Semmler-Wolff reaction

Semmler-Wolff reaction. Rearrangement of ,(i-iinsaturatcd cyclohexenyl ketoximes into aromatic amines under acidic conditions. 

Semmler-Wolff Rearrangement, Semmler-Wolff Reaction)... 

This reaction was first reported by Semmler in 1892 and subsequently studied by Wolff in 1902 and Schroeter in 1911. It is the rearrangement of an oxime of an a,p unsaturated cyclohexenone (or known as the o, )0-unsaturated cyclohexenyl ketoxime) to an aromatic amine in a mixture of acetic anhydride and acetic acid saturated with HCl or HBr. Therefore, this reaction is generally known as the Semmler-Wolff aromatization," Semmler-Wolff rearrangement, or Semmler-Wolff reaction. Occasionally, it is also referred to as the Semmler-Wolff-Schroeter reaction. It should be pointed out that the Beckmann Rearrangement,and the fragmentation to nitriles often compete with the Semmler-Wolff aromatization. In addition, the Semmler-Wolff aromatization is obstructed by the substituents close to the reaction center. ... 

The aromatization of the oxime (115) of l-oxo-l,2,3,4-tetrahydroquinolizinium bromide (111) is carried out best by a modification of the Semmler-Wolff aromatization reaction... 

Quinolizinium bromide, 1-acetylamino-Semmler-Wolff aromatization, 2, 550 Quinolizinium bromide, 1-amino-2,3-dimethyl-reactions... 

The mechanism of the Semmler-Wolff aromatization of cyclohexenone oximes to anilines has been investigated further,and new reagents for the reaction have been reported/" ... 

Safety considerations were a driver to change the supply route in the synthesis of AZD1981 where the Makosza reaction was conducted above the flash point of acetone in the presence of air and the product nitro-indole (1, Scheme 8.2) was found to be thermally unstable. Furthermore, the yield in the first stage was low and variable (24 to 48%) impacting the overall cost and throughput. The AZ team developed a scalable, potential commercial route to AZD1981 by use of a Semmler-Wolff aromatisation of 2 to 3 to prepare the indole in 51% overall yield (Scheme 8.3). ... 

Acetyl chloride a,y -Ethyleneketones from oximes via a,y -ethylenimines Semmler-Wolff-type reaction... 

Several 1,4,5-benzotriazocines have been described in connection with medicinal chemical studies. The reaction of 2-chloromethylquinazoline oxide (313) with hydrazine gives the hydroxylaminotriazocine (314) and not a diazepine as originally assigned (73CPB2375). Vigorous acetylation of (314) causes a Wolff-Semmler type rearrangement to give the oxazolotriazocine (315). 

Wolff Rearrangement Wolff-Kishner Reduction Wolff-Semmler Aromatization Wolffenstein-Boters Reaction Woodward cis-Hydroxylation Wormall (see Dutt-Wormall Reaction)... 

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