Potassium amides

White or yellow-green hydroscopic crystals mp, 335°C sublimes at 400°C.  

Similar properties to the much more widely investigated sodium amide, but may be expected on general grounds to be more violently reactive. The frequent fires or explosions observed during work-up of reaction mixtures involving the amide were attributed to presence of unreacted (oxide-coated) particles of potassium in the amide solution in ammonia. A safe filtration technique is described.2 

More violently reactive than sodium amide.3 

Ammonia and Copper Nitrate. Explosive precipitate formed.4 

Potassium Nitrite. Explodes when heated with potassium nitrite under vacuum.5 

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The enyne system in the amines 828=88-8 8-882 can be reversed by potassium amide in liquid ammonia. Addition of the enyne amines to an equivalent amount of this reagent gives the potassium acetylides, K-8e8-88=88-8R2, from which the ynene" amines can be obtained in excellent yields by addition of solid ammonium chloride. 

Very strong bases such as sodium or potassium amide react readily with aryl halides even those without electron withdrawing substituents to give products corresponding to nucleophilic substitution of halide by the base... 

A solution to the question of the mechanism of these reactions was provided by John D Roberts m 1953 on the basis of an imaginative experiment Roberts prepared a sample of chlorobenzene m which one of the carbons the one bearing the chlorine was the radioactive mass 14 isotope of carbon Reaction with potassium amide m liquid... 

Nucleophilic aromatic substitution can also occur by an elimination-addition mechanism This pathway is followed when the nucleophile is an exceptionally strong base such as amide ion m the form of sodium amide (NaNH2) or potassium amide (KNH2) Benzyne and related arynes are intermediates m nucleophilic aromatic substitutions that pro ceed by the elimination-addition mechanism... 

Benzyne is formed as a reactive intermediate in the reaction of aryl halides with very strong bases such as potassium amide... 

Potassium Amides. The strong, extremely soluble, stable, and nonnucleophilic potassium amide base (42), potassium hexamethyldisilazane [40949-94-8] (KHMDS), KN [Si(CH2]2, pX = 28, has been developed and commercialized. KHMDS, ideal for regio/stereospecific deprotonation and enolization reactions for less acidic compounds, is available in both THF and toluene solutions. It has demonstrated benefits for reactions involving kinetic enolates (43), alkylation and acylation (44), Wittig reaction (45), epoxidation (46), Ireland-Claison rearrangement (47,48), isomerization (49,50), Darzen reaction (51), Dieckmann condensation (52), cyclization (53), chain and ring expansion (54,55), and elimination (56). 

Primary organic amines react with triethylsilane in the presence of the appropriate potassium amides to produce organoaminotriethylsilanes with yields of 82-92%. 

Cyanopyrazole is obtained from treatment of 4-amino-3-halopyridazines with potassium amide in liquid ammonia, while 4-amino-3,6-dihalopyridazines are rearranged under the same conditions to 3-cyanomethyl-l,2,4-triazole. 

In a series of reactions with potassium amide in liquid ammonia, 6-chloropyrido[2,3-f)]pyrazine gave reduction and ring contraction (Section 2.15.13.3), the 6-bromo analogue underwent only reduction, whilst the 6-fluoro derivative gave only the 6-amino substitution product (79JHC305). 

Reactions with strongly basic nucleophiles such as potassium amide in liquid ammonia may prove much more complex than direct substitution. 2-Chloro-4,6,7-triphenylpteridine reacts under these conditions via an S ANRORC mechanism to form 2-amino-4,6,7-triphenylpteridine and the dechlorinated analogue (78TL2021). The attack of the nucleophile exclusively at C-4 is thereby in good accord with the general observation that the presence of a chloro substituent on a carbon position adjacent to a ring nitrogen activates the position meta to the chlorine atom for amide attack. 

Pyridazine, 4-amino-5-formyl-3,6-dimorpholino-synthesis, 3, 346 Pyridazine, 4-amino-3-halo-reaction with potassium amide, 3, 29 Pyridazine, aryl-synthesis, 3, 28 Pyridazine, arylthio-synthesis, 3, 27 Pyridazine, 3-azido-... 

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