40949-94-8

Basic information

• Product Name: Potassium bis(trimethylsilyl)amide
• Synonyms: HexamethyldisilazanePotassiumSalt(15%inToluene);potassiumhexamethyldisilazane(solutioninthf);potassiumhexamethyldisilazane,khmds,in;potassiumhexamethyldisilazane,khmds,intetrahydrofuran;potassiumhexamethyldisilazane,khmds,intoluene;1,1,1,3,3,3-HEXAMETHYLDISILAZANE POTASSIUM SALT;KHMDS;HEXAMETHYLDISILAZANE POTASSIUM SALT
• CAS NO: 40949-94-8
• Molecular Formula: C₆H₁₈KNSi₂
• Molecular Weight: 199.48
• EINECS: 424-100-2
• Product Categories: Aliphatics;Analytical Chemistry;GC Derivatizing Reagents;Si (Classes of Silicon Compounds);Silazanes;Silylation (GC Derivatizing Reagents);Si-N Compounds;Trimethylsilylation (GC Derivatizing Reagents);Classes of Metal Compounds;K (Potassium) Compounds (excluding simple potassium salts);Silicon Compounds (for Synthesis);Synthetic Organic Chemistry;Typical Metal Compounds;25mL Sure/Seal Reagents;Chemical Synthesis;Organic Bases;Organometallic Reagents;Synthetic Reagents
• Mol File: 40949-94-8.mol
• Article Data: 8

Chemical Properties

• Melting Point: 194-195°C
• Boiling Point: 111 °C
• Flash Point: 45 °F
• Appearance: clear to slightly hazy yellow/Liquid
• Density: 0.877 g/mL at 25 °C
• Vapor Density: 3.2 (vs air)
• Vapor Pressure: 54 mm Hg ( 25 °C)
• Refractive Index: 1.4920
• Storage Temp.: Refrigerator
• Solubility: Miscible with terahydrofuran, ether, benzene and toluene.
• Water Solubility: Reacts with water.
• Sensitive: Moisture Sensitive
• BRN: 4006754
• CAS DataBase Reference: Potassium bis(trimethylsilyl)amide(CAS DataBase Reference)
• NIST Chemistry Reference: Potassium bis(trimethylsilyl)amide(40949-94-8)
• EPA Substance Registry System: Potassium bis(trimethylsilyl)amide(40949-94-8)

Safety Data

• Hazard Codes: C,F,Xn
• Statements: 14-34-67-65-63-48/20-11-40-36/37/38-19-37
• Safety Statements: 26-36/37/39-45-62-43-46-16-36/37
• RIDADR: UN 3263 8/PG 3
• WGK Germany: 3
• F: 1-3-10
• TSCA: No
• HazardClass: 3
• PackingGroup: II
• Hazardous Substances Data: 40949-94-8(Hazardous Substances Data)

Usage

Uses

Different sources of media describe the Uses of 40949-94-8 differently. You can refer to the following data:
1. Potassium bis(trimethylsilyl)amide is a strong base used in the alkylation carbonyl compounds.1
2. Potassium Hexamethyldisilazide is widely used as a Sterically Hindered Base for Enolate Generation in Selective Formation of Linear Conjugated Dienolates and Alkyl (Z)-3-Alkenoates.
3. Potassium Bis(trimethylsilyl)amide (1M in THF) is used in the preparation of 5-azacytidine, an antineoplastic drug. Also applied in the preparation of β3-AR agonists used in anti-stress formulations. It is also used as a reagent in the preparation of lanthanide complexes employed in selective cyclization reactions.

Preparation

Potassium Hexamethyldisilazide is prepared and isolated by the procedure of Wannagat and Niederpruem. A more convenient in situ generation from potassium hydride and hexamethyldisilane is described by Brown.

General Description

This product, 1.0 M in 2-methyltetrahydrofuran aligns with "Safer Solvents and Auxiliaries", "Use of Renewable Feedstocks" and "Inherently Safer Chemistry for Accident Prevention".

InChI:InChI=1/C6H18NSi2.K/c1-8(2,3)7-9(4,5)6;/h1-6H3;/q-1;+1

Synthetic route

lithium bis(trimethylsilyl)amide diethyl etherate

Conditions	Yield
With potassium tert-butylate In benzene at 20℃;	79%

tetrakis(trimethylsilyl)tetrazene → potassium hexamethylsilazane (40949-94-8)

Conditions	Yield
With potassium In diethyl ether at 25℃; for 1h;	100 % Spectr.

