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{{chembox
{{chembox
|Verifiedfields = changed
| Verifiedfields = changed
|Watchedfields = changed
| Watchedfields = changed
|verifiedrevid = 438800960
| verifiedrevid = 438800960
|Name = Sodium cyanoborohydride
| Name = Sodium cyanoborohydride
|ImageFile = Sodium-cyanoborohydride-2D.png
| ImageFile = Sodium-cyanoborohydride-2D.png
|ImageName = Sodium cyanoborohydride
| ImageFile1 = Sodium cyanoborohydride.jpg
| ImageName = Wireframe model of sodium cyanoborohydride
⚫
|OtherNames = Sodium cyanotrihydridoborate
| ImageName1 = 3D molecular structure of sodium cyanoborohydride
⚫
|Section1={{Chembox Identifiers
⚫
| OtherNames = Sodium cyanotrihydridoborate
| IUPACName = Sodium cyanoboranuide
⚫
| Section1 = {{Chembox Identifiers
|CASNo_Ref = {{cascite|correct|CAS}}
|CASNo_Ref = {{cascite|correct|CAS}}
|CASNo = 25895-60-7
|CASNo = 25895-60-7
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|SMILES = [BH3-]C#N.[Na+]
|SMILES = [BH3-]C#N.[Na+]
}}
}}
|Section2={{Chembox Properties
| Section2 = {{Chembox Properties
|Formula = {{chem2|Na[BH3(CN)]}}
|Formula = {{chem2|Na[BH3(CN)]}}
|Na=1|B=1|H=3|C=1|N=1
|Na=1|B=1|H=3|C=1|N=1
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|MeltingPt_notes = decomposes
|MeltingPt_notes = decomposes
}}
}}
| Section3 = {{Chembox Structure
| Section3 = {{Chembox Structure
| Coordination = 4 at boron atom
| Coordination = 4 at boron atom
| MolShape = [[Tetrahedral molecular geometry|Tetrahedral]] at [[boron]] atom
| MolShape = [[Tetrahedral molecular geometry|Tetrahedral]] at [[boron]] atom
}}
}}
|Section7={{Chembox Hazards
| Section7 = {{Chembox Hazards
|ExternalSDS = Sigma Aldrich<ref>{{Sigma-Aldrich|sial|id=42077|name=Sodium cyanoborohydride |accessdate=2014-11-09}}</ref>
|ExternalSDS = Sigma Aldrich<ref>{{Sigma-Aldrich|sial|id=42077|name=Sodium cyanoborohydride |accessdate=2014-11-09}}</ref>
|GHSPictograms = {{GHS02}}{{GHS05}}{{GHS06}}
|GHSPictograms = {{GHS02}}{{GHS05}}{{GHS06}}
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|TLV-TWA = 5 mg/m3
|TLV-TWA = 5 mg/m3
}}
}}
|Section9={{Chembox Related
| Section9 = {{Chembox Related
|OtherAnions = [[Sodium borohydride]]
|OtherAnions = [[Sodium borohydride]]
|OtherCompounds = [[Lithium aluminium hydride]]
|OtherCompounds = [[Lithium aluminium hydride]]
}}
}}
}}
}}
'''Sodium cyanoborohydride''' is the [[chemical compound]] with the formula {{chem2|Na[BH3(CN)]|auto=1}}. It is a colourless salt, but commercial samples can appear tan. It is widely used in [[organic synthesis]] for the reduction of [[imine]]s. The salt tolerates aqueous conditions.<ref name=EROS>{{cite encyclopedia|author=Robert O. Hutchins |author2=MaryGail K. Hutchins |author3=Matthew L. Crawley |title=Sodium Cyanoborohydride|encyclopedia=Encyclopedia of Reagents for Organic Synthesis|year=2007|pages=rs059.pub2 |publisher=John Wiley & Sons|doi=10.1002/047084289X.rs059.pub2|isbn=978-0-471-93623-7}}</ref>
'''Sodium cyanoborohydride''' is a [[chemical compound]] with the formula {{chem2|Na[BH3(CN)]|auto=1}}. It is a colourless salt used in [[organic synthesis]] for [[Redox|chemical reduction]]; specifically, to reduce [[Imine|imines]] to [[Amine|amines]].<ref>{{Cite web |title=Common Organic Chemistry - Home Page |url=http://www.commonorganicchemistry.com/ |access-date=2023-12-05 |website=www.commonorganicchemistry.com}}</ref> The salt tolerates aqueous conditions.<ref name=EROS>{{cite encyclopedia|author=Robert O. Hutchins |author2=MaryGail K. Hutchins |author3=Matthew L. Crawley |title=Sodium Cyanoborohydride|encyclopedia=Encyclopedia of Reagents for Organic Synthesis|year=2007|pages=rs059.pub2 |publisher=John Wiley & Sons|doi=10.1002/047084289X.rs059.pub2|isbn=978-0-471-93623-7}}</ref>


