be disposed of as hazardous waste.|