1,1,1,3,3,3-hexamethyl-disilazane (999-97-3) → potassium hexamethylsilazane (40949-94-8)

Conditions	Yield
With potassium hydride In tetrahydrofuran for 3.25h; Irradiation;
With n-Butyl chloride In tetrahydrofuran for 0.833333h; Yield given;
With potassium hydride In diethyl ether at 20℃; for 0.5h; Inert atmosphere;

hexamethyldisilazan (72525-60-1) → potassium hexamethylsilazane (40949-94-8)

Conditions	Yield
With potassium hydride In tetrahydrofuran; hexane at 20℃; Inert atmosphere;

CH3C9H6NCH(CH3)2(1+)*Cl(1-)=CH3C9H6NCH(CH3)2Cl + potassium hexamethylsilazane (40949-94-8) → C19H34N2Si2

Conditions	Yield
In toluene at -78 - 20℃;	100%

C14H25B9N2 + potassium hexamethylsilazane (40949-94-8) → C14H24B9N2(1-)*K(1+)

Conditions	Yield
In tetrahydrofuran for 0.25h;	100%

Upstream product

• 999-97-3 1,1,1,3,3,3-hexamethyl-disilazane 
• 18400-61-8 lithium bis(trimethylsilyl)amide diethyl etherate 
• 4039-32-1 lithium hexamethyldisilazane 
• 72525-60-1 hexamethyldisilazan 
• 52764-24-6 tetrakis(trimethylsilyl)tetrazene 

Downstream Products

• 144084-33-3 Potassium; 2,3,4-trimethyl-naphthalen-1-olate 
• 999-97-3 1,1,1,3,3,3-hexamethyl-disilazane 
• 144176-84-1 Potassium; (1aR,7R,7aR)-1a,7,7a-trimethyl-2-oxo-1a,2,7,7a-tetrahydro-1-oxa-cyclopropa[b]naphthalen-7-olate 
• 40203-74-5 methyl 2-cyclohexylideneacetate 
• 6651-36-1 1-(Trimethylsilyloxy)cyclohexene 
• 904894-75-3 2-[13C]-1-ethyl-3-isopropyl-3,4,5,6-tetrahydropyrimid-2-ylidene 
• 398125-21-8 4-{3-[[benzyl-methyl-amino]-methyl]-pyridin-2-yl}-1H-pyrrole-3-carboxylic acid ethyl ester 
• 139228-33-4 4-((2-cyano-2-phenyl)acetyl)-N-benzylpiperidine 
• 132392-25-7 O-[3,5-bis(1,1-dimethylethyl)phenyl]dimethylcarbamothioate 
• 769169-70-2 4,4,4-trifluoro-2-(triphenyl-λ⁵-phosphanylidene)butyric acid ethyl ester 

Relevant articles and documents

Convenient method for the preparation of a solution of potassium bis(trimethylsilyl)amide

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Formation of a hydride containing amido-zincate using pinacolborane

Amido-zincates containing hydrides are underexplored yet potentially useful complexes. Attempts to access this type of zincate through combining amido-organo zincates and pinacolborane (HBPin)viaZn-C/H-BPin exchange led instead to preferential formation of amide-BPin and/or [amide-BPin(Y)]?(Y = Ph, amide, H), when the amide is hexamethyldisilazide or 2,2,6,6-tetramethylpiperidide and the hydrocarbyl group was phenyl or ethyl. In contrast, the use of a dipyridylamide (dpa) based arylzinc complex led to Zn-C/H-BPin metathesis being the major outcome. Independent synthesis and full characterisation of two LnLi[(dpa)ZnPh2] (L = THF,n= 3; L = PMDETA,n= 1) complexes,1and3, respectively, enabled reactivity studies that demonstrated that these species display zincate type reactivity (by comparison to the lower reactivity of the neutral complex (Me-dpa)ZnPh2,4, Me-dpa = 2,2′-dipyridyl-N-methylamine). This included1performing the rapid deprotonation of 4-ethynyltoluene and also phenyl transfer to α,α,α-trifluoroacetophenone in contrast to neutral complex4. Complex1reacted with one equivalent of HBPin to give predominantly PhBPin (ca.90%) and a lithium amidophenylzincate containing a hydride unit, complex7-A, as the major zinc containing product. Complex7-Atransfers hydride to an electrophile preferentially over phenyl, indicating it reacts as a hydridozincate. Attempts to react1with >1 equivalent of HBPin or with catecholborane led to more complex outcomes, which included significant borane and dpaZn substituent scrambling, two examples of which were crystallographically characterised. While this work provides proof of principle for Zn-C/H-BPin exchange as a route to form an amido-zincate containing a hydride, amido-organozincates that undergo more selective Zn-C/H-BPin exchange still are required.

Preparation of α-Fluorobis(phenylsulfonyl)methane (FBSM)

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Crystalline 10,10-Bis((2-fluoro-4-pyridinyl)methyl)-9(10H)-Anthracenone and an improved process for preparing the same

The present invention relates to processes for the synthesis of a crystalline polymorph of 10,10-Bis((2-fluoro-4-pyridinyl)methyl)-9(10H)-Anthracenone in high purity. The product is useful in the synthesis of pharmaceutical compounds for the reduction of cholinergic system dysfunction.