==Use==
==Use==
Owing to the presence of the electron-withdrawing [[cyanide]] substituent, {{chem2|[BH3(CN)]−}} is less reducing than is [[sodium borohydride|{{chem2|[BH4]−}}]].<ref name="Reitz-2002">{{cite journal |last1=Baxter |first1=Ellen W. |last2=Reitz |first2=Allen B. |title=Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents |journal=Organic Reactions |date=9 January 2002 |pages=1–714 |doi=10.1002/0471264180.or059.01|isbn=0-471-26418-0 }}</ref> As a mild reducing agent, it is used to convert [[imine]]s to [[amine]]s.<ref name="Christen-1997">{{cite book |last1=Christen |first1=Hans |last2=Meyer |first2=Gerd |title=Grundlagen der allgemeinen und anorganischen Chemie |date=1997 |publisher=Salle + Sauerländer |isbn=978-3-7935-5493-6 |page=824 |edition=1}}</ref>
Sodium cyanoborohydride is a mild reducing agent that is often used to convert [[imine]]s to [[amine]]s.<ref name="Christen-1997">{{cite book |last1=Christen |first1=Hans |title=Grundlagen der allgemeinen und anorganischen Chemie |last2=Meyer |first2=Gerd |date=1997 |publisher=Salle + Sauerländer |isbn=978-3-7935-5493-6 |edition=1 |page=824}}</ref> Its mild reducing qualities are owing to the presence of the electron-withdrawing [[cyanide]] substituent, {{chem2|[BH3(CN)]−}}. This structure causes it to be less reducing than is [[sodium borohydride|{{chem2|[BH4]−}}]].<ref name="Reitz-2002">{{cite journal |last1=Baxter |first1=Ellen W. |last2=Reitz |first2=Allen B. |title=Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents |journal=Organic Reactions |date=9 January 2002 |pages=1–714 |doi=10.1002/0471264180.or059.01|isbn=0-471-26418-0 }}</ref>


It is especially favored for [[reductive amination]]s, wherein aldehydes or ketones are treated with an amine in the presence of this reagent:
It is especially favored for [[reductive amination]]s, wherein aldehydes or ketones are treated with an amine in the presence of this reagent:
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In conjunction with tosylhydrazine, sodium cyanoborohydride is used in the reductive deoxygenation of [[ketones]].<ref name=EROS/>
In conjunction with tosylhydrazine, sodium cyanoborohydride is used in the reductive deoxygenation of [[ketones]].<ref name=EROS/>


==Structure and preparation==
==Structure==
The {{chem2|[BH3(CN)]−}} ion is [[Tetrahedral molecular geometry|tetrahedral]] at the [[boron]] atom, and it comprises the anionic component of the salt.
Sodium cyanoborohydride is an ionic salt. The [[cationic]] sodium ion, {{chem2|[Na]+}}, interacts with the [[Ion|anionic]] cyanoborohydride ion, {{chem2|[BH3(CN)]−}}. The anionic component of the salt is [[Tetrahedral molecular geometry|tetrahedral]] at the [[boron]] atom.


== Preparation ==
The reagent is often purchased, although it can be prepared easily. One method involves combining [[sodium cyanide]] and [[borane]]. Another route is treating [[sodium borohydride]] with [[mercury(II) cyanide]]. The commercial samples can be purified, but the yields of the reductive aminations do not improve.<ref>{{Cite journal | author = Richard F. Borch and Mark D. Bernstein and H. Dupont Durst | title = Cyanohydridoborate Anion as a Selective Reducing Agent | journal = [[J. Am. Chem. Soc.]] | pages = 2897–2904 | volume = 93 | issue = 12 | year = 1971 | doi = 10.1021/ja00741a013}}</ref>
The reagent is often purchased, although it can be prepared easily. One method involves combining [[sodium cyanide]] and [[borane]]. Another route is treating [[sodium borohydride]] with [[mercury(II) cyanide]]. The commercial samples can be purified, but the yields of the reductive aminations do not improve.<ref>{{Cite journal | author = Richard F. Borch and Mark D. Bernstein and H. Dupont Durst | title = Cyanohydridoborate Anion as a Selective Reducing Agent | journal = [[J. Am. Chem. Soc.]] | pages = 2897–2904 | volume = 93 | issue = 12 | year = 1971 | doi = 10.1021/ja00741a013}}</ref>


