Ammonium salts rearrangement

Mono-substituted and unsymmetrical di-substituted ureas may be prepared by a modification of Wohler s urea synthesis, salts of primary or secondary amines being used instead of the ammonium salt for interaction with potassium cyanate. Thus when an aqueous solution containing both aniline hydrochloride and potassium cyanate is heated, aniline cyanate is first formed, and then C,HjNH,HCl -h KCNO = C,H6NHj,HCNO -h KCl C,HsNH HCNO = C.H NHCONH, by the usual molecular rearrangement is converted into monophenyburea. 

Ammonium ion, JV-(2-thenyl)-N-benzyldimethyl-Stevens and Sommelet rearrangement, 4, 800 Ammonium salts, diallyldialkyl-polymerization, 1, 293 Ammonium salts, 2-pyrrolylmethyl-nucleophilic substitution abnormal, 4, 244 Sommelet rearrangement, 4, 244 Ammonium salts, trimethyl(l,3,5-triazinyl)-applications, 3, 525 Amobarbital, 3, 150 Amodiaquine, 1, 145 Amolanone applications, 4, 708... 

Hofmann rearrangement, 933 imide (-CONHCO—), 929 primary amine (RNH2), 916 quaternary ammonium salt, 917 reductive amination, 930 Sandmeyer reaction, 942 secondary amine (R2NH), 917 tertiary amine (R3N), 917... 

Benzylic quaternary ammonium salts, when treated with alkali metal amides, undergo a rearrangement called the Sommelet-Hauser rearrangementSince the product is a benzylic tertiary amine, it can be further alkylated and the product again subjected to the rearrangement. This process can be continued around the ring until an ortho position is blocked. ... 

Rearrangement of arylamines or aryl alkyl ammonium salts... 

Rearrangement of quaternary ammonium salts and tertiary benzylic... 

Starting materials other than sulphonyl azides have been used as possible sources of sulphonyl nitrenes. The decomposition of the triethyl-ammonium salt of iV- -nitrobenzenesulphonoxybenzenesulphonamide (26) in methanol, ethanol, and aniline gave products derived from a Lossen-type rearrangement 20> (Scheme 3). It was felt that the rearrangement did not involve a free sulphonyl nitrene since, when the decomposition was carried out in toluene-methylene chloride or in benzene, no products (benzenesulphonamides) of substitution of the aromatic solvent nucleus were found (as are usually found with sulphonyl nitrenes from the thermal decomposition of the corresponding azides). On the other... 

Partitioning of carbocations between addition of nucleophiles and deprotonation, 35, 67 Perchloro-organic chemistry structure, spectroscopy and reaction pathways, 25, 267 Permutational isomerization of pentavalent phosphorus compounds, 9, 25 Phase-transfer catalysis by quaternary ammonium salts, 15, 267 Phosphate esters, mechanism and catalysis of nucleophilic substitution in, 25, 99 Phosphorus compounds, pentavalent, turnstile rearrangement and pseudoration in permutational isomerization, 9, 25... 

Wittig rearrangement of benzylic quaternary ammonium salts upon treatment with alkali metal amides via the ammonium ylide intermediates. 

The behavior of tra s-[RuCl(=C=C=C=CH2)(dppm)2][PF6] towards the tertiary amine allyldimethylamine merits to be highlighted since the reaction led to the dimethylamino-allenylidene complex 32 through an Aza-Cope (or Claisen) rearrangement of the initially generated quaternary vinyl-allyl-ammonium salt [RuCl C=CC(NMe2CH2CH=CH2)=CH2 (dppm)2][PF6] (31) (Scheme 8) [47]. 

Miscellaneous PTC Reactions The field of PTC is constantly expanding toward the discovery of new enantioselective transformations. Indeed, more recent applications have demonstrated the capacity of chiral quaternary ammonium salts to catalyze a number of transformations, including the Neber rearrangement (Scheme 11.19a), ° the trifluoromethylation of carbonyl compounds (Scheme 11.19b), ° the Mannich reaction (Scheme 11.19c), and the nucleophilic aromatic substitution (SnAt)... 

Cleavage of a-aminoketones and their quaternary ammonium salts by sodium amalgam or zinc dust and acid has been used in synthetic procedures. This process was a key step in determining the stereochemistry of the Stevens rearrangement for... 

Quaternary ammonium N-F reagents, 69, 2 salts, rearrangements of, 18, 4 Quinolines, synthesis of,... 

There is extensive research ongoing for new synthesis processes which are economically favourable due to less expensive reactants or easier processes. One very important point is the avoidance of the production of a large amount of ammonium sulfate, which can be achieved by the prevention of the formation of any salt or by the replacement of ammonium sulfate by another ammonium salt with increased economical value. Recently, studies of Beckmann rearrangement of cyclohexanone oxime in friendly enviionment conditions have received special attention . ... 

The reactor systems were also improved, concerning the Beckmann rearrangement of cyclohexanone oxime and the production of the unwanted ammonium salts ", by-products and contaminants" ". 

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