Revision as of 03:58, 5 December 2023

Sodium cyanoborohydride
Wireframe model of sodium cyanoborohydride
3D molecular structure of sodium cyanoborohydride
Names
IUPAC name
Sodium cyanoboranuide
Other names
Sodium cyanotrihydridoborate
Identifiers
3D model (JSmol)
ECHA InfoCard 100.043.001 Edit this at Wikidata
EC Number
  • 247-317-2
UNII
  • InChI=1S/CH3BN.Na/c2-1-3;/h2H3;/q-1;+1
  • [BH3-]C#N.[Na+]
Properties
Na[BH3(CN)]
Molar mass 62.84 g·mol−1
Appearance white to off-white powder, hygroscopic
Density 1.20 g/cm3
Melting point 241 °C (466 °F; 514 K) decomposes
212 g/(100 mL) (29 °C)
Solubility soluble in diglyme, tetrahydrofuran, methanol
slightly soluble in methanol
insoluble in diethyl ether
Structure
4 at boron atom
Tetrahedral at boron atom
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Fatal if swallowed, in contact with skin or if inhaled
Contact with acids liberates very toxic gas
Contact with water liberates highly flammable gas
GHS labelling:
GHS02: FlammableGHS05: CorrosiveGHS06: Toxic
Danger
H228, H300, H310, H314, H330, H410
P210, P260, P264, P273, P280, P284
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
4
3
2
5 mg/m3 (TWA)
Safety data sheet (SDS) Sigma Aldrich[1]
Related compounds
Other anions
 Sodium borohydride
Related compounds
 Lithium aluminium hydride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Sodium cyanoborohydride is a chemical compound with the formula Na[BH3(CN)]. It is a colourless salt used in organic synthesis for chemical reduction; specifically, to reduce imines to amines.[2] The salt tolerates aqueous conditions.[3]

Use

Sodium cyanoborohydride is a mild reducing agent that is often used to convert imines to amines.[4] Its mild reducing qualities are owing to the presence of the electron-withdrawing cyanide substituent, [BH3(CN)]−. This structure causes it to be less reducing than is [BH4]−.[5]

It is especially favored for reductive aminations, wherein aldehydes or ketones are treated with an amine in the presence of this reagent:

R2CO + R'−NH2 + Na[BH3(CN)] + CH3OH → R2CH−NH−R' + "Na[BH2(CN)(OCH3)]" +H2O[clarification needed]

The reagent is typically used in excess. Selectivity is achieved at mildly basic solutions (pH 7–10).[citation needed] The reagent is ideal for reductive aminations ("Borch Reaction").[6]

In conjunction with tosylhydrazine, sodium cyanoborohydride is used in the reductive deoxygenation of ketones.[3]

Structure

Sodium cyanoborohydride is an ionic salt. The cationic sodium ion, [Na]+, interacts with the anionic cyanoborohydride ion, [BH3(CN)]−. The anionic component of the salt is tetrahedral at the boron atom.

Preparation

The reagent is often purchased, although it can be prepared easily. One method involves combining sodium cyanide and borane. Another route is treating sodium borohydride with mercury(II) cyanide. The commercial samples can be purified, but the yields of the reductive aminations do not improve.[7]

See also

References

  1. ^ Sigma-Aldrich Co., Sodium cyanoborohydride. Retrieved on 2014-11-09.
  2. ^ "Common Organic Chemistry - Home Page". www.commonorganicchemistry.com. Retrieved 2023-12-05.
  3. ^ a b Robert O. Hutchins; MaryGail K. Hutchins; Matthew L. Crawley (2007). "Sodium Cyanoborohydride". Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. pp. rs059.pub2. doi:10.1002/047084289X.rs059.pub2. ISBN 978-0-471-93623-7.
  4. ^ Christen, Hans; Meyer, Gerd (1997). Grundlagen der allgemeinen und anorganischen Chemie (1 ed.). Salle + Sauerländer. p. 824. ISBN 978-3-7935-5493-6.
  5. ^ Baxter, Ellen W.; Reitz, Allen B. (9 January 2002). "Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents". Organic Reactions: 1–714. doi:10.1002/0471264180.or059.01. ISBN 0-471-26418-0.
  6. ^ Richard F. Borch (1988). "Reductive Amination with Sodium Cyanoborohydride: N,N-Dimethylcyclohexylamine". Organic Syntheses; Collected Volumes, vol. 6, p. 499.
  7. ^ Richard F. Borch and Mark D. Bernstein and H. Dupont Durst (1971). "Cyanohydridoborate Anion as a Selective Reducing Agent". J. Am. Chem. Soc. 93 (12): 2897–2904. doi:10.1021/ja00741a013